NONINTRUSIVE INSPECTION METHOD AND SYSTEM
This invention relates to a nonintrusive inspection method and system, that radiographics containers, vehicles and train carriages without having to break seals, open containers or physical control.
The invention may be used for the scanning of vehicles, to create a radiography, that can be evaluated and from which to result the nature and quantity of the transported merchandise, to track down smuggling attempts or illegal transports of forbidden or undeclared products (drugs, explosives, weaponry, etc), for antiterrorist protection, by scanning all vehicles that have access in restricted areas, like airports, maritime and fluvial harbors, border crossing points, access to secure buildings, military bases, etc.
With the purpose of nonintrusive control several scanning methods are known, for which the following radiation sources:
Gamma radiation sources, generated naturally by double encapsulated radioactive material like:
Cobalt, Cesium, etc.
X-ray generators or linear accelerators of X-ray, gamma radiation and neutrons
The nonintrusive inspection system principle requires the irradiation of a detector area, linearly placed in front of a thin fan-shaped curtain of collimated radiation through which the scanned object is relatively moved. The detectors' electrical signals are analogically/digitally processed, to generate, line by line, a radiography to be displayed on a PC monitor. The relative movement of the scanned object is realized by moving the object relative to a fixed scanner, or by moving the scanner relative to a fixed object. The operation of the entire system is realized from a control cabin, placed close to the scanner, cabin for which extensive radiation shielding is mandatory.
This method has the drawback that it exposes the operators to the professional irradiation risk.
Currently, several nonintrusive scanning systems are known that include the technologies presented previously. One of these is the mobile imaging system with gamma radiation, GaRDS, manufactured by the American company RAPISCAN SECURITY PRODUCTS Inc. GaRDS, like all other mobile scanning systems, that are presently known, have the operator's cabin mounted on the chassis, exposing the crew of the system to the professional and accidental irradiation risks, risks eliminated by the present invention by building the operator's cabin on a mobile, tow able unit, that is placed outside of the exclusion area during scanning procedures, and controls all processes from distance by radio. Another major difference is that the known systems, including GaRDS, need a driver to operate the scanning unit, need eliminated in the present invention by implementing a subsystem for the automated control of speed and steering.
Other disadvantages of the known systems consist of the fact that they are heavy, being installed on vehicles capable of carrying heavy loads, with two up to four axles, necessary to bear the weight of the components and of the counterweights that compensate the tipping moment generated by the boom holding the radiation source at a lateral distance of minimum 4 meters away from the detectors area.
The operating of the known systems is very complicated, needing a minimum three person per shift crew, operator, driver and external supervisor, the last having the responsibility to direct the traffic of the vehicles that are to be scanned in the scanning area, as well as to prevent intrusion in the exclusion area, where the danger of irradiation exists.
The technical issue that is dealt by the present invention is the realization of a nonintrusive inspection method and system, that eliminates entirely the professional irradiation risk, by removing the operators cabin (the control centre) from the exclusion area and eliminating the need of a driver and external supervisor, by automation and remote operation of all processes deployed in the exclusion area and the limitrophe area. By implementing these automated processes, the reduction of personnel to one person per shift is possible.
The rjonintrusive inspection method, according to the invention, eliminates the disadvantages mentioned above by that the vehicle that is to be scanned has access in the exclusion area through an automated traffic management subsystem that automatically commands the functioning of the barriers and of the entry/exit semaphores. The vehicle is placed in a marked spot, before its driver left the exclusion area (where there is the irradiation risk), then the protection of the exclusion area is activated, followed by the initiation of the scanning process by remote commands to the mobile scanning unit, when the radiation source is activated and the slow movement of the mobile scanning unit is started. This unit is moving on a parallel trajectory to the scanned vehicle, framing it. The movement of the mobile unit is automatically controlled by on-board electronic and informatics modules, connected with the control centre in a local area network, through radio modems, centre from which it receives commands, and towards which it sends in real time status information and specialized data. The stopping of the scan is performed automatically in the following situations, when the detector boom has passed the extremity of the scanned vehicle and the detectors receive the maximum level of radiation, at the end of the programmed scan length, when the protection limiter of the movement is triggered, when the protection of the exclusion area has been breached, when the proximity sensors have been triggered indicating dangerous distance between the detector boom and the scanned vehicle, when obstacles close to the guiding paths have been automatically detected by sensors placed on the mobile scanning unit. The stopping of the scanning process can be manually commanded by the operator in any moment. During this stage of the process, the image resulted from scanning the vehicle is displayed on the operator's monitor and at the end of the stage the protection of the exclusion area is automatically deactivated, and the vehicle may leave the scanning area. The mobile scanning unit moves back to the start position and the scanning cycle may be restarted.
