The invention relates to the field of inspection of the containers, in particular glass, more precisely inspecting the finish surface of such containers in order to detect the presence of possible burrs at the location of an inner edge of the ring surface.
Illustrated in Figures 1A to 1C, in section through a radial plane, only the upper part of the neck of a container 14, which has a ring 12. Only one half of the section is illustrated. A container 14 is defined as a hollow container defining an interior volume which is closed over its entire volume periphery except at an upper ring 12 open at one end.

For convenience and only as arbitrary definition, it will be in fact considered that the container 14 has a notional central axis Al, defined as the theoretical center axis of the ring 12. It will also be arbitrarily considered that the ring is arranged at the upper end of the container. Thus, in the present text, the terms top, bottom, upper and lower have a relative value corresponding to the orientation of the device according to the invention and the container 14 as shown in FIGS. However, it is understood that the invention could be implemented with an indifferent absolute orientation in space, insofar as the individual components are arranged with the same relative arrangement.

The ring 12 of the container is cylindrical about the axis Al. The body of the container, not shown, could also be a volume of revolution or not. The ring 12 is connected by its lower end (not shown) to the neck of the container, while its other free end, said upper by arbitrary selection in the context of the present description, ends with a surface of ring 16.

The ring surface 16 is the top surface or upper edge of the ring 12 of the container, the ring being in the case of a bottle, the upper enlarged portion of the container neck. Shape of revolution about the theoretical center axis of the ring 12, in particular circular, annular or part-toroidal, the surface of ring 16 is more or less extended according to a direction radial to the central theoretical axis Al. In theory this surface is planar in a plane perpendicular to the theoretical central axis, in that it has at least one nip continues 360 ° around the axis in this plane and is perfectly circular. While being planar in the sense above, its radial profile, ie in cross section through a radial plane containing the theoretical central axis, can have different forms: the profile may be flat, rounded, inverted V, etc.

In the example shown in Fig. 1A, the ring surface 16 has a rounded radial profile, convex, between an inner edge 15 and an outer edge 17. The inner edge 15 will be considered as being at the intersection of the ring surface 16 and an inner surface 13 of the container finish, of which the general orientation is close to that of the axis Al of the container 14.

Among the defects that can be found on a ring surface, the invention aims to detect such defects "blunder" which, if present, are at the location of the inner edge 15 of the surface 16. These ring burr type defects are also called "ring lift" or "overpress". A burr is in the form of a defect of the radial profile of the ring surface section by a radial plane, this defect being situated at the location of the inner edge 15 of the ring surface 16. Generally, such a defect type burr is not punctual, thus not contained in a single radial plane, but extends over a circular arc around the theoretical axis Al of the surface of ring 16, usually at least 1 degree of angle around this axis.

A fault burr is characterized by an abnormal elevation in the direction of the theoretical axis of the ring surface. This height may be determined in relation to the height, in the direction of the theoretical axis of the ring surface, a circular line which is the intersection of the ring surface 16 with a reference plane perpendicular to the theoretical axis Al of the ring surface. Can be defined as such reference plane Pref the plane of Fig. 1A which is perpendicular to the theoretical axis Al and which contains a particular point Sref of the ring surface 16. This particular point may for example be the highest point of the collar surface 16 in the direction of the theoretical axis al. Alternatively, this particular point may be a point at which the ring surface has a normal having a predetermined angle relative to the direction of the theoretical central axis.

There is illustrated in FIGS. 1B and 1C two examples of ring 16 surface, which have, at the inner edge 15 of the collar surface, a type of defect burr. It is seen in both cases that this defect results in the formation at the location of the inner edge 15, a localized peak material which is surrounded radially outwards by a depression in the profile of the ring surface, and radially inwardly by the inner surface 13 of the ring 12. It is generally accepted that a type of defect burr extends in a circular arc around the theoretical axis Al. in the illustrated examples, the default can be characterized by an apex point or apex line S which represents the upper end of the barb in the direction of the theoretical axis Al. in a radial plane, we can thus define a height characteristic of a type of defect burr noting in this radial plane, the distance dZ between apex point S and a reference plane, e.g., plane Pref as defined above, which is equivalent to the difference in height in the direction of the theoretical axis al between the punch t Sref particular of the ring surface and the point summit S of the burr.

In the example of FIG. 1B, the point summit S of the burr is located below the reference plane Pref. In the example illustrated in FIG. 1C, the point summit S of the burr is located above the reference plane Pref.

Various methods and devices have been proposed for inspecting containers in order to determine the presence or absence of a fault-type burr as defined above.

US-4,811,251 and WO-2008/129650 disclose a burr detecting method. In these devices and methods, the ring surface is analyzed according to a radial plane, and it is necessary to rotate the container 360 to make a complete analysis of the surface. An illumination system comprises a central light source which allows locally illuminating the surface of ring in a direction which diverges from the axis at the incidence of the rays on the ring surface. The use of such a device requires a relatively large inspection time since it requires taking successive views As the container to be inspected is rotated about its axis, the axis of the remaining container stationary relative to the inspection device.

In addition, such a device which imposes a rotation of the container about its axis, is not really usable for in-line inspection of containers as they are scrolled, for example, in an inspection line, manufacturing , transport, processing or packaging. Indeed, this constraint imposes the introduction of the container into a checkpoint or inspection station, its rotated, the control for more than one lap, stopping the rotation, the extraction and delivery of mail online. In addition, handling machinery needed to introduce and extract the container checkpoint have high costs of acquisition and operation. US-0,878,705 describes another of those inspection devices requiring container rotation.

FR-2884611 proposes to use multiple cameras, each camera watching a particular angular sector of the ring. The lighting is produced by a light source of revolution centered on the axis. This solution has the disadvantage of using more expensive image sensors, and provides no instruction on the detection of burrs. In addition, different cameras each deliver only a partial image of the ring surface.

Therefore most systems preferably comprise a single camera optical axis centered on the theoretical center axis of the rings, realizing a direct two-dimensional image of the ring surface. All these systems allow translational inspection at high speed through the acquisition of a single image on articles by high speed translation, the displacement speeds of up to 1 m / s.

US-2001-048524 document presents a solution in which the lighting is dedicated to the detection of thread-like defects on ring by means of a tangential illumination. It is not suitable for viewing smudges. US-2004-150815 document provides a lighting solution in which a directional horizontal lighting is added to a diffuse lighting dome, and dedicated to the detection of burrs.

The document FR-2,846,422 proposes to combine multiple lights dedicated to the observation of different defects on the ring surface. The color camera is centered on the optical axis. A lighting, centripetal and shaving, illuminates the ring in order to reveal internal burrs.

Despite these efforts, these high speed inspection systems are not able to differentiate burrs according to their feature height, or to distinguish between an inner edge having a sharp edge but bright in the proposed lighting.

Moreover, there appears a need to distinguish between small burrs to ensure a higher quality, without making the mistake of confusing it with reflections from other elements of the container, for example by labeled edges of the ring or threads present on the ring. None of the above systems is not able to provide this discrimination.

In the broader field of machinery and container inspection methods, for the identification of other types of defects, including defects arranged on an outer cylindrical surface of the ring, it has already been proposed optical systems, including annular conical mirrors, which allow to observe the ring according to a peripheral field of view observing the ring according to the radial ray observations contained in radial planes containing the central theoretical axis Al, which are distributed through 360 ° around of the theoretical central axis, the observation field having a viewing elevation angle relative to a plane perpendicular to the axis of the ring. Such devices are for example described in EP-0047936 document, US-4758084, US-4959538, US-5661294, EP-0873510, EP-1606579, WO2016059343, US- 5,699,152, US 4,914,286 or US-2009/066944.

WO-2008/050 067 discloses a device for observing an area to be inspected of a container in several viewing angles in order to detect defects reflecting light in a preferred direction, which are therefore often observed in only one direction of observation.

The invention therefore aims to propose a device and a method of inspection that are compatible with in-line inspection of containers, so high speed, and which allows to determine reliably the presence or absence of a defect in Type burr at the location of the inner edge of the ring surface.

For this purpose, the invention provides a method for determining the presence of a glass burr at the location of an inner edge of a ring surface of a ring of a container, the ring surface having theoretical geometry as a surface of revolution about a notional central axis, of the type comprising:

* The lighting of the container collar surface from above, with an incident light beam comprising light rays incident radial contained in at least a radial plane containing the theoretical central axis,! Esdits radial spokes incidents away from the theoretical central axis at their incidence on the ring surface, and some of the radial spokes of the incident light beam being reflected by specular reflection on the ring surface, in the form of reflected rays;

* The formation, with the reflected rays, at least one image of the container finish surface, on a photoelectric sensor.

This method may be characterized in that:

* The incident light beam comprises light radial incident rays contained in radial planes distributed at 360 ° around the theoretical center axis;

The method comprises observing the ring surface, including the inner edge of the ring surface, from above, by an optical system according to a first peripheral field of view observing the ring surface according to first radial observation rays which are contained in radial planes containing the theoretical central axis, which are distributed at 360 ° around the theoretical central axis, the first peripheral field of view having a first elevation angle of observation with respect to a plane perpendicular to the theoretical central axis, so as to collect on a two-dimensional photoelectric sensor in a first annular zone of the sensor, to form a first two-dimensional digital image area:

o some of the incident light rays reflected by the first field of observation by the peripheral ring surface, forming in said first annular area image, a main circle;

o and possibly reflected rays according to the first peripheral field of view by the inner edge of the ring surface or a burr at the location of the inner edge, forming in said first image area, at least one arc secondary circle concentrically to said main ring and radially offset with respect thereto;

and in that the method comprises:

* Mark in said first image area, said main circle;

* Mark in said first image area, a possible secondary circle arc concentric to said main ring and radially offset with respect thereto.

According to other optional characteristics of the invention, taken alone or in combination:

- When appear, according to the first peripheral observation field having the first elevation angle of observation, parasites ray reflected by a portion of a wall of the separate ring surface ring and its inner edge which form in the first image area, residual images, one can modify the angle of elevation in a different value.

- The angle of elevation can be altered by replacing at least one component of the optical system.

