DESC:SYSTEM AND METHOD FOR DETECTION OF DRAW LINES ON DRAWN TUBE OF SHOCK ABSORBER

Field of the invention

The present invention relates to drawn tubes of a suspension system of an automobile and more particularly, to an automatic vision system for detection of draw-lines on drawn tubes of shock absorbers and a method therefor.

Background of the invention

A pressure tube of a shock absorber when made by passing a metal or a rod through a mandrel or wedge is known as drawn tube. Generally, the process of drawing the tube creates lines along an axis of drawing called as draw lines. These draw lines on the drawn tube are not easily visible to naked eyes.

Prior art systems and methods for detection of draw lines or cracks on the drawn tube of the shock absorber are based on magnetic flux wherein the electrically charged particles are deposited on the drawn tube. These deposited particles get oriented in a particular manner to detect the possible draw lines / cracks. This visual method is extremely slow, unreliable due to manual intervention and is not environment friendly.

Accordingly, there is a need of an automatic vision system and a method for detection of draw lines on drawn tubes of shock absorbers that overcomes the above mentioned drawbacks of the prior art.

Object of the invention
An object of the present invention is to detect draw lines in a fast, reliable and environment friendly manner.

Summary of the invention

Accordingly, the present invention, in an aspect, provides a system for detection of draw lines on a drawn tube of a shock absorber. The system comprises a moving mechanism, an imaging device, a processing module and a comparator module.

The moving mechanism is adapted for longitudinal movement and rotation of the drawn tube. The imaging device is adapted for scanning full surface of the drawn tube for capturing at least one image of the draw lines thereon. The processing module is adapted to process the at least one captured image into a comparable form. The comparator module includes at least one pre-stored image of a normal drawn tube fed therein. The comparator module is adapted to compare the at least one captured image with the at least one pre-stored image to detect draw lines on the drawn tube and further differentiate between full draw lines, partial draw lines, surface scratches and dents on the drawn tube to generate a feedback in response thereto.

In another aspect, the present invention provides a method for detection of draw lines on a drawn tube of the shock absorber.

Brief description of the drawings

The objectives and advantages of the present invention will become apparent from the following description read in accordance with the accompanying drawings wherein,
Figure 1 shows a system for detection of draw lines on a drawn tube of a shock absorber, in accordance with the present invention;

Figure 2 shows a flow chart illustrating a method for detection of draw lines on the drawn tube of the shock absorber, in accordance with the present invention; and

Figures 3a-3d show different types of draw lines detected on the drawn tube, in accordance with the present invention.

Detail description of the invention

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiment.

The present invention provides a system for detection of draw lines on a drawn tube of a shock absorber. The system and the method of the present invention detect draw lines in a fast, reliable and environment friendly manner.

The present invention is illustrated with reference to the accompanying drawings, wherein numbers indicated in the bracket represent the components of the invention throughout the description.

Referring now to figure 1, in an aspect, there is shown a system (50) (herein after ‘the system (50)’) for detection of draw lines on a drawn tube (60) of a shock absorber (not shown) in accordance with the present invention. Specifically, the system (50) is an automatic vision system based on a digital technology and comprises a moving mechanism (not shown), an imaging device (10), a processing module (20) and a comparator module (30).

The moving mechanism is responsible for longitudinal movement as well rotation of the drawn tube (60). In an embodiment, the moving mechanism is a lathe in which the drawn tube (60) is held and rotated. The drawn tube (60) is rotated to check the draw lines all around the drawn tube (60) on the full length and circumference thereof.

The imaging device (10) is specially developed and programmed to scan full surface of the drawn tube (60) for capturing at least one image (herein after ‘the image’) of draw lines on the drawn tube (60). In an embodiment, the imaging device (10) is a camera. However, it is understood that any other suitable device known in the art can be used as the imaging device (10) as per various alternate embodiments of the present invention.

The processing module (20) is a high resolution and high speed processing module (20). The processing module (20) is adapted for processing the captured and scanned image into a comparable form for example data form.

The comparator module (30) is adapted for performing confirmation of the draw lines / crack and further differentiates between the draw lines and the surface scratches. The comparator module (30) includes at least one pre-stored image (herein after ‘the pre-stored image’) of a normal drawn tube fed therein. The captured image is directly compared with the pre-stored image by the comparator module (30). If anything abnormal, the comparator module (30) gives a feedback as rejected. The comparator module (30) differentiates between full draw line (figure 3a), partial draw line (figure 3b), surface scratches resulting from a material defect (figure 3c) and dents (figure 3d) on the drawn tube (60). Based on the detection, a feedback about the draw lines is provided by the comparator module (30).

Referring now to figure 2, in another aspect, there is shown a method (200) for detection of draw lines on the drawn tube (60) of the shock absorber in accordance with the present invention. Specifically, the method (200) is described in conjunction with the system (50) of the present invention. The method (200) begins at step (110).

At step (120), the method (200) involves moving and rotating the drawn tube (60) by the moving mechanism. At step (130), the method (200) involves capturing the image of the drawn tube (60) by the imaging device (10). At step (140), the method (200) involves processing the captured image into the comparable form by the processing module (20). At step (150), the method (200) involves comparing the captured image with the pre-stored image of the normal drawn tube to detect draw lines on the drawn tube (60) and further differentiate between full draw lines (refer figure 3a), partial draw lines (refer figure 3b), surface scratches (refer figure 3c) and dents (refer figure 3d) on the drawn tube (60) by the comparator module (30) and generating a feedback relating thereto. The method (200) stops at step (160).

Advantages of the invention

1. The system (50) is environment friendly.
2. The system (50) and the method (200) are fast in decision making.
3. The system (50) and the method (200) are fully automated.
4. The system (50) and the method (200) provide differentiation between full, partial draw lines, surface scratches and dents.

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention.


,CLAIMS:We claim:

1. A system (50) for detection of draw lines on a drawn tube (60) of a
shock absorber, the system (50) comprising:
• a moving mechanism adapted for longitudinal movement and rotation of
the drawn tube (60);
• an imaging device (10) adapted for scanning full surface of the drawn tube
(60) for capturing at least one image of the draw lines thereon;
• a processing module (20) adapted to process the captured the at least one
image into a comparable form; and
• a comparator module (30) having at least one pre-stored image of a
normal drawn tube fed therein, the comparator module (30) adapted to compare the at
least one captured image with the at least one pre-stored image to detect draw lines
on the drawn tube (60) and further differentiate between full draw lines, partial draw
lines, surface scratches and dents on the drawn tube (60) to generate a feedback in
response thereto.

2. A method for detection of draw lines on a drawn tube (60) of a shock absorber, the method comprising:
• moving and rotating the drawn tube (60) by a moving mechanism;
• capturing an image of the drawn tube (60) by an imaging device (10);
• processing the captured image into a comparable form by a processing
module (20); and
• comparing the captured image with a pre-stored image of a normal drawn
tube to detect draw lines on the drawn tube (60) and further differentiate between full
draw lines, partial draw lines, surface scratches and dents on the drawn tube (60) by a
comparator module (30) having the pre-stored image fed therein to generate a
feedback in response thereto.