The system that implements the method presented above, consists of a mobile scanning unit installed on an truck chassis, onto which a boom with detector areas specific to the radiation type used is mounted, a source boom carrier of a radiation source is mounted, the unit being autonomous and having subsystems for the automated control of speed and steering, a positioning synchronization subsystem and a hydraulic propulsion subsystem to realize a precise slow motion of the scanning unit. The system includes also a mobile control centre, that is placed outside of the scanning area and that remotely manages all processes, including a
subsystem for acquisition, processing, storage and displaying of scanned image. The system also includes an exclusion area protection subsystem, an automated traffic management subsystem and a computer management subsystem.
The mobile scanning unit has a detector boom made up of the upper detector area mounted on a steel prop that can pivot round an axle, in a bearing solidary with a supplementary chassis and the lower detector area, the last being mounted independent in a oscillatory dogging, the two areas having separated folding systems during transport, but with unitary functionality during scanning operation.
The detector boom is made up of five segments oriented under different angles and is made out of light alloy assembled in the form of the letter "T".
The subsystem for the automated control of speed and steering of the mobile scanning unit is built with an electric motor that drives the steering column and an electronic command module. The subsystem receives information about the unit's relative position to the scanned object. The positioning information are received through some hardware/software sensors placed on the mobile scanning unit.
The hydraulic motion subsystem that drives the chassis in slow motion, is made out of a gearbox for combined drive subsystem that has a revolution sensor, a hydraulic motor, a variable flow capacity hydraulic pump controlled by an electronic module, commanded by an automated motion control specialized software application.
The automated traffic management subsystem is endowed with some barriers and traffic lights commanded by radio, directly by a specialized software application and the exclusion area protection subsystem is made out of some motion detection active sensors, a control module for the sensors' status and an emergency automated radiation source shutdown module in the case that the exclusion area has been breached.
The subsystem for acquisition, processing, storage and displaying of scanned image is made out of some preamplifier modules to which the detectors are connected, some multiplexer modules, some analogue-digital converters, some microcontrollers, a CAN bus, some CAN modules, a CANi communication interface with a processing unit that runs a specialized software application, connected through wireless LAN to another processing unit that runs another specialized software application in order to display on a monitor the resulted radiography.
The invention has the following advantages:
elimination of professional irradiation risk of the operators as well as the risk of accidental
irradiation of the possible intruders in the exclusion area;
the reduction of the personnel from minimum three per shift, to one person per shift;
increased system mobility, flexibility and manoeuvrability ;
increased automation;
increased productivity, higher number of scan vehicle over time unit, by automating processes and
diminishing the idle time by computer managing the processes;
obtainment of a variable scanning speed, adjustable for maximum throughput or maximum
penetration with a good quality image without geometric distortion;
precise control of speed and travelled distance in a set time range;
the preservation of the dynamic performances of the chassis in "transport mode";
significant reduction, with over 20% of the system's total weight with positive effects in the
reduction of the tipping moment and the torsion stress within the chassis;
significant reduction, with over 30% of specific consumptions of energy and fuel;
capability of a later analysis of the functioning parameters and/or possible undesired events by
implementing a "black box", similar to those used in aviation, that automatically records all
commands, feedback and system's functioning parameters.