- The method may include the observation of the ring surface and the inner edge of the ring surface, from above, by an optical system according to a second peripheral field of view observing the ring according to the second radial observation rays which are contained in radial planes containing the theoretical central axis, which are distributed at 360 ° around the theoretical central axis, the second peripheral field of view having a second angle of elevation relative to a plane perpendicular to the theoretical central axis, but different from the first elevation angle of observation, so as to collect on the same two-dimensional photoelectric sensor in a second annular zone of the sensor, to form a second zone two dimensional digital image:

o some of the incident light rays reflected along the second field of observation by the peripheral ring surface, forming, in said second image area, a main circle,

o and possibly reflected rays according to the second peripheral field of view by the inner edge of the ring surface or a burr at the location of the inner edge, forming in said second image area, at least one arc secondary circle, concentric with the main circle and radially offset with respect thereto;

and the method may include:

* Mark in said second image area, the main circle,

* Mark in said second image area, a possible secondary circle arc concentric to the main circle and radially offset with respect thereto.

- The method may comprise:

* Simultaneous observation by the optical system, the first peripheral observation field having the first viewing angle and the second peripheral observation field having the second viewing angle;

* The relative translation setting according to the theoretical center axis of a relative position of the optical system with respect to the container collar surface so as to allow the formation of a two-dimensional image of the container finish surface and its inner edge in either the first image area corresponding to the observation according to the first peripheral viewing field or the second image area corresponding to the observation according to the second peripheral field of view,

* And mark of a main circle and at least one arc of a secondary circle, or in the first area image or the second image area.

- The method may comprise:

* The simultaneous observation of the ring surface, including the inner edge of the ring surface by the optical system according to the first peripheral field of view and according to the second peripheral field of view;

* Simultaneously forming, from reflected rays collected in the first and second peripheral fields of view through the optical system, a two-dimensional image of the surface finish of the container and its inner edge simultaneously with the both the first image area corresponding to the observation viewing angle and the second image area corresponding to the observation viewing angle, on the same two-dimensional sensor, the first region image and the second image area being disjoint.

- The method may comprise:

* Selecting, for at least a series of similar containers, of a preferred image area of ​​the first and the second image area;

* Mark, for said series of containers, preferably in the image area, the DC main circle and arc corresponding secondary circle.

- The method may comprise searching for at least one container in the first image area, a first continuous main circle and a first secondary circle arc corresponding to said container and, in the second area image, a second DC main circle and a second circle arc corresponding secondary to said container.

- The method may comprise searching for each container of at least one series of containers of the same type in the first image area, a first main continuous circle and a first arc of a circle corresponding to a secondary said container and in the second image area, a second DC main circle and a second circle arc corresponding to said secondary container.

- The optical system may comprise a first primary reflection surface, the first primary reflection surface being a surface of revolution centered on the theoretical central axis and arranged to directly or indirectly reflect the light rays, from the ring surface by first field device observation, towards the sensor.

- The optical system may comprise a second primary reflection surface, the second primary reflecting surface being a surface of revolution centered on the theoretical central axis and arranged to directly or indirectly reflect the light rays, from the ring surface by second field device observation, towards the sensor.

- The formation of two-dimensional image area may include optical formation of a complete two-dimensional image and continues to 360 ° around the theoretical center axis of the ring surface on the same sensor.

- The method may comprise determining the presence of a burr when a radial gap distance between an arc of circle and the secondary nearest major circle, exceeds for at least one spoke, a threshold value.

- The method may comprise:

* Determining a radial gap distance between an arc of circle and the secondary nearest major circle; and

* Determining the presence of a burr when said radial gap distance exceeds, for at least one spoke, a threshold value.

- The method may comprise:

* Mark in the first image area, a first main circle and a first arc of a secondary circle and determining a radial spacing distance therebetween;

* Mark in the second image area, a second main ring and a second arc of a secondary circle, and determining a radial spacing distance therebetween;

* The mapping of the first and second arc of circle secondary found respectively in the first and the second image area as the two images according to the first and second observation field device of one burr;

* Determination by combining the radial distance measured distances to said first and second secondary arcs in the two image areas to determine a value dependent on a relative height of the burr relative to the collar surface;

* Determining the presence of a burr when the value exceeds, for at least an arc portion a threshold value.

The invention provides also an inspection device of the presence of a glass burr at the location of an inner edge of a ring surface of the container, the ring surface having a surface geometry as theoretical symmetrical about a notional central axis, of the type wherein the device has an installation area of ​​a ring surface of the container to be inspected, this installation area having an axis of installation, of the type comprising :

* An illumination system arranged above the installation area and capable of providing an incident light beam comprising radial spokes contained in at least a radial plane containing the axis of installation, said radial rays incident away axis installation at their incidence on the ring surface,

* An image sensor connected to an image analysis unit;

* An optical system arranged above the installation area interposed between the installation area and the sensor, and adapted to form an image on the sensor of the ring surface to be inspected placed in the installation area.

Such a device may be characterized in that:

* The sensor is a two-dimensional image sensor;

* The incident light beam is a beam comprising light radial incident rays contained in radial planes containing the installation axis and spaced at 360 ° around the axis installation;

* The optical system comprises at least a first primary reflection surface in an upstream field of vision of the sensor, the first primary reflection surface being a surface of revolution centered on the axis of installation, facing the installation axis , and arranged to reflect, directly or indirectly, in the direction of light rays of the sensor from the installation area along radial planes containing the axis of installation and device according to a first field of view having a first angle of elevation of observation with respect to a plane perpendicular to the central axis installation.

Furthermore, the device comprises at least one second primary reflection surface in the upstream field of vision of the sensor, the second primary reflecting surface being a surface of revolution centered on the axis of installation, facing the axis of installation and arranged to reflect directly or indirectly in the direction of light rays of the sensor, from the installation area along radial planes containing the axis of installation and device according to a second field of view having a second elevation angle observation with respect to a plane perpendicular to the central axis of installation, said second viewing angle being different from the first angle of elevation, the first primary surface and the second primary surface of reflection both being in disjoint portions of the upstream field of vision of the sensor.

In addition, the first primary reflecting surface and the second reflection surface for the sensor determine respectively a first portion downstream of field of view and a second field of view downstream portion overlapping in the inspection area.

According to other optional characteristics of the invention, taken alone or in combination:

- The first primary reflecting surface and the second primary reflection surface are frustoconical angles at different peak.

- The first primary reflecting surface and the second primary reflection surface are superimposed and have a common circular edge corresponding to a lower edge of the upper surface and an upper edge of the lower surface.

- The first primary reflecting surface and the second primary reflection surface are offset axially with respect to one another. - The first primary reflecting surface and the second primary reflection surface are offset axially by being axially separated to a non-zero axial distance between a lower edge of the upper surface and an upper edge of the lower surface.

- The first primary reflecting surface and the second primary surface reflection may be set for:

* Whereas a point on the collar surface;

* Whereas a first optical path followed between such point to the sensor by an incident ray reflected by the point under consideration of the collar surface according to the first viewing angle of elevation then reflected towards the sensor on the first primary surface reflection ; and

* Whereas a second optical path followed between such point to the sensor by a second incident ray reflected in the considered point of the ring surface according to the second elevation angle of observation and reflected towards the sensor on the second surface primary reflection;

the difference in length between the first optical path and second optical path is less than the depth of field value of the formed image when the optical system is developed on the ring surface.

- The first primary reflecting surface and the second primary reflection surface can be, according to a radial plane containing the central axis of installation, tangent to an ellipsoid of which a fireplace is the center of the entrance pupil of a lens system of a camera comprising the image sensor and whose second focal point is arranged on the central axis of installation, at the finish of the container to be inspected.

- The primary reflection surface is flared in the direction of the installation axis and has a large diameter and a small diameter both greater than the maximum diameter of the ring surface to be inspected.

- The primary reflecting surface may be a tapered surface facing the axis installation.

- The primary reflection surface can indirectly reflect light rays towards the sensor, and the device may then comprise, between the primary reflecting surface and the sensor, at least one reference reflection surface.

- The return reflection surface may comprise a surface of revolution facing away from the axis of installation to return towards the sensor rays.

- Between the sensor and the primary reflecting surface, the optical system may be telecentric.

- The incident beam device, may include, in the same radial plane, non-parallel radial spokes.

- The lighting system may include a central light source at least partly contained in a cylindrical envelope of revolution having as its axis the axis of installation and diameter the diameter of the inner edge of the ring surface to be inspected.

- The device may comprise an annular light source of revolution centered on the axis of installation, which generates light radial incident rays impacting the ring surface after installation intersected the axis between the source and the surface of Ring.

- The device may include a support supporting the sensor, the lens system, a primary reflection surface, a light source and optionally a deflection reflection surface.

The invention also relates to a container inspection line having a ring surface, of the type in which containers are moved on a conveyor line by a conveyor which conveys the containers in a direction of horizontal movement perpendicular to a notional central axis containers 14 which thus have their ring surface in a horizontal plane facing upward, characterized in that the installation comprises a device having at least one of the above characteristics, which is arranged on the installation with its axis installation in the vertical position, so that the observation field and the incident light beam are oriented downwardly towards the installation area which is located between the device and a conveying member of the conveyor.

In such an inspection line the conveyor can bring the containers so that their theoretical central axis coincides with the axis of installation, and when this coincidence, an image can be acquired by the device, contactless the device with the container.

Various other characteristics appear from the description given below with reference to the accompanying drawings which, as non-limiting examples, embodiments of the object of the invention.

Figures 1A, 1B and 1C illustrate in cross section through a radial plane, only the upper part of the neck of a container which has a ring. Only half of the section is illustrated,

Figure 2 is a diagrammatic axial sectional view of an inspection device according to the teachings of the invention, illustrating the optical path of two observation beam between the container and an observation camera.

Figure 3 is a diagrammatic axial sectional view of an inspection device according to the teachings of the invention, illustrating different portions of the sensor's field of view through an embodiment of a system. Figure 4 is an enlarged view of a portion of Fig. 3.

Figure 5 is a schematic axial section view of an inspection device according to the teachings of the invention, illustrating different portions of the sensor's field of view through another embodiment of a system. Figures 6 and 7 are enlarged views of a portion of Fig. 5, showing two relative positions of a container to be inspected relative to the inspection device, to obtain two different viewing angles of elevation.

Figure 8 is a view illustrating an image can be formed by the apparatus of FIG sensor. 3 in the presence of a container to be inspected in the installation area.

Figure 9 illustrates an alternative embodiment of the light source can be used with various embodiments discussed.

Figure 10 illustrates a container inspection line implementing an apparatus and / or method according to the invention.

