WO2019117749A1

WO2019117749A1 - System for screening cargo and self-propelled vehicles and method of automatic radioscopic control of moving objects for determining the radiating scanning zone in the screening system

Info

Publication number: WO2019117749A1
Application number: PCT/RU2018/000473
Authority: WO
Inventors: Aleksandr Vladimirovich SIDOROV; Sergej Petrovich NOVIKOV; Vladimir Vital'evich GREBENSHCHIKOV; Andrej Mihajlovich FIALKOVSKIJ; Evgenij Vladimirovich KRIVCHIKOV
Original assignee: Obshhestvo S Ogranichennoj Otvetstvennost'yu "Isb.A" (Ooo "Isb.A")
Priority date: 2017-12-14
Filing date: 2018-07-17
Publication date: 2019-06-20
Also published as: IL275104B1; PH12020550838A1; CN111492417A; CN111492417B; RU2668508C1; IL275104A

Abstract

The invention relates to the field of controlling the self-propelled vehicles and other mobile objects and could be used for screening in order to detect hidden items, substances and materials for reasons of security and reliability of such a control. The technical result of the claimed group of inventions consists in increasing the operation speed and the capacity of the inspected objects, as well as in increasing the security and reliability of the system for screening and controlling, which is achieved by using a laser measuring system (LMS) having the optimally calculated scanning relations of scanning angle and frequency; the implementation of those inventions is confirmed many times in a real-time mode and in real conditions of screening.

Description

SYSTEM FOR SCREENING CARGO AND SELF-PROPELLED VEHICLES AND METHOD OF AUTOMATIC RADIOSCOPIC CONTROL OF MOVING OBJECTS FOR DETERMINING THE RADIATING SCANNING ZONE IN THE SCREENING SYSTEM

Field of the Invention

The claimed group of inventions relates to the field of controlling the self- propelled vehicles and other mobile objects and could be used for screening in order to detect hidden items, substances and materials for reasons of security and reliability of such a control.

Background of the Invention

Known is a large number of methods dedicated for screening the vehicles. For solving that problem, methods based on applying the ionization radiation gained prevalence [1-4]. Among those methods, the methods with the use of the X-ray scanner became the most widespread [2].

Therewith, the general and main disadvantage of the known methods consists in a low capacity, commonly not more than 25-30 units per hour. All those methods use a system comprising a source of high-energy radiation which beam being crossed by the scanned object, a system for detecting the radiation in the beam plane, an electronic tract of analog-to-digital converters, and a shadow image forming electronic system. In some cases, a movement of the inspected object across the beam plane is carried out either using a special device being a part of the system, or the system itself moves relative to a stationary object in the course of scanning. In such systems, a driver leaves the motor vehicle at the moment of inspection, which results in reducing the capacity.

In order for performing a faster control, in some systems a driver does not leave a cabin, and the whole movement is carried out in self-propelled mode, but in this situation, it is needed to provide the driver with a radiation protection, which is ensured by that the motor vehicle comes, prior to the scanning, to the predetermined position where the driver’s cabin is behind the radiation beam plane. After fixing that position, the X-ray radiation and the vehicle movement start, and in this case the driver’s cabin is not scanned. In such systems, is achieved a higher capacity coming up to 60 units per hour. The main disadvantages of those systems consist in a necessity of stopping the vehicle prior to starting the scanning, which reduces substantially the capacity, and in that an inevitable non-uniformity of motion in the course of scanning affects adversely on both the shadow image quality and the overall scanning control.

Known are systems with a great increase of the capacity (up to 200 units per hour) equipped with systems for determining automatically the moment of switching on the X-ray radiation without stopping the self-propelled vehicle [5- 6]. Such systems comprise an automatic system for switching the X-ray radiation source, which automatic system being connected to a series of sensors registering the fact of passing the X-ray radiation zone with the section of object not requiring the scanning.

Among the noted systems, known is the most advanced system [7] being closest for both the claimed