Further is presented an example of implementing of the invention in connection with the figures from 1 to 9 that describe:
fig. 1, perspective view of the nonintrusive inspection system, according to the invention, placed
within the exclusion area;
fig.2, nonintrusive inspection system diagram, according to the invention;
fig. 3, overview of the chassis in transport mode;
fig. 4, view from the back of the mobile units in scanning position;
fig. 5, schematics overview of the driving train when using mechanical direct drive
fig. 6, schematic overview of the driving train when using the hydraulic pump of the gearbox for
combined drive interpolated between the output shaft of the gearbox and the input shaft of the rear
axle;
fig. 7, schematic lateral view, of the gearbox for combined drive
fig. 8, subsystem for acquisition, processing, storage and displaying of scanned image diagram;
fig. 9 diagram of the automated control of speed and steering
The nonintrusive inspection method has the following steps:
the vehicle that is to be inspected is brought up to the entry barrier in the scanning area;
the driver of the vehicle steps out of the vehicle and hands over the transport's documents; - entry in the scanning area is allowed, the entry barrier is raised and the entry traffic light is
switched on green, and the exclusion area protection subsystem is deactivated;
the driver positions the vehicle in the scanning area, in the marked spot and leaves the exclusion
area;
the exclusion area protection subsystem is activated;
the operator, initiates the scanning process from the control centre by radio transmitting the
command to the mobile scanning unit;
the radiation source is activated and the slow motion of the scanning unit is initiated. The mobile scanning unit moves along the inspected vehicle, framing it. The speed of the unit is controlled automatically by electronic and informatics modules placed on board. These modules are radio connected, through radio modem in the LAN with the control centre from which they receive commands and to which they send feedback; the scan is automatically stopped in the following situations:
o if the detector boom passed the inspected vehicle's extremity, so the imaging system
receives a series of white lines meaning maximum level of radiation on all detectors; o at the end of the programmed scanning length; o if the length limitation system has been triggered; o if the protection of the exclusion area has been breached; o when the distance between the detector boom and the inspected vehicle is dangerously
small, the proximity sensor that measures that distance triggers; o on the automatic detection of obstacles in the proximity of the mobile scanning unit, by the sensors placed in the front and back of the mobile unit; all documents regarding the transport are scanned and stored in a database; the radiography of the vehicle is displayed on the monitor in the control centre; at the end of the scanning phase, the protection of the exclusion area is deactivated; the driver of the inspected vehicle receives back the transport's documents; the exit barrier raises, the exit traffic light turns green and the vehicle leaves the area; the exit barrier returns and the cycle can be restarted;
a file that contains the radiography and the real image of the vehicle as well as copies of all documents concerning the transport is created and stored with an unique identity. The nonintrusive inspection system, according to the invention, is a mobile ensemble of radioactive scanning, installed on an autonomous chassis 1, light with a metallic detector boom 2 built on it, made of steel and light alloy, composed of five angular segments, articulated and driven by hydraulic cylinders. On the boom 2, there is an upper detector area 3 and a lower detector area 4, therefore the metallic boom 2 will be referred from this point forward detector boom. On the autonomous chassis 1, referred from this point forward as mobile scanning unit, there is another segmented metallic boom 5 referred from this point forward as source boom, onto which far end there is a radiation source 6 attached.
The metallic detector 2 and source booms 5, are connected to a boom positioning subsystem 7 which controls the position of each segment of each boom in scanning mode, transport mode and is managing the deployment of the booms between modes.
On the mobile scanning unit 1, a gearbox for combined drive subsystem 8 is mounted, onto which a hydraulic motion subsystem 9 is mounted for movement of the mobile scanning unit 1 with low speed,
electronically controlled, during scan. For following the scan objects' contour during scan, the nonintrusive iitspection system has a subsystem for the automated control of speed and steering 10.
A subsystem for acquisition, processing, storage and displaying of scanned image 11, receives signals and data from the radiation detection areas mounted on the detector boom 2, digitizes the data and transmits it, through the radio modem, to a mobile control centre, where a radiographic image of the scanned object is created. This image is analysed by the operator and stored electronically.
Because in the scanning area a radiological protection against accidental irradiation of possible intruders must be insured, an exclusion area protection subsystem is provided, which establishes a rectangular excluding area a and is connected with an automated traffic management subsystem 14, which administrates the peripherals for access control in the scanning and limitrophe area, of the vehicles which are to be scanned. The peripherals are an entry barrier 15, an exit barrier 16, an entry semaphore 17 and an exit semaphore 18.