Inspection of the ring surface by the method of the invention will therefore substantially consist in view, and can optionally at least to some embodiments, allow to quantify, a positional deviation, in the direction of the axis central theoretical Al and in the radial direction relative to this axis Al, between a main circle representative of the ring surface and a secondary circle arc representative of an apex line of a defect which would be present at the location of inner edge of the ring surface.

For a container 14 to be inspected properly, it should ensure that the container is presented properly before an inspection device 10, several embodiments are shown in Figs. 2-10.

For this, as shown for example in Figs. 2 and 10, a device 10 according to the invention determines a Z installation area in which the container is to be installed. This area of ​​installation can be defined by an axis of ΑΊ installation and an installation plan PI defined as a plane perpendicular to the axis of A'I facility located at the lowest point of the device. So, to be inspected properly, a vessel must be presented so that the theoretical central axis Al corresponds best to the axis of A'I installation, and that his ring be presented with its upper open end facing toward the device 10, but below the installation plan. In an ideal case, both Al and A'I axes coincide. It is understood that the entirety of the inspection device 10 according to the invention may be positioned above the installation plane while the container will be brought below the installation plan, without risk of contact with the device. The container 14 can therefore be brought by any translational movement along a

direction perpendicular to the axis of A'I installation without the risk of interfering with the device 10.

The device and method according to the invention involve a two-dimensional sensor 18 for acquiring a two dimensional image of the ring surface 16 of the container. This sensor, also called a matrix, may be incorporated into a camera 19 and it can be photoelectric, for example of the CCD or CMOS type. The sensor 18 is for example constituted by a two dimensional array of photoelectric elements. The sensor is typically associated with a signal processing electronic circuit provided by the photoelectric elements for providing a representative analog or digital signal of the image received by the sensor. This signal representative of the optical image received by the sensor is preferably a two-dimensional electronic image that may then be supplied to an image pickup unit including an image scanning device. With the development of digital cameras using image scanning function, preferably the signal representative of the optical image received by the sensor is a two-dimensional digital image which can then be issued to an image processing device and / or to an inspection device and / or an image storage device (not shown) forming an image analysis unit.

The sensor 18 is generally associated with an optical lens system 20, which may comprise one or more associated optical elements, including one or more lenses, and optionally a diaphragm, to allow the formation of an optical image on the sensor. The objective optical system 20 and the sensor 18 are typically part of the camera 19.

In some embodiments of the invention, the objective optical system 20 associated with the sensor 18 may be a telecentric lens system. A telecentric lens system is well known to those in the machine vision devices profession because it is used to form the sensor an image that has no or almost no parallax. In optics theory, a telecentric lens system is a

lens system including the entrance pupil is positioned at infinity. It follows that such an objective observes in his field of vision as the principal rays parallel observation or quasi-parallel, hence the lack of parallax. The main observation rays are those who pass through the center of the entrance pupil of the objective system 20. However, the lens system is not necessarily telecentric, as illustrated in FIGS.

The sensor 18 generally has a rectangular or square shape, so two-dimensional, so that it delivers a representative two-dimensional digital image of the two-dimensional optical image formed on the sensor by the optical system 20. overall image will be called Ig entire the digital image delivered by the sensor 18. It will be seen later that in this global digital image, only one or more image areas will help. Preferably, the overall image GI is acquired in a single acquisition time of the sensor.

The optical axis of lens system 20 is preferably coincident with the axis of ΑΊ installation. However, one might imagine that the optical axis is not straight but segmented eg by integration of a mirror in the lens system. This would provide a mirror at 45 ° with respect to the axis of installation, and with a first segment of the optical axis, the sensor side, to be arranged at 90 ° relative to the installation axis and a second segment, the other side of the reflecting mirror, which is arranged in line with the axis of A'1 installation.

In the illustrations of Figs 2-10, the optical system is arranged vertically along the ΑΊ axis, and is rotated downward to observe the installation area underneath the device, and to thereby observe a possible container 14 arranged in the installation area. The photoelectric sensor 18 is therefore at the top of the inspection device and is rotated downwardly in the direction of the installation area. With this arrangement, it is understood that the ring surface 16 of a container 14 placed in the installation area is therefore contained in a plane parallel to the plane of the sensor.

Also, according to the invention, an optical system 24 is interposed between the installation area Z of the container and the sensor 18 for forming on the sensor an image of the ring surface of such a container placed in the installation area . This optical system 24 includes, in addition to the objective optical system 20, at least one optical element vision device 22 which here is arranged between the objective system 20 and the installation area. The entire optical system 24 between the sensor 18 and the installation area Z and includes the objective system 20 and the optical element 22 of peripheral vision.

Conveniently, the axis of ΑΊ facility will be defined as the extension in the installation area of ​​the optical axis of the optical system 24.

In the example illustrated, the sensor 18, the objective system 20, the optical element of peripheral vision 22 and the installation area are aligned in this order along the same axis ΑΊ installation.

Through the optical system 24, at least one plane image was formed in the ring surface on the sensor through an optical geometric transformation that converts the ring surface in a ring surface image. Preferably, the geometrical optics transformation does not affect the relative angular positioning of two points on the ring surface around the axis, in the sense that two points of the actual ring surface, separated by an angular distance about the theoretical central axis, seen in the image obtained by the geometrical optics transformation, their respective separate images of the same angular spacing around the image of the theoretical central axis.

Advantageously, the optical system 24 allows the optical formation of a complete two-dimensional image and continues to 360 ° about the notional central axis Al of the ring surface 16 on the same sensor 18.

In the illustrated examples, the optical element of peripheral vision 22 which provides most of the optical processing comprises at least a first primary reflective surface 261 and, optionally, as in the particular embodiments which will be described below, a second primary reflection surface 262. the first primary reflective surface 261 and, optionally, the second primary reflective surface 262, are arranged in an upstream field of view of sensor 18, that is to say in the field of vision sensor that is between on one hand the sensor 18 and secondly the first primary reflective surface 261 and the second primary surface reflection 262. in the example shown, the upstream field of view of the sensor 18 is defined by the objective system 20.

The first primary reflective surface 261 is a surface of revolution centered on the axis of ΑΊ installation and arranged to reflect the light rays, from the collar surface in the direction of the sensor. The primary reflecting surface 261 thus has specular properties. It can be advantageously formed by a mirror, but it can also be in the form of a prism, ie an optical surface. The second primary reflective surface 262 advantageously has the same characteristics. The first primary reflecting surface and the second primary reflection surface are advantageously offset axially in the direction of the axis of A'I facility relative to another, that is to say, they are not arranged axially at the same level.

The axis of symmetry of revolution of the primary reflective surface 261 may be in this case considered as superimposed on the axis of A'I installation.

In the embodiments shown, the reflection of light rays from the surface to the sensor ring is a direct reflection, without further reflection surface.

In the examples shown, the first primary reflective surface 261 is a surface of revolution which is turned towards the axis of A'I installation. In the illustrated example, it widens toward the sensor. More specifically, the first primary reflection surface 261 has a concave frustoconical surface having a small diameter and a large diameter both greater than the diameter of the container ring surface to be inspected. Its large diameter is arranged on the sensor side depending on the installation axis while its smaller diameter is arranged on the side of the installation area. The second primary reflective surface 262 advantageously has the same characteristics. In this case, the first primary reflective surface 261 and the second primary reflective surface 262 are tapered at different angles summit.

In the examples having two primary reflection surfaces, the first primary reflective surface 261 and the second primary reflection surface 262 are preferably offset axially by being superimposed axially, that is to say directly joined to one another in the direction of the installation axis. Arbitrarily, we consider that the primary reflective surface which is located below the other in the direction of the axis of A'1 installation is the first primary reflection surface 261, the second primary reflection surface 262 being then arranged above the first. As in the examples illustrated having two primary reflection surfaces, the two primary reflection surfaces may then have a common circular edge corresponding to the lower edge of the upper surface, by the second primary reflection surface 262, and the upper edge of the surface below, by the first primary reflective surface 261. However, the first primary reflective surface 261 and the second primary reflective surface 262 may be offset axially by being axially separated to a non-zero axial distance between the lower edge of the upper surface and the upper edge of the lower surface.

In a device of the invention, the optical system 24 defines at least a first peripheral field of view which observes the collar surface from above, along radial observation beam contained in a radial plane containing the axis 'installation. Relative to the axis Al of the ring surface, this observation is made radially from the outside with respect to the ring surface. The radial observation beam are distributed at 360 ° around the axis of ΑΊ installation. The first peripheral field of view has, with respect to a pref plane perpendicular to the axis A'1 installation, a first angle of elevation γΐ observation, which is for example between 20 ° and 70 °. In the example illustrated, the first peripheral field of view includes the observation beam reflected from the first primary reflective surface 261 toward the sensor 18. In other words the first peripheral field of view is a first CAV1 downstream portion of the sensor field of view 18 through the optical system 24, as determined by the first primary reflective surface 261, between the first surface 261 and the installation area Z. in the portion of the observation beam which is between said first primary reflective surface 261 and the installation area Z, the observation beam are inward towards the axis Al when the path from the first surface 261 to the installation area Z.

In embodiments including the second primary reflection surface 262, the optical system 24 defines, via this second primary reflecting surface, a second peripheral field of view which observes the collar surface from above, along radial observation beam contained in a radial plane containing the installation axis. Relative to the axis Al of the ring surface, this observation is made radially from the outside to the ring surface. The radial observation beam are distributed at 360 ° around the axis of A'I installation. The second peripheral field of view has, with respect to a pref plane perpendicular to the axis of ΑΊ installation, a second angle of elevation Y2 observation, which is for example between 20 ° and 70 °, the second angle being different from the first angle of elevation γΐ observation. Preferably, the first and second observation elevation angle different by at least 5 degrees of angle. In the example shown the first peripheral field of view includes the observation beam which are reflected on the second primary surface 262. This second reflection peripheral field of view is a second portion downstream CAV2 the field of view of the sensor 18 through the optical system, as determined by the second primary reflective surface 262, between the second surface 262 and the installation area Z. in the portion of the observation beam which is between the second

primary reflective surface 262 and the installation area Z, observational rays are inward toward the axis Al when the path from the first surface 261 to the installation area Z. It is noted that the first primary surface 261 and the second primary reflection surface 262 are each in disjoint portions of the upstream sensor field of view in the sense that they can be simultaneously viewed by the sensor through the lens system 20, without masking to the other. Insofar to mask the other part, it is considered, to that which is partially obscured, the unmasked portion useful.