A computer management subsystem 19, commands and controls from distance all the subsystems of the entire assembly: the steering, engine revolution and the position of the mobile scanning unit 1 in the exclusion area a, and all others peripherals connected in the system, according to the invention, communicating with all these in a wireless LAN.
In an implementing variant, all physical components of the computer management subsystem 19, and the operator post are installed in the mobile control centre 12, which is towed during transport by the autonomous chassis, and is placed outside the exclusion area a in the scanning mode.
In another implementing variant, all physical components of the computer management subsystem 19, and the operator post are contained in an ultra portable command and control centre 20 contained in a rugged case for military applications, where mobility and portability are key survival issues.
The subsystem for the automated control of speed and steering 10 receives information from some proximity sensors 21 regarding the distance between the mobile scanning unit 1 and the scanned vehicle.
The inspection system, according to the invention, mounted on the mobile scanning unit 1 has two physical modes, "scanning mode" and "transport mode". The transition from one mode to another is done by the boom positioning subsystem 7 operating a set of hydraulic cylinders 22 which are reconfiguring the components' positions, based on information retrieved from a set of positioning sensors 23 of the hydraulic cylinders 22.
In the "transport mode" the detector boom 2 and source boom 5 are folded along the autonomous chassis 1 in order to assure the legal overall dimension for transport on public roads and a good repartition of the load on the axles. The components of the automated traffic management subsystem 14 are raised on the autonomous chassis 1 platform, in special containers, and mechanically ensured. The mobile control centre 12 is towed by the mobile scanning unit 1 and the gearbox for combined drive subsystem 8 is switched in transport position, with direct shaft connection between a gearbox 24 and a motor axle 25.
In the "scanning mode" the detector boom 2 and source boom 5 are laterally extended, to the right, almost perpendicularly on the axle of the autonomous chassis 1. The barriers 15,16 and semaphores 17,18 are
pkced in the entrance and exit points of the exclusion area a and the mobile control centre 12 is placed near the entrance in this area. The gearbox for combined drive subsystem 8 is switched to "scanning mode", meaning the shaft output from the gearbox 24 is moving a hydraulic pump 26, joined with a hydraulic motor 27, which is connected directly, mechanically with the motor axle 25.
The autonomous chassis of the mobile scanning unit 1 must be one homologated according to the international standards to allow transport on public roads without needing a special transport authorization. The autonomous chassis has a supplementary chassis 28, made of steel, on which all the components of the mobile scanning unit are joined, respectively, the two areas 3 and 4 of the detector boom 2, the enclosed parts of the hydraulic system as: oil tank, the distributors, adjusting and securing circuits, the lockers with electrical and electronic circuits, the lockers in which the barriers, semaphores are transported. Some of these assemblies do not figurate, because are well known and unclaimed components.
The detector boom 2 is fixed on a steel prop 29 of the source boom 5 that can pivot on a axle, in a bearing 30 solidary with the supplementary chassis 28. On this prop 29 the upper part of the detector boom 2 is mounted, in an oscillatory joint, made from a five segment, "T" shape, light alloy structure.
The preferred constructive solution is the use of one detector boom 2 made of five segments. The vertical segment is constructed in two parts: the lower detector area 4, mounted independently, laterally to the right, on the supplementary chassis 28, in an oscillatory fix in a perpendicular bolt on the longitudinal axle of the chassis and the upper detector area 3, mounted on the pivoting steel prop 29. The strength structure of the detector boom 2 is made of light alloy sheet, assembled in "T" shape.
Depending on the chosen radiation source, the system, according to the invention, will include the detector areas 3 and 4, in order to transform the radiation received in electrical signals which are then processed and transformed in radiographic images of the scanned object. For an X-ray source hybrid detectors with scintillation crystals and photodiodes or monolithic detectors with jointed load circuits will be used. For a gamma radiation source hybrid detectors with scintillation crystals jointed with photomultiplier tubes will be used. For a neutron source hybrid detectors with scintillation crystals having a very fast response and great efficiency jointed with photomultiplier tubes will be used.