Preferably, the first and / or second peripheral field of view is without rupture azimuthally around the axis of A'1 installation. Notably, there is no azimuthal angular discontinuity between two radial spokes to infinitely close observation angularly about the axis installation. Thus, there is no breaking point seen in the image generated by the field considered, which could make the image difficult to interpret. For this the first and / or second reflecting surface 261, 262 is preferably without discontinuity of curvature about the axis of A'1 installation, the curvature being analyzed in a plane perpendicular to the axis installation ΑΊ to ensure a field without azimuthal break.

The first and / or second peripheral field of view is also preferably continuous in azimuth in the sense that no observation azimuth angle about the installation axis is hidden. However, in some cases, especially due to hardware installation constraints, the presence of a power cable, it is possible that one or more angular sectors around the axis of installation, are hidden. Preferably, such masked azimuthal angular sector will be low or very low extent, preferably less than 5 degrees about the installation axis. For this, the first and / or second reflection surface 26 is also preferably continuous in azimuth direction that is continually reflective about the axis of A'1 installation without hidden angular sector to ensure continuity azimuthal of the field.

The first and / or second peripheral field of view extends 360 ° around the axis of ΑΊ installation. The first and / or second peripheral field of view observed "from above" in the sense that the ring surface is observed from above Pref a theoretical plane perpendicular to the central axis Al of the ring surface and containing at least one point of the ring surface, for example the point Sref the highest in the direction of the central theoretical axis Al. in a peripheral field of view given observation rays are the rays from of the installation area and can be received, after reflection from the primary reflective surface 261, 262 corresponding, by the sensor through the optical system 24. of these rays, the main observation beam are those which, after reflection on the primary reflective surface 261, 262 corresponding, pass through the center of the objective of the CO entrance pupil observation system 20. the angle of elevation of a main observation radius corresponds to the angle to a plane perpendicular to the axis of A'I installation, an observation main beam in the installation area where it is likely to impact the container ring surface to be inspected.

As part of a device having a telecentric optical system, the main observation beam received by the sensor are all within the lens system parallel. If in addition, as in the illustrated systems, the primary reflective surface 261, 262 is a tapered surface generated by a straight line, the angle of observation γΐ elevation, γ2 of the corresponding peripheral field of view is then an angle unique for any observation principal ray belonging to the device field of view given, and it can be directly inferred from the inclination of the primary surface corresponding reflection 261, 262 with respect to the axis of ΑΊ installation.

However, in the case of a device not having a telecentric lens system, or in the case where the optical element 22 is not strictly a cone generated by a right observation beam received by the sensor, there including principal rays, may have different viewing elevation angles to each other within a peripheral field of view determined by a given primary reflection surface. In this case, we can take as a convention, as shown in Fig. 2 that the angle of elevation of a peripheral field of view is the angle, measured in the installation area where it is likely to impact the container ring surface to be inspected, relative to a plane perpendicular to the axis of A'I installation, a radial observation beam which, after reflection from the primary reflective surface 261, 262 corresponding, at mid-height thereof, is directed in towards the center of the entrance pupil of the objective system 20 CO.

The first and / or second primary reflection surface may be either tapered but a double-curved surface of revolution, widened, generated by revolution about the axis of A'I installation, a curved section non-straight, eg a parabolic section, hyperbola or ellipse. In a radial plane, this surface for example present a concave or convex profile, while retaining its concave profile in a plane perpendicular to the axis of A'I installation. Such a surface of double curvature may be used in particular to make the system 24, in its entirety, telecentric vis-à-vis the sensor, if the lens system 20 in itself is not, so that the peripheral field of view determined by the corresponding primary surface reflection comprises main observation beam, all having the same angle of elevation.

In a method according to the invention is formed here through the optical system 24, an optical two-dimensional image of the ring surface on the sensor through an optical geometric transformation that converts the collar surface in an image of ring surface. The same transformation converts a burr into an optical image of the burr on the sensor. These two two-dimensional optical images are converted into digital image respectively of the surface of the burr ring and, via the sensor, optionally with the aid of an electronic circuit more scanning if it is not not integrated with the sensor. If both primary reflection surfaces 261, 262 above are

present, forming two optical two-dimensional images of the ring surface on the sensor in two annular zones of the optical sensor and two-dimensional images of the burr on the sensor. These optical images are converted by two digital images of the ring surface CP1, CP2 and two digital images of the burr CS1, CS2 through the sensor. In practice, it may confuse the optical image formed on the sensor with the digital image supplied by the sensor, optionally with the aid of an electronic circuit more scanning if it is not integrated with the sensor .

Looking for example Fig. 1B, it is considered a point considered Sref of the ring surface and the corresponding point S of the burr which is the point of this burr which would have the same angular coordinate as the point Sref considered in a cylindrical coordinate system centered on the axis central theoretical. Looking, Fig. 8, it is considered that the point ISrefl ISref2 image or the image of the ring surface is the image of the point Sref collar surface through the optical system (possibly both ISrefl and ISref2 pictures in case of presence of two primary reflection surfaces as described above), because of the geometrical optics transformation. Point IS1 IS2 image or the image of the burr is the image of the point S corresponding to the burr through the optical system (possibly both IS1 and IS2 pictures in case of presence of the two primary surfaces of reflection as described above), because of the geometrical optics transformation.

Preferably, the optical geometric transformation performed by the optical system, converts a real difference in height dZ, in the direction of the theoretical central axis, between the Sref considered point of the ring surface and the corresponding point S of the burr, into a radial additional image shift, on the image, from the point ISrefl image Isref2 of the image of the container ring surface relative to the corresponding image point ISi, IS2 of the ring surface burr. this shift

radial additional picture is added to a radial offset resulting from the actual radial offset between the point and the point Sref corresponding S.

The optical geometric transformation performed by the optical system therefore generates, in the two-dimensional image collected by the sensor, an additional radial image shift resulting from an actual height difference between a Sref considered point of the ring surface and a corresponding point S of the burr.

In the examples of embodiment of the device according to the invention illustrated in Figs. 2 to 10, comprising at least one primary reflective surface 261, 262 frustoconical, concave in a plane perpendicular to the axis of installation, the half apex angle α1, a2 characteristic of the primary concave reflective surface 261, 262 determines a relative influence on the radial offset in the image between a height difference and a difference in radial position between a point on the surface of ring and a point of the burr located in the same half-plane delimited radial by the installation axis. In an exemplary embodiment, intended for containers the ring surface has an outer diameter smaller than 30 mm, the half apex angle a1 characteristic of the first primary concave reflective surface 261 is 20 degrees of angle, and creates a first peripheral field of view having a γΐ observation elevation angle of 40 °, while the half-apex angle a2 characteristic of the second primary concave reflective surface 262 is 13.15 degrees of angle, and creates a first peripheral viewing field having an angle of γ2 observation elevation 52 °.

According to another aspect of the invention, the method provides that the ring 16 of the container surface is illuminated with an incident light beam comprising light rays incident radial contained in at least a radial plane containing the central axis theoretical Al of the ring, said radial incident diverging rays of the theoretical central axis Al at their incidence on the ring surface, and some of the radial spokes of the incident light beam being reflected by specular reflection on the ring surface 16, in the form of reflected rays. The incident light beam comprises light radial incident rays contained in radial planes distributed at 360 ° around the theoretical center axis Al.

The ring surface is illuminated from above, in the sense that incident light rays reach the ring surface 16 from points located above the plane Pref perpendicular to the theoretical central axis Al and containing a point of the ring surface, e.g., the highest point in the direction of the central theoretical axis Al.

The radial rays incident may be parallel rays, but this is not mandatory and, in the process illustrated in Figs.4 and 5, the light beam incident device comprises, in a given radial half-plane containing the axis central theoretical Al and delimited by the theoretical central axis a, non-parallel radial spokes.

In a device according to the invention, the device thus comprises a lighting system capable of providing such an incident light beam.

Preferably, this lighting system includes a light source 28 centered on the axis of A'I installation and arranged above the installation area, so above the ring surface.

In a first embodiment, shown in Figs. 4 and 5 in particular, the illumination system comprises a light source 28 Central at least partially contained in a cylindrical envelope of revolution having as its axis the axis of ΑΊ installation and diameter the diameter of the inner edge 15 of the surface ring to be inspected. Such a light source may be a point source centered on the axis of installation, or the contrary, as shown in Figs. 4 and 5 in particular, a source covering a certain extent radially with respect to the installation axis. In some embodiments, the light source 28 covers a range of less than or equal diameter to the diameter of the container finish. The light source 28 may be a diffuse source, diffusing the incident rays in multiple directions. For example, the light source 28 may comprise a diffuser which, for example, covers an area whose diameter may be less than or equal to the diameter of the container finish. If it is provided with a diffuser, each point of the diffuser, the light source 28 diffuses the incident rays in multiple directions. Preferably, the radial extent of the central light source 28 and orientation of the incident rays it emits are chosen so that the incident rays can not directly impact an outer cylindrical surface of the ring 12, located below the outer edge 17, or the threads worn by such an external cylindrical surface of the ring 12.

Alternatively, as illustrated in Fig. 9, the device could include a light source 28 'is circularly annular, centered on the axis of A'I installation, which generates light radial incident rays impacting the installation area after installation intersected the axis ΑΊ. In this case, the annular light source may have an inner diameter greater than the diameter of the ring surface of the containers it is desired to control by means of the device. In a radial half-plane containing the axis of ΑΊ installation and delimited by the axis of installation, such an annular light source corresponds to a source which may be a point, or on the contrary can have a radial extent in this half -plan as illustrated in FIGS. This light source illuminates in the direction of the installation area, thus in the direction of the axis of installation, but forming therewith an angle so as to illuminate down. If this source is a source emitting parallel rays, it emits Preferably, in this radial half-plane, a light cone containing radial spokes in a continuous or substantially continuous range. This range may for example form an angular sector ranging between 0 and 40 degrees relative to a theoretical plane perpendicular to the central axis. The angular range is preferably limited extent by one or more caches, which may for example comprise a diaphragm, so that the incident rays can not directly impact an outer cylindrical surface of the ring 12, located below the outer edge 17, or the threads worn by such an external cylindrical surface.

In the example of FIG. 9, the light source 28 'is annular and arranged just below the optical element vision device 22, here below the first primary reflection surface. It could also be arranged around the peripheral vision optical element 22.