All hybrid detection systems are using photodiodes or photomultiplier tubes that have maximum sensibility for the visible band to which the scintillation crystals have a maximum response to the type of radiation used.
The placement of the detectors may be done depending on the combination source-detector and the constructive variant of the detectors, on a line or two or in matrixes of different forms.
The radiation source 6 is fixed onto the source boom 5, in a way that a radiation curtain b to be collimated on the detector area 3 and 4.
In the "transport" mode the radiation source 6 is placed automatically on the platform of the chassis 1 in a specially made container according to the radiological security standardizations.
The positioning synchronization subsystem 7 is used for synchronisation of the speed and position of tire source robot 5 with the chassis 1. The subsystem 7 is made of one hardware/software module Mir, placed on the source robot 5 and another hardware/software module Mis placed on the chassis 1; the modules exchange data about the speed and the position in the scanning lane. Beside these modules Mir and Mis, there are another two hardware/software modules M2r and M2s that are permanently monitoring the position of the two mobiles, the autonomous chassis 1 and the source robot 5 and sends them commands.
The boom positioning subsystem 7 monitors the position and sends commands to every actuator of each segment of the source boom 5 and detector boom 2. The position of every segment of the booms in "transport mode", "scan mode" and intermediary positions is established by the boom positioning subsystem 7 in an automatic manner, following a macro command from the operator.
The radiation source 6 used in the nonintrusive inspection system, according to the invention, may be made of double encapsulated radioactive material, X-ray generator or linear accelerator for gamma ray or neutrons.
In an implementing variant, the radiation source is made out of double encapsulated radioactive material, for example Co60. The choice of the radioactive material - in the case of Co60 the energy is 1.3 MeV, and source activity of 1 Currie - is made depending on the desired penetration and the available exclusion area a dimensions. The capsule containing the radioactive material is surrounded by a thick screen that absorbs the radiation when the source is not activated.
The sizing of the screen is made in accordance with international standards. In this screen a fan-shape cut with an angular opening of 80 degrees is made, in order to collimate a radiation curtain b at a width of approximately 18 cm on the detector areas 3 and 4, having placed the radiation source 6 at a distance of five meters from the detector boom 2. The activation of the source 6, will be made through a pneumatic or electric actuator system.
The system used, must ensure the automatic retreat of the radioactive capsule in order to stop the radiation, if the actuator would be defective. The activation of the source 6, is signalled acoustically and optically in order to warn the operator and any one of the presence of radiation in the exclusion area a.
The hydraulic propulsion subsystem 9, allows the chassis 1, to move with low speed between 0.1-1 m/sec. The subsystem 9, uses the gearbox for combined drive subsystem 8, mounted on the chassis 1, between the driver shaft 31, of the gearbox 24, and the driving shaft 32, of the motor axle 25. This gearbox 8, allows the switch of the mechanical power output from the driving shaft 31 of the gearbox 24, directly to the motor axle 25, in "transport mode" or to the hydraulic pump 26, in "scanning mode".
In "transport mode", the driving shaft 31, of the gearbox 24, is connected directly and mechanically in a 1:1 ratio, through the driving shaft 32, to the motor axle 25, without modifying the power, torque or speed of the chassis 1.
In "scanning mode", the driving shaft 31, of the gearbox 24, is connected mechanically in a set ratio with the hydraulic pump 26. The flow of the hydraulic pump is commanded by the operator's software
application, through a dedicated module that does not figurate, and the hydraulic pump 26, is hydraulically connected in a closed circuit, with the hydraulic motor 27, which is mechanically connected with the motor axle 25.
Through the variable command of the pump flux 26, a variation of the speed is obtained even when the revolution of the driving shaft 31, of the gearbox 24, is constant. The gearbox for combined drive subsystem 8, has a revolution sensor 33, that sends impulses to the software application proportionate with the hydraulic motor's 27 revolution, so the software application can calculate precisely the speed of the chassis 1 and therefore, the distance travelled in a set time table. Based on the result of these calculations, corrections will be applied in order to insure the motion's conformity with the command issued.