Insofar as the light source 28 'is annular, it can be considered a variety of sources, optionally point or quasi-point, arranged around the axis A'1 installation and each emitting array of such light that defined above. Preferably, the light source is continuous over the entire periphery 360 ° about the axis of installation, in the sense that in each radial half-plane, it emits the same light spectrum. However, in reality, the light source is generally not perfectly still. It is also it is interrupted over an angular sector, preferably limited, around the axis ΑΊ. It may be also that the light source is not continuous, in the sense that it would be formed by a series of individual sources juxtaposed discrete, for example formed by a series of light emitting diodes.

In general, the light source 28, 28 'comprises a series of individual sources juxtaposed discrete, for example formed by a series of light emitting diodes, these juxtaposed individual sources being associated with a diffuser so that the light source then supplies a lighting which can be considered as continuous and diffuse.

The light spectrum delivered by the light source 28 may be monochromatic or polychromatic, for example extending over a range of wavelengths. The light spectrum delivered by the light source 28 preferably includes wavelengths in the visible range.

In a preferred variant, the light source 28 includes white LEDs, whose emission spectrum spans the visible range.

In the invention is formed with the reflected rays, at least one image of the container finish surface, on the sensor 18, as illustrated in Fig. 8.

Through observation of the surface of ring 16, including the inner edge of the ring surface by the optical system according to the first peripheral field of view is collected on the two-dimensional photoelectric sensor in a first annular zone of the sensor to form a first image area, in the numerical example, two-dimensional ZI1:

- some of the incident light rays reflected, according to the first peripheral field of view with the viewing angle of elevation γΐ by the ring surface to form in said first area ZI1, a first main circle IPA;

- and, optionally, if a burr is present at the inner edge, the reflected rays, as the first peripheral observation field having the first angle of elevation γΐ observation, by the inner edge of the ring surface or by a burr at the location of the inner edge, forming in said first image area, at least one first secondary circle arc concentric with the first CSl main circle IPA and radially offset with respect thereto.

The first ZI1 image area in which we can expect to find the first main circle CPI and a possible first arc of secondary circle CSl is here an annular zone. Next optical transformation performed by the optical system 24, the secondary circle CSl can be found radially outside the first main circle IPA, as in the example of FIG. 8, or on the contrary to the interior thereof.

The first main IPA circle corresponds to a portion of the ring surface formed of points that have such normal that there exists at least one incident ray by specular reflection at that point, is reflected, after reflection on the first primary surface Brain 261, according to an observation range of the first peripheral field of view. Depending on the configuration of the incident light beam, in particular according to

the extent of the light source 28, the diffuse or not the light source, and profile of the surface of ring in sectional view in a radial half-plane, the thickness of the first circle CP1 will be more or less important. Indeed, according to these parameters, there will be in a given radial half-plane, one or more points of the ring surface to enable the reflection of an incident beam towards the sensor through the optical system 24. however, particularly if the ring surface has a curved profile, portions of the ring surface are not visible in the image of the ring surface, failing to return beams reflected according to the first peripheral viewing field having .

With a device as described above, the first main circle CP1 is generally continuous 360 ° ring if the surface does not exhibit other defects that any burr at the location of its inner edge.

the convention that the center of the first main circle ICC can take determines a central axis A "the image, this axis being the image of the theoretical central axis Al of the ring surface.

To determine the presence of a burr at the location of the inner edge of the ring surface, the method comprises, for example:

- searching, in said first image area ZI1, the first main circle ICC;

- searching, in said first area of ​​Zil image of a possible secondary arc of circle concentric to the first main CS1 circle ICC and radially offset thereto.

However, in the example shown in Fig. 8, we see that the first ZLL image area comprises two complete concentric circles 360 °, so that the observed container has a burr which extends only over approximately half a circle. The explanation for this is as follows.

Figure 2 illustrates an incident ray RI emitted by the light source, which is reflected by an apex point S to a burr located at the location of the inner edge of the ring surface at a reflected ray which is RRl

intercepted by the first primary reflection surface 261, in a RS1 point and so reflected towards the sensor by the optical system. As discussed above, it is considered that the S point is the point locally highest of the barb profile into the corresponding radial half-plane. In practice a burr almost always has a sharp edge so that there is a point very close to the highest point, so that one can consider the confused, able to return an incident beam according to the angle of elevation observation.

The points S of the burr and the first reflection surface 261, the radius RR1 is propagated along an observation range of the first peripheral field of view. However, if one extends the direction of the radius RR1 in its portion lying between its point of RS1 reflection on the first reflecting surface 261 and the ring beyond the point summit S of the burr, it is seen that this direction which corresponds to an observation beam has an impact point S 'of the ring of the bottle which is capable of reflecting an incident light ray according to the same observation beam. In other words, the point S 'of the ring, here for example a point of the lower outer peripheral edge of the ring, sometimes called the "against-ring surface" or "bottom ring" is likely to reflect on the same point RS1 reflection on the first reflecting surface 261, so that the point S and the point S 'will be combined in the image formed on the sensor and therefore in the digital image. Typically, this reasoning applies to 360 ° about the installation axis. In this case, the point S 'is part of a circular peripheral edge which extends 360 ° around the axis A so that it appears on the image a parasitic reflection RP, here in the form of a circle which is partially coincident with the first arc of circle secondary CS1. It is therefore understood that for this particular case of vessel 14, due to the particular geometry of the ring, and because of particular observation elevation angle determined by the first reflection surface 261, the image obtained the device may not be satisfactory to effectively determine the presence or absence of a burr.

At this point, we note that this particular case in which a parasitic reflection prevents proper determination of the presence of a burr is a special case. In many cases, a device having a single primary reflection surface as described above allow for many containers, to a quite efficient detection of the presence of a burr at the location of an edge internal of the ring surface. Indeed, in the absence of parasitic reflections, this determination will be through comparative analysis of the first main circle and the first arc of secondary circle the same manner as described below in connection with a second main circle and a second secondary circle arc formed in a second image area.

However, when displayed, according to the first peripheral observation field having the first angle of elevation γΐ observation, parasitic rays reflected by a portion of a wall of the ring, separate from the ring surface 16 and distinct from its inner edge, which form ghost images in the first area of ​​ZI1 picture, including arcs of circles similar to those produced by the inner edge or burr, it is advantageous to modify the viewing angle of elevation γΐ in a value Y2 of different observation elevation angle.

The angle of elevation can be altered by replacing at least one component of the optical system 24, in particular by replacing the first surface of primary reflection. One could thus provide a device wherein the optical element vision device 22 including the first surface of primary beam 261, is interchangeable with other optical elements of peripheral vision which present a primary reflection surface defining another angle different observation elevation. However, the replacement of an optical element with another is a procedure which can be complex and may require alignment settings.

Therefore, in an improved embodiment, the invention provides for the observation of the surface of ring 16 and the inner edge of the

ring surface, from above, by the optical system 24, according to a second peripheral field of view determined by the second surface 262 of primary reflection.

With this second surface primary beam 262 is collected on the same two-dimensional photoelectric sensor 18, a second annular zone of the sensor to form a second region of two-dimensional digital image ZI2:

- some of the incident light reflected rays, according to the second observation device having the second Y2 observation elevation angle by the collar surface, forming, in said second zone ZI2 image, a second main circle CP2;

- and, optionally, of rays reflected by second peripheral observation field having the second observation elevation angle Y2 by the inner edge 15 of the collar surface 16, or a burr at the location of the inner edge, forming in said second image area, at least one second secondary arc CS2 circle concentric with the second main circle CP2, and radially offset relative thereto.

Fig. 2, it is seen that the RI incident beam is reflected by the point summit S of a second reflected ray RR2 which is intercepted by the second primary reflection surface 262, in a RS2 point and so reflected towards the sensor 18 by the optical system 24 . in this example, if one extends the direction of the second reflected ray RR2, beyond the point summit S of the burr, it is seen that this direction, which corresponds to a radius of observation, has impact on the ring of the bottle at points which are not likely to reflect an incident light ray according to the same observation beam. Thus, this observation radius is not affected by a parasitic image. Advantageously, this is true at 360 ° around the axis of the installation.

Therefore, as shown in Fig. 8, with this modification of the angle of elevation can be clearly distinguished in the second zone of ZI2 image, the second main primary circle CP2 and the second arc of a circle secondary CS2. The "second" qualifier which is used here for the second main circle and the second circle arc secondary derives from what they are in the second image area, corresponding to the second angle of elevation.

The second ZI2 image area in which we can expect to find the second main circle CP2 and a possible second arc of a circle CS2 is secondary here an annular zone. Next optical transformation performed by the optical system 24, the second arc of a circle secondary CS2 may be radially outside the second main circle CP2, as in the example of FIG. 8, or on the contrary to the interior thereof.

The second main circle CP2 corresponds to a second image of a portion of the formed ring surface points which are normal such that there is at least one incident ray by specular reflection at that point, is reflected, after reflection on the second primary reflective surface 262, according to an observation range of the second peripheral field of view. As with the first main circle CP1, the thickness of the second circle CP2 will be more or less important, and it is generally continuous 360 ° ring if the surface does not exhibit other defects that any burr at the location its inner edge.

To determine the presence of a burr at the location of the inner edge of the ring surface, the method comprises, for example:

- searching, in said second zone ZI2 image of the second main circle CP2;

- searching, in said second image zone Z 2, a possible second arc secondary CS2 circle concentric to the second main circle CP2 and radially offset with respect thereto.

In the overall digital image, the first and second main circle and the first and second arc of a secondary circle can be identified by a brightness value greater than a background brightness value of the image.

Whether for the first area image or the second image area, it is considered that, in the absence of burr at the location of the inner edge, the inner edge then has its nominal geometry. In this case, it will be found or not, a secondary circle arc optionally corresponding to this inner edge. This will depend in particular from the nominal geometry of the inner edge, depending on which of the incident rays will be reflected or not, in the direction of the primary reflection surface. If the inner edge of nominal geometry reflects the incident rays toward the sensor with consideration of the corresponding primary surface, then it is possible that the secondary arc of circle corresponding to the inner edge extends over 360 °. If the opposite inner edge of nominal geometry does not reflect the incident rays towards the sensor, then there will be no visible bow secondary circle in the corresponding image area.

It is thus clear that there is an interest to limit the cases in which parasitic reflections could affect the accuracy of determining the presence of a defect type burr to provide observation of the ring surface and its inner edge in two different viewing angles of elevation.

Preferably, these two viewing angles of elevation is achieved through two primary surfaces of discrete reflection arranged on both the device and generating these two angles.