The chosen constructive solution, allows variable speed commands in a wide spectrum (0.1 - 1 m/s), at very low absolute speed values, impossible to reach using conventional transmission gears trains and without altering the dynamic performances of the chassis 1, when travelling in "transport mode" on public roads.
The subsystem for the automated control of speed and steering 10 described in fig. 9 performs in the first step positioning and orientation data acquisition A0, followed by interpretation of the orientation data Al, steering command generation A2, steering command execution A3, interpretation of the positioning data A4, speed command generation A5, speed command execution A6 and feedback of the performed action RA.
One possible implementing variant of the subsystem for the automated control of speed and steering 10, is realized with some video cameras 34, placed on the vehicles' bumpers in front and back, processing units and specialized software applications, light sources for enhancing the view of the terrain, and steering servo systems.
Acquisition of the data for positioning and orientation A0 has the purpose to receive data from the proximity sensors 21, video camera 34. The received data is divided in order of their relevance into orientation data and speed data.
Through the interpretation of the orientation data Al received, possible deviations from the programmed trajectory are reported. Based on the information about the deviation from the normal trajectory, a steering command A2 is generated, that will operate the steering shaft, through the servo system which will execute the steering command A3.The process receives feedback of the performed action, so, after every command it analyzes the impact over the orientation parameters, the RA information.
Through the interpretation of the positioning data A4 received, the deviations from the correct position are detected. Depending on the recorded position deviations, a speed command will be generated which will be transmitted to the subsystem for the automated control of speed and steering 10 on the mobile scanning unit 1.
The subsystem for acquisition, processing, storage and displaying of scanned image 11, is composed from a series of hardware equipment and software applications, according to the diagram from fig. 8 and it's designed to collect, process, analyze and interpret the radiation signals from the detectors, in order to generate a radiography of the scanned object.
The subsystem 11 is has n groups, each of 16 radiation detectors GDl...GDn, every group being connected to one electronic module, that includes a preamplifier with 16 parallel channels PAl...PAn, which signals are multiplexed in one of the Ml...Mn multiplexers, and then converted analogue-digital in one of the CA/D1...CA/Dn converters, and through one MCl...MCn microcontrollers and one of the CANl...CANn modules, the signals passes through a CAN-BUS to a processing unit UPd running a dedicated software application Sd. Through a CANi interface, the information is transmitted further through a wireless LAN, to a process unit UPa running a software application Sa that displays the radiography on a monitor Mon.
In the frame of the detector boom 2 some electronic modules are mounted, each one commanding groups of 16 detectors each, the number of modules used is determined by the length of the detector boom 2.
The detector boom 2, is connected to a data processing unit connected with the CANi interface. The specialized software application Sd, running on the UPd unit, receives data from the CANi interface and sends them through a radio modem to the mobile control centre 12, where they are interpreted in order to create a radiography of the scanned object. This image is displayed on the monitor Mon, and another application allows the operator to apply different proprietary software filters on the image, in order to enhance some parameters of the image.
The wireless LAN is used to connect the data processing units Upa and Upd.
The exclusion area protection subsystem 13 is an active radiological protection subsystem, which operates directly the source 6, to automatically shut it down in the case that the exclusion area a has been breached. The active sensors of the exclusion area protection subsystem 13, are placed in groups of two in the extremities of a diagonal of the exclusion area a and angled 90 degrees one with the other, they create a virtual barrier two meters high and forty meters long, enough to limit a rectangular surface of maximum 40m x 40m. These sensors are permanently radio connected with the control centre 12, where they send an alarm signal in case of a breach of the infrared barrier. This signal automatically closes the source 6 and activates a text, vocal and graphical message on the graphical interface of the operator's software application, indicating the breached side. The subsystem is designed to work in difficult weather conditions like rain, snow, wind, dust, extreme temperatures, etc.
The subsystem for protection of the exclusion area is deactivated to allow the entry/exit in/out of the exclusion area a, synchronized with the working times of the barriers 15 and 16. When the driver of the inspected vehicle has left the area, the subsystem is reactivated.
The automated traffic management subsystem 14 manages the barriers 15 and 16 and the traffic lights 17 and 18 placed at the entry and exit in the scanning lane in order to control the access of the vehicles that are inspected. This subsystem 14, is controlled automatically by the operator's software application. On the operator's graphical interface live status info are displayed in real time, like barrier up, barrier down, barrier rising, barrier descending, malfunction, red light on, green light on, defective red bulb, defective green bulb. The commands and status are sent throughout some corresponding interfaces and radio modems.
The mobile control centre 12, manage all the components of the mobile inspection system, insuring tiie process automation. For a controlled management and an exact evidence, all commands and feedbacks, status and human interactions are recorded in a "black-box". The communication with the mobile scanning unit 1 is realized through some high speed radio modems as hardware support for data and status communication.
In "scanning mode" the mobile control centre 12, is placed outside of the exclusion area a, close to the entry point. In an implementing variant, the centre 12, can be a caravan with two compartments, an office compartment and a bedroom compartment to provide the operator with optimal working and resting conditions in the case of itinerary travels to perform inspections in different sites. This configuration is preferred considering the possibility that the crew could receive long term and distance missions, and the independence to the accommodation conditions contributes to efficiency and optimization.
The caravan into which the mobile control centre 12 is lodged, is equipped with an electric generator and acclimatisation equipment, that allows it to be electrically independent and to function within the normal limits even if bad weather. In "transport mode" this caravan is towed by the chassis 1 together forming the mobile nonintrusive inspection system.
The removal of the mobile control centre 12 outside of the exclusion area a, as well as the elimination of the need for a driver during scan, eliminates all risks of radiation exposure and makes possible the shortage of operating crew from minimum three per shift necessary to any existing similar systems, to only one person per shift.
A nonintrusive inspection method including that the vehicle that is to be scanned has access in the exclusion area through an automated traffic management subsystem that automatically commands the functioning of the barriers and of the entry/exit semaphores. The vehicle is placed in a marked spot, before its driver left the exclusion area (where there is the irradiation risk), then the protection of the exclusion area is activated, followed by the initiation of the scanning process by remote commands to the mobile scanning unit, when the radiation source is activated and the slow and constant motion movement of the two mobile units is started. The mobile scanning unit is moving slowly along the scanned vehicle, framing it. The movement of the mobile unit is automatically controlled by electronic and informatics modules, connected with the control centre in a local area network, through radio modems, centre from which it receives commands, and towards which it sends in real time status information and specialized data. The stopping of the scan is performed automatically in the following situations, when the detector boom has passed the extremity of the scanned vehicle and the detectors receive the maximum level of radiation, at the end of the programmed scan length, when the protection limiter of the movement is triggered, when the protection of the exclusion area has been breached, when the proximity sensor has been triggered indicating dangerous distance between the detector boom and the scanned vehicle, when obstacles close to the guiding paths have been automatically detected by sensors placed on the mobile units. The stopping of the scanning process can be manually commanded by the operator in any moment. During this stage of the process, the image resulted from scanning the vehicle is displayed on
the operator's monitor and at the end of the stage the protection of the exclusion area is automatically deactivated, and the vehicle may leave the scanning area. The mobile scanning unit moves back to the start position and the scanning cycle may be restarted.

We Claim:
1. A nonintrusive inspection method including that the vehicle that is to be scanned has access in the exclusion area through an automated traffic management subsystem that automatically commands the functioning of the barriers and of the entry/exit semaphores. The vehicle is placed in a marked spot, before its driver left the exclusion area (where there is the irradiation risk), then the protection of the exclusion area is activated, followed by the initiation of the scanning process by remote commands to the mobile scanning unit, when the radiation source is activated and the slow and constant motion movement of the two mobile units is started. The mobile scanning unit is moving slowly along the scanned vehicle, framing it. The movement of the mobile unit is automatically controlled by electronic and informatics modules, connected with the control centre in a local area network, through radio modems, centre from which it receives commands, and towards which it sends in real time status information and specialized data. The stopping of the scan is performed automatically in the following situations, when the detector boom has passed the extremity of the scanned vehicle and the detectors receive the maximum level of radiation, at the end of the programmed scan length, when the protection limiter of the movement is triggered, when the protection of the exclusion area has been breached, when the proximity sensor has been triggered indicating dangerous distance between the detector boom and the scanned vehicle, when obstacles close to the guiding paths have been automatically detected by sensors placed on the mobile units. The stopping of the scanning process can be manually commanded by the operator in any moment. During this stage of the process, the image resulted from scanning the vehicle is displayed on the operator's monitor and at the end of the stage the protection of the exclusion area is automatically deactivated, and the vehicle may leave the scanning area. The mobile scanning unit moves back to the start position and the scanning cycle may be restarted.