Alternatively, it is expected that these two primary reflection surfaces are arranged on both the device and that a drag operation on between the container and the optical system, one can form an image of the ring surface and the burr possible either via the first primary reflective surface 261, either through the second surface of primary reflection 262, but not both simultaneously. This variant is illustrated in particular in Figs 5, 6 and 7.

Fig. 5, there is illustrated in effect the sensor 18, the lens 20, here shown schematically as a lens, the optical element 22 having the first primary reflective surface 261 and the second primary reflection surface 262, the source bright central 28 and the container 14, which have the characteristics described above.

The first primary reflective surface 261 and the second primary surface reflection to determine the sensor respectively a first portion of CAV1 downstream field of vision and a second portion downstream of CAV2 field of view. The first and second field of view downstream portion includes all points in space of the installation area for which an image is formed on the sensor 18 by the optical system, respectively after reflection on the first or second primary reflection surface. In section through a plane perpendicular to the axis of installation, these field portions downstream vision CAV1, CAV2 are annular. Since the primary surface of corresponding reflection, these downstream fields of view portions are directed downward, inward towards the installation axis so as to form an annular truncated cone having a half angle at the top of complementary 'viewing angle of elevation.

It is understood that for an image is formed of the ring surface 16 by reflection off one or other of the two primary surfaces of reflection, it is necessary that the ring surface is installed in the downstream portion of field of view CAV1 correspondent CAV2.

As illustrated in Figs. 6 and 7, this embodiment is such that there is no common inspection zone in which the two field portions downstream vision CAV1, CAV2 would overlap is and wherein the ring surface may be received.

On the contrary, we see in Fig. 6 that the container 14 must be placed in a first axial position relative to the device 10 so that the ring 16 surface is comprised in the first field portion downstream vision CAV1 which is determined by the first surface 261. In primary beam this position, only the first main circle and an optional first secondary circle are formed in the overall image. In the illustrated example, we see that at least one observation beam of the first peripheral field of view is likely to intercept an incident ray reflected by an outer surface S 'of the ring which is not that it is desired to detect. It is therefore a parasite reflection and that will generate a spurious image in the image produced after reflection on the first primary reflective surface 261.

In Fig. 7, it is seen that the container 14 occupies relative to the device 10, a second axial position, offset in the direction of the axis of installation in relation to the first, so that the surface of ring 16 is comprised in the second downstream portion of field of vision CAV2, which is determined by the second surface of the primary reflection 262. in this second position, the same container does not generate parasitic reflection that would be visible according to the second peripheral field of view, which would be likely to create a parasitic image. In this position, only the second main circle and a possible second secondary circle are formed in the overall image.

The relative movement of the container relative to the device can be created for example by providing that the device, or part thereof, is mounted via a support 230 which may be movable, for example by means of a slider 21 on a frame 11 occupying a fixed position relative to a container conveying device. By moving the inspection device 10, or part thereof, along the slide can be adjusted by translating the relative position of the device, and therefore the optical system, with respect to the ring surface of a container in the installation area. It is also possible that the containers are conveyed by a conveying device adjustable in height at an inspection station comprising the inspection device.

With such a device, it provides simultaneous observation of the ring surface by the optical system 24, as the first peripheral observation field having the first γΐ observation angle and according to the second peripheral observation field having the second angle γ2 observation because the two reflective surfaces are contained in disjointed portions of the upstream field of view of the sensor. However, with

such a device, one must carry out the adjustment, by relative translation according to the theoretical central axis, the relative position of the optical system with respect to the container collar surface so as to allow the formation of a two-dimensional image of the surface finish of the container and its internal edge is in the first zone of ZI1 image corresponding to the observation according to the first the second peripheral observation field having the first γΐ viewing angle, or the second zone ZI2 image corresponding to the observation according to the second peripheral observation field having the second Y2 viewing angle.

In this case, an overall digital image data GI, issued by the sensor 18, there is a single image of the ring surface and a single image of the possible burr, in one or the other of the two zones 'picture.

It will be noted that the relative movement between the optical system and the ring surface is preferably accomplished by maintaining the relative positions of the optical system and its components relative to the objective system 20, the sensor 18 and the light source 28 . in this case, moving the container 14 relative to the device 10 in the direction of the axis of A'I installation. However, alternatively, it is possible, at least in some embodiments, that the relative movement between the camera 19 and the optical system and the ring surface also involves a relative movement between the camera 19 and the optical viewing element 22 device that bears the primary reflection surfaces.

In all cases, on the basis of an overall image acquired by such a device, one can then determine the presence or absence of a burr by searching in an overall image acquired by the sensor 18, a main circle and least an arc of a secondary circle, in either the first ZI1 image area or the second ZI2 image area.

In such a system, it could certainly provide that, for each container, acquire two global images each corresponding to one of the relative positions of the container 14 of device 10. However it is understood that this would not be optimal. In fact, we understand that the reflection problems

parasites that may be encountered with either peripheral fields of observation are intrinsically linked to the geometry of the container. On an inspection line, manufacturing, conveyor or container packaging, the containers are generally all of the same type having the same geometry, at least for a significant period of time. Also, with such a device does not allow the simultaneous formation, in the same global image, an image of the ring surface and possible flash device according to the first field of view, and an image of the ring surface and possible flash device according to the second field of view, the procedure preferably at the beginning of inspecting a series of container, at a preset stage of the angle of observation elevation to use for a given type of container. This predetermination step can be performed manually by an operator who will appreciate the presence of stray light may interfere with the inspection. For example, comparing an image taken by the first peripheral field of view and an image taken by the second peripheral field of view, we can determine which of the two images will give the most reliable inspection results. This comparison can also be made automatically by computer analysis of these two images. Based on this analysis, we can then choose either observation elevation angles and adjust the relative position of the device relative to the container early inspection to keep throughout the inspection series of identical geometries containers.

However, in a preferred embodiment of the invention, as illustrated in FIG. 2, in FIG. 3 and Fig. 4, the two primary reflection surfaces are chosen and arranged relative to the device such that the optical system forms simultaneously on the sensor 18, two separate images in two separate areas of the sensor, so that the latter delivers an image overall comprising two distinct image areas, each separate image area having an image of the ring surface and an image of a possible burr formed from the collected rays depending on the device observation field having the angle of observation elevation determined by the corresponding primary surface reflection.

Such a global image is in particular that shown in Fig. 8.

Thus, the device of FIGS. 2, 3 and 4 permits the simultaneous observation of the surface of ring 16, including the inner edge of the ring surface by the optical system 24, 124, according to the first peripheral field of view and the second field of device observation. Thus, this allows the simultaneous formation, from the reflected rays collected in the first and second peripheral fields of observation through the optic 24 of a two-dimensional image system CP1, CP2 of the container collar surface and CS1 , CS2 its internal edge simultaneously in both the first area of ​​ZI1 image corresponding to the observation according to the first peripheral observation field having the first angle of γΐ observation and in the second image area corresponding to Z2 the observation that the second peripheral observation field having the second Y2 viewing angle, on the same two-dimensional sensor 18, the first image area and the second image area being disjoint.

In this case, therefore have, for each container, an overall image comprising two image areas each including an image of the ring surface and a possible burr, in two different viewing angles of elevation. This overall picture IG is preferably acquired in a single acquisition time of the image sensor 18.

For this, the optical element of peripheral vision 22 which comprises the first primary reflecting surface and the second reflection surface is designed so that these two surfaces define, for the sensor, respectively a first portion of annular CAV1 downstream field of view and a second field portion of vision annular downstream CAV2 overlapping in a common inspection area in the installation area. This common inspection area is an area of ​​the space comprising the set of points that can be received by the sensor 18 through the optical system 24 at a time after reflection on the first primary reflective surface 261 and after reflection on the second primary reflection surface 262. the geometry of the joint inspection area must be adapted to be able to receive a container ring surface to be inspected.

Preferably, optimize the first primary reflecting surface and the second primary reflective surface such that the two images of the ring surface and possible burrs obtained on the one hand by reflection on the first primary reflection surface 261 and also by reflection from the second primary reflective surface 262, or net for a same setting of focus of the device.

In particular, we provide that the first primary reflecting surface and the second primary reflection surface are positioned:

- considering a point S of the ring 16 arranged surface in the common inspection zone;

- whereas a first optical path RR1 followed, the points considered S and the sensor 18, by an RI incident ray reflected in the considered point S of the ring surface according to the first peripheral observation field having the first elevation angle observation then reflected towards the sensor on the first primary reflective surface 261; and

- whereas a second optical path followed RR2 between the S such point to the sensor 18 by an incident ray reflected by the point considered S of the ring surface as the second peripheral observation field having the second angle of elevation of observation and reflected towards the sensor on the second primary reflective surface 262.

In this case, the difference in length between the first optical path and second optical path is less than the camera's depth of field value 19 when the optical system is developed on the ring surface.

In known manner, the depth of field is represented by the set of points contained between two planes perpendicular to the optical axis of the optical system for which points are seen net for a given focus the optical system. The depth of field value corresponds to the distance between these two planes.

This property provides maximum sharpness in both image areas ZI1, ZI2 with the same setting of focus of the optical system 24.

One way to get this property is to provide that the first primary reflecting surface and the second primary reflection surface are, according to a radial plane containing the central axis of installation, tangent to an ellipsoid whose foci are arranged on the axis of A'I installation. A first focus of the ellipsoid is arranged CO center level of the entrance pupil of the objective system 20. The second focus of the ellipsoid is arranged on the central axis of ΑΊ installation, at the level of the ring 12 the container to be inspected. Given the depth of field value for the optical systems used in the field of the invention, there is a tolerance for the exact position of households, particularly in the direction of the axis of installation.

In the event that the inspecting a series of identical geometries vessel may be provided using only one of the two images, after a step of predetermining comprising eg selecting for at least a series of containers of the same type , of a preferred image area of ​​the first and the second image area, in the same manner as was discussed above in relation to the previous embodiment. In this case, analysis of an image, for determining the presence of a burr at the location of the inner edge of the corresponding container, may comprise the search for said plurality of containers in the image area preferably, the continuous main circle and arc corresponding secondary circle.

However, insofar as it has, for each container to be inspected, an overall image comprising two image areas each including an image of the ring surface and a possible burr, in two fields of observation various devices having two angles

different observation elevation, analysis of an image, for determining the presence of a burr at the location of the inner edge of the corresponding container, may comprise the search for said container, in the first zone and in the second image area, the first and second DC main circle and the first and second arc of a circle corresponding secondary to said container. This results, for the same container, information from the observation from two different viewing angles of elevation. This redundancy allows to confirm the presence of defects. This information is also possible, for example in a triangulation process to determine with greater accuracy and confidence information regarding the geometry of the burr, for example, its height and / or its radial position relative to the assumed location of the edge internal.