2. Nonintrusive inspection system that implements the method described in claim 1, including: a mobile scanning unit installed on an truck chassis (1), containing some detector areas (3 and 4) specific to the radiation type source used (6), a radiation source (6), the unit being autonomous (1) and having subsystems with feedback, for the automated control of speed and steering (10), a boom positioning subsystem (7) and a hydraulic propulsion subsystem (9) to realize the slow motion of the scanning unit. The system includes also a mobile control centre (12), that is placed outside of the scanning area (a) and that remotely manages all processes, including a subsystem for acquisition, processing, storage and displaying of scanned image (11). The system also includes an exclusion area protection subsystem (13), an automated traffic management subsystem (14) and a computer management subsystem (19).
3. Nonintrusive inspection system according to claim 2, where the mobile scanning unit has a detector boom
(2) made out of the upper detector area (3) and the lower detector area (4), the last being mounted
independently, laterally to the right, on the supplementary chassis (28), in an oscillatory fix in a perpendicular
bolt on the longitudinal axle of the chassis and the upper detector area (3), mounted on a steel prop (29) of the
source boom (5) that can pivot in a bearing (30) solidary with the supplementary chassis (28). The two detector areas (3 and 4) have separate folding systems but unitary functionality during scanning procedures.
4. A nonintrusive inspection system according to claim 3, where the detector boom (2) is made out of five segments orientated under different angles, and is made of light alloy assembled in a "T" shape.
5. A nonintrusive control system according to claim 2, where in one implementing variant, the subsystem for the automated control of speed and steering (10) of the mobile scanning unit (1), has an electric motor, to drive the steering column and an electronic automated command and control module.
6. A nonintrusive inspection system according to claim 2, where the hydraulic transmission subsystem (9), that propels the chassis (1) in slow motion has a mechanical gearbox for combined drive subsystem (8), with a revelation sensor (33), a hydraulic pump (26) with electronically controlled variable flow capacity, a hydraulic motor (27) an electronic command module and specialized software application for the automated speed control.
7. A nonintrusive inspection system according to claim 2, where the automated traffic management subsystem (14) in the exclusion area (a) and limitrophe area has some barriers (15 and 16) with some traffic lights (17 and 18) commanded wireless and remotely directly by a specialized software application, and the exclusion area protection subsystem (13) of the exclusion area (a) is made out of some active presence sensors, a control module of the sensors status and an automatic shut down of the radioactive source (6) module in case the exclusion area (a) has been breached.
8. A nonintrusive inspection system according to claim 2, where the subsystem for acquisition, processing,
storage and displaying of scanned image is made out of
some electronic modules that include some preamplifiers (PAl...PAn), some multiplexers (Ml...Mn), some analogue-digital converters (CA/D1...CA/Dn), some microcontrollers (MCl...MCn), a data bus (CAN-BUS), some modules (CANl...CANn), a communication interface (CANi) to a processing unit (UPd) running a dedicated software application (Sd), connected in a wireless LAN to another processing unit (UPa) running another software application (Sa) that displays the radiography of the scanned vehicle on a monitor (Mon).
9. A nonintrusive inspection system according to claim 2, where a boom positioning subsystem (7) monitors
the position reported by the sensors (23) and sends commands to every actuator (22) of each segment of the
source boom (5) and detector boom (2). The position of every segment of the booms in "transport mode",
"scan mode" and intermediary positions is established by the boom positioning subsystem (7) in an automatic manner, following a macro command issued by the operator.
10. Nonintrusive inspection method and system Transducer as claimed in any of the above claims substantially as described in the specification and illustrated in the accompanying drawings.