This crossing information obtained under the two peripheral fields of observation with different observation elevation angles can be booked in some containers, for example containers having particular defect characteristics. However, we can put this to good use not only for a given container, but possibly for a series of the same type container, for example having the same geometry.

In order to determine the presence or absence of a defect type burr for a given container, the method may include determining, in the image, a radial gap distance between an arc of circle and the main secondary circle nearest in an image area obtained by the invention. then we can determine the presence of a type of defect burr when said radial gap distance exceeds, for at least one spoke, a threshold value.

More particularly, in embodiments in which forming a first image area and a second image area, each comprising the image of the ring surface and possible burrs at the location of its inner edge, analyzing these image areas may include: - mark in the first image area, the first main circle and a first arc of a secondary circle and determining a first radial distance Dl between spacer both ; the radial spacing distance is, for example, to an arc, the maximum value of the radial distance between the two on the angular extent of the arc;

- mark in the second image area, the second main circle and a second circle arc secondary, and determining a second radial distance D2 distance between the two;

- mapping a first and a second arc of second circle found respectively in the first and the second image area as the two images, in the first and second peripheral field of observation, a same burr; such matching, or matching, can include establishing an algorithm that both arcs found each in a different area are image of the same object;

- determining by combining the radial spacing distances Dl and D2 measured for said first and second secondary arcs in both image areas ZI1, ZI2 to determine a value dependent on the relative height dZ of the burr relative in the ring surface;

- determining the presence of a burr when the value dependent on the relative height dZ exceed for at least one arc portion a threshold value.

In the embodiments which have been described above, each primary reflective surface directly reflects the rays of light towards the sensor 18. However, alternatively, could be provided between the one or more surface (s) primer (s) Brain 261, 262 and the sensor 18, at least one reference reflection surface. In this case, it is considered that the primary reflective surface 126 reflects the light rays indirectly towards the sensor 18. Such a surface deflection reflection may have a conical or frustoconical convex reflective surface, centered on the axis of installation, facing away from the axis of installation, flared downwards and of smaller diameter than the primary or reflection surfaces.

Illustrated in Figure 10 an inspection line 200 of containers 14 implementing a device 10 according to the invention. In the example illustrated, receptacles 14 are moved by a conveyor 210 which conveys the containers 14 in a direction of displacement, for example horizontal translation perpendicular to the theoretical central axis Al of the containers 14. In the example shown, the conveyor 210 includes a conveyor belt 212 on which the containers 14 are raised by their bottom surface, also called laying plane, with their theoretical central axis a arranged vertically. The conveyor may comprise a conveyor wheel moving the containers 14 along a circular path of travel, in particular in a horizontal plane. The conveyor 210 may also include guide means (not shown) cooperating with the side faces of the containers 14. The containers 14 thus have their surface ring 16 in a horizontal plane facing upward. The conveyor 210 leads the containers in the horizontal path below the device 10 according to invention, without risk of interference with the device 10. The device 10 may comprise a carrier, for example in the form of housing 230, including incorporating the sensor 18, the lens system 20, a light source 28, a first surface of primary beam 261 and optionally a second surface primary beam deflection 262. the housing 230 is arranged above the conveyor. Inside the housing 230, a device 10 according to the invention is arranged with its axis ΑΊ installation in a vertical position so that the observation field and the incident light beam are oriented downwardly towards the Z installation area that lies between the underside of the housing 230 and the conveyor belt 212. it is therefore understood that, at this inspection station, the conveyor 210 causes the container so that their theoretical central axis al coincides best with the axis of ΑΊ installation. When this coincidence, an image is acquired by the device 10, without requiring either handling the container or stop the conveyor. The image acquired by the device 10 may then be sent to a processing system 240, for example an image processing device and / or a display device and / or an image storage device, for example a system computer system comprising a computer. It is then possible to analyze the image thus acquired and to determine the presence or absence of a burr at the location of the inner edge of the ring surface 16 of the container 14.

The camera can be triggered to integrate a picture in synchronism with the movement of the articles, including to freeze the image at the time of alignment with the theoretical axis of Al ring with the axis of A'1 installation. The integration time is set short, for example less than 1 ms or 400ps, to reduce the risk of camera shake in pictures.

The light source may be pulsed, that is to say produce lighting for a brief period of flash type, for example less than 1 ms or 400μηΊ to reduce the buggy blur in images.

It can be anticipated that processing system 240 cooperates with or includes a control unit, which controls the light source and the camera, to synchronize with the movement of the articles.

The device and the method therefore have no physical contact with the container to control. A device according to the invention proves to be less expensive and space lower than the devices of the prior art, allowing easy installation in particular in a station or a line inspection items, inspection station or line which may comprise other devices for other controls, and the device according to the invention can thus be installed in particular in a production line where the containers circulating chain. Such a device thus allows control of containers line, whether on a production line of containers, or one of the containers processing line, or on a filling line, at high speed.

The device and method according to the invention can be implemented with a single two-dimensional photoelectric sensor, for example a single camera, and still provide reliable information about the presence or absence of a burr at the location of inner edge of the ring surface, this at once optical two-dimensional image acquired by the sensor directly, not from a plurality of optical images acquired separately.

The observation system according to the invention is presented here in preferred embodiments in which the reflective surfaces are mirrors. It is possible to obtain the same results by using optical elements type prisms also having tapered surfaces for example, causing total reflection. An optical element as defined in the invention may comprise a Fresnel lens. Such means also enable observation with the same values ​​of the angle there, and can be designed by these means telecentric or not comments.

The invention is not limited to the examples described and shown since various modifications can be made without departing from its scope.

CLAIMS
1 - A method of determining the presence of a glass burr at the location of an inner edge (15) of a ring surface (16) of a ring of a container (14), the surface of ring having theoretical geometry as a surface of revolution about a notional central axis (Al) of the type comprising:

- the illumination of the ring surface (16) of the container from above, with an incident light beam comprising light rays incident (RI) radial contained in at least a radial plane containing the central axis theoretical (Al), said radial rays incident parted nt of the theoretical central axis (Al) at their incidence on the ring surface, and some of the radial spokes of the incident light beam being reflected by specular reflection on the surface ring (16), as reflected rays (RR1, RR2);

- the formation, with the reflected rays, at least one image of the container finish surface, on a photoelectric sensor (18),

characterized in that:

- the incident light beam comprises light radial incident rays contained in radial planes distributed at 360 ° around the theoretical center axis (Al);

- the method comprises the observation of the ring surface (16) including the inner edge of the ring surface, from above, by an optical system (24, 261) according to a first peripheral field of view observed that the ring surface (16) of the first radial observation rays which are contained in radial planes containing the theoretical center axis (Al), which are distributed at 360 ° around the theoretical center axis (Al) the first peripheral field of view having a first angle of elevation (YI) with respect to a plane perpendicular to the theoretical central axis (Al), so as to collect on a two-dimensional photoelectric sensor in a first annular zone

of the sensor, to form a first region of two-dimensional digital image (ZI1):

o some of the incident light rays reflected along the first peripheral field of view (YI) by the ring surface, forming in said first image area (ZI1) annular, a main circle (CP1);

o and possibly reflected rays according to the first peripheral field of view (YI) by the inner edge of the ring surface or a burr at the location of the inner edge, forming in said first image area, the least a secondary circle arc (CS1) which is concentric to said main ring and radially offset with respect thereto;

and in that the method comprises:

o mark in said first image area, said main circle (CP1);

o mark in said first image area, a possible secondary arc of circle (CS1) which is concentric to said main ring and radially offset with respect thereto.

2 - Process according to claim 1, characterized in that, when displayed, according to the first peripheral observation field having the first angle of elevation (YI) of the stray rays reflected by a portion (S ') of a wall of the separate ring of the ring surface (16) and its internal edge formed in the first image area (ZI1), residual images, modifying the angle of elevation of observation (Yl ) into a value (Y2) different.

3 - Method according to claim 2, characterized in that the elevation angle of observation (γΐ, Y2) is modified by replacing at least one component (261, 262) of the optical system (24).

4 - Process according to any one of claims 1 to 3, characterized in that:

- the method comprises the observation of the ring surface (16) and the inner edge of the ring surface, from above, by an optical system (24, 262) according to a second peripheral field of view observed that the ring (16) of the second radial observation rays which are contained in radial planes containing the theoretical center axis (Al), which are distributed at 360 ° around the theoretical center axis (Al), second peripheral field of view having a second angle of elevation (γ2) relative to a theoretical plane perpendicular to the central axis (Al), but different from the first angle of elevation (γΐ) so as to collect on the same two-dimensional photoelectric sensor in a second annular zone of the sensor (ZI2) to form a second region of two-dimensional digital image (ZI2):

o some of the rays incident light reflected along the second peripheral field of view (Y2) by the ring surface, forming, in said second image area, a main circle (CP2);

o and possibly reflected rays according to the second peripheral field of view (Y2) by the inner edge of the ring surface or a burr at the location of the inner edge, forming in said second image area, the least a secondary circle arc (CS2), concentric with the main circle (CP2) and radially offset with respect thereto;

in that the method comprises:

o mark in said second image area (ZI2), the main circle (CP2);

o mark in said second image area (ZI2), a possible secondary arc of circle (CS2) concentric with the main circle (CP2) and radially offset with respect thereto.

5 - Determination method according to claim 4, characterized in that it comprises:

• the simultaneous observation by the optical system (24, 261, 262), as the first peripheral observation field having the first observation angle (γΐ) and according to the second peripheral observation field having the second angle observation (Y2);

• setting by relative translation along the theoretical central axis of a relative position of the optical system (24) with respect to the ring surface (16) of the container, so as to allow the formation of a two-dimensional image of the surface ring of the container and its internal edge is in the first image area (ZI) corresponding to the observation according to the first peripheral field of view (YI) in the second image area (Z2) corresponding to observation device according to the second field of view (Y2);

• looking for a main circle (CP1, CP2) then at least an arc of secondary circle (CS1, CS2) or in the first image area (QYou) in the second image area (ZI2 ).

6 - Determination method according to claim 4 or claim 5, characterized in that it comprises:

- the simultaneous observation of the ring surface (16) including the inner edge of the ring surface by the optical system (24, 261, 262), as the first peripheral field of view and according to the second field observation device;

- the simultaneous formation, from reflected rays collected in the first and second peripheral fields of view through the optical system (24, 261, 262), a two-dimensional image of the container finish surface and the inner edge simultaneously in both the first image area (QYou) corresponding to the observation according to the first peripheral field of view (γΐ) and the second image area (ZI2) corresponding to the observation device according to the second field of view (Y2) on the same two-dimensional sensor (18), the first image area and the second image area being disjoint.

7 - Process according to any one of claims 5 or 6, characterized in that it comprises:

- selecting, for at least a series of similar containers, of a preferred image area of ​​the first and the second image area (ZI1, ZI2);

- searching for said plurality of containers, preferably in the image area, the DC main circle and arc corresponding secondary circle.

8 - Method according to one of Claims 4 to 7, characterized in that it comprises the search for at least one container in the first image area (ZI1), a first main continuous circle (CP1) and a first secondary arc of circle (CS1) corresponding to said container and in the second image area (ZI2), a second main continuous circle (CP2) and a second arc of a circle secondary (CS2) corresponding to the said container.

9 - Method according to one of Claims 4 to 7, characterized in that it comprises the search, for each container of at least one series of containers of the same type in the first image area (ZI1), d a first continuous main circle (CP1) and a first arc of a secondary circle (CS1) corresponding to a container, and in the second image area (ZI2), a second main continuous circle (CP2) and a second arc of a secondary circle (CS2) corresponding to said container.

10 - Determining method according to any one of the preceding claims, characterized in that the optical system (24) comprises a first primary reflection surface (261), the first primary reflection surface (261) being a surface of revolution centered on the theoretical center axis (Al) and arranged to directly or indirectly reflect the light rays, from the ring surface (16) according to the first peripheral field of view (γΐ) towards the sensor (18).

11 - Determining method according to any one of claims 2 to 10, characterized in that the optical system (24) includes a second primary reflection surface (262), the second primary reflection surface (262) being a surface of revolution centered on the theoretical center axis (Al) and arranged to directly or indirectly reflect the light rays, from the collar surface in the second peripheral field of view (Y2) in the direction of the sensor (18).

12 - Determining method according to any one of the preceding claims, characterized in that the formation of the two-dimensional image area (ZI1, ZI2) includes the optical forming a two-dimensional image (CP1, CP2) continues to complete and 360 ° around the theoretical center axis (Al) of the ring surface (16) on the same sensor (18).

13 - Determining method according to any one of the preceding claims, characterized in that the method comprises determining the presence of a burr when a radial distance (Dl, D2) spacer between a secondary circle arc (CSl, CS2) and the nearest main circle (CP1, CP2), exceeds for at least one spoke, a threshold value.

14 - Determining method according to any one of claims 6, 8 or 9, characterized in that the method comprises:

- mark in the first image area (ZI1), a first main circle (CP1) and a first arc of a secondary circle (CSl) and determining a radial distance (Dl) between both ;

- mark in the second image area (ZI2), a second main circle (CP2) and a second arc of a secondary circle (CS2), and determining a radial distance (D2) between the two ;

- mapping the first and second arc of a circle secondary found respectively in the first and the second image area as the two images, according to the first and second peripheral field of view, the same burr;

- determining by combining the radial distance spacer (Dl, D2) measured for said first and second secondary arcs in both image areas {211, ZI2) to determine a value dependent of a relative height ( dZ) of the burr relative to the collar surface;

- determining the presence of a burr when the value exceeds, for at least an arc portion a threshold value.

15 - An apparatus for inspecting the presence of a glass burr at the location of an inner edge of a ring surface (16) of a container (14), the ring surface having a geometry as theoretical surface of revolution about a notional central axis (Al) of the type wherein the device (10) has an installation area (Z) with a ring surface (16) of a container to be inspected, this area installation having an installation axis (A'1) of the type comprising:

an illumination system (28, 28 ') arranged above the installation area and capable of providing an incident light beam comprising radial spokes contained in at least a radial plane containing the axis of installation (A' 1), said radial rays incident away from the axis of installation (ΑΊ) at their incidence on the collar surface;

a sensor (18) connected to an image analysis unit;

an optical system (24, 261, 262) arranged above the installation area interposed between the installation area and the sensor (18) and capable of forming on the sensor (18) an image (CP1, CP2) of the ring surface (16) to be inspected (14) disposed in the installation area;

characterized in that:

- the sensor is a two-dimensional image sensor;

- faisceau the terrace is a funny faisceau lumineux comprenant des rayons incidents radiaux Contenus dans des plans radiaux on the alignment of installation (Dreaming) and répartis to 360 ° around the alignment of installation (ΑΊ);

the optical system comprises at least a first primary reflection surface (126) in an upstream field of vision of the sensor, the first primary reflection surface (126) being a surface of revolution centered about the installation axis (ΑΊ) facing the axis of installation, and arranged to reflect, directly or indirectly, towards the sensor (18) light rays coming from the installation area along radial planes containing the axis of installation (ΑΊ) and according to a first peripheral field of view having a first angle of elevation (YI) with respect to a plane perpendicular to the central axis of installation (ΑΊ);

the device comprises at least one second primary reflection surface (262) in the upstream field of view sensor (18), the second primary reflecting surface being a surface of revolution centered on the axis installation facing the installation axis and arranged to reflect directly or indirectly towards the sensor (18) light rays coming from the installation area along radial planes containing the axis of installation (ΑΊ) and in a second field of observation device having a second angle of elevation (Y2) with respect to a plane perpendicular to the central axis of installation (ΑΊ), said second observation elevation angle being different from the first elevation angle observation, the first primary surface and the second primary surface of reflection both being in disjoint portions of the upstream line of sight of the sensor; and

the first primary reflection surface (261) and the second reflection surface (262) determining for the sensor (18) respectively a first portion downstream of sight (CAV1) and a second portion downstream field of view (CAV2) which overlap in the inspection area.

16 - Device according to any one of claims 15 to 18, characterized in that the first primary reflection surface (261) and the second primary reflection surface (262) are tapered to angles different top.

17 - Device according to claim 16, characterized in that the first primary reflection surface (261) and the second primary reflection surface (262) are superposed and have a common circular edge corresponding to a lower edge of the upper surface and an upper edge of the lower surface.

18 - Device according to claim 16, characterized in that the first primary reflection surface (261) and the second primary reflection surface (262) are offset axially by being axially separated to a non-zero axial distance between a lower edge of the upper surface and an upper edge of the bottom surface.

19 - Device according to one of claims 15 to 18, characterized in that the first primary reflection surface (261) and the second primary reflection surface (262) are positioned to ensure that:

- considering a point (Sref) of the ring surface;

- whereas a first optical path (RR1) followed, from such point (Sref) and the sensor (18) by an incident ray reflected by the point considered in the ring surface according to the first peripheral field of view (γΐ) then reflected towards the sensor on the first primary reflection surface (261); and

- whereas a second optical path followed between the point considered and the sensor by a second incident ray reflected in the considered point of the ring surface as the second peripheral field of view (Y2) and reflected towards the sensor on the second primary reflection surface (261);

the difference in length between the first optical path and second optical path is less than the depth of field value of the formed image when the optical system (24) is developed on the collar surface (16).

20 - Device according to any one of claims 15 to 19, characterized in that the first primary reflection surface (261) and the second primary reflection surface (262) are, according to a radial plane containing the central axis installation (ΑΊ), tangent to an ellipsoid of which a fireplace is the center of a lens system the entrance pupil (20) of a camera (19) comprising the image sensor (18) and whose second focal point is arranged on the central axis of installation (ΑΊ) at the ring (12) of the container to be inspected.

21 - Device according to any one of claims 15 to 20, characterized in that the primary reflection surface (261, 262) is flared in the direction of the axis of installation (ΑΊ) and has a large diameter and a small diameter both greater than the maximum diameter of the ring surface (16) to be inspected.

22 - Device according to any one of claims 15 to 21, characterized in that the primary reflection surface (261, 262) is a frustoconical surface which faces the axis of installation (A'I).

23 - Device according to claim 15 to 22, characterized in that the primary reflection surface (261, 262) indirectly reflects the light rays towards the sensor (18), and in that the device comprises, between the primary surface reflection (261, 262) and the sensor (18), at least one deflection reflection surface.

24 - Device according to claim 23, characterized in that the reference reflection surface includes a surface of revolution facing away from the axis of installation (ΑΊ) so as to return the rays towards the sensor (18 ).

25 - Device according to any one of claims 15 to 24, characterized in that between the sensor (18) and the primary reflection surface (261, 262), the optical system is telecentric (20).

26 - Device according to any one of claims 15 to 25, characterized in that the incident beam device, comprising, in a same radial plane, non-parallel radial spokes.

27 - Device according to any one of claims 15 to 26, characterized in that the illumination system comprises a light source (28) power plant at least partially contained in a cylindrical envelope of revolution having as its axis the axis of Installation (ΑΊ) diameter and the diameter of the inner edge (15) of the ring surface (16) to be inspected.

28 - Device according to any one of claims 15 to 26, characterized in that it comprises a light source (28 ') is circularly annular, centered on the axis of installation (A'I) which generates rays radial light incidents that affect the ring surface (16) after having intersected the axis of installation (A'I).

29 - Device according to any one of claims 15 to 28, characterized in that the device (10) comprises a support (230) supporting the sensor (18), the lens system (20), a primary reflection surface (261 , 262), a light source (28, 28 ') and optionally a reference reflecting surface (32).

30 - Line Inspection (200) of containers (14) having a ring surface (16) of the type in which containers (14) are moved on a conveyor line by a conveyor (210) which conveys the containers ( 14) in a direction of horizontal movement perpendicular to a notional central axis (Al) of the containers 14, which thus have their ring surface (16) in a horizontal plane facing upward, characterized in that the installation comprises a device ( 10) according to any one of claims 15 to 28, which is arranged on the installation with its axis of installation (ΑΊ) in vertical position, so that the observation field and the incident light beam are oriented down, to the installation zone (Z) located between the device and a conveying member of the conveyor (212).

31 - Line Inspection Unit (200) according to claim 30, characterized in that the conveyor (210) causes the container so that their theoretical central axis (Al) coincides with the axis of installation (ΑΊ) and when this coincidence, an image is acquired by the device (10) without contacting the device (10) with the container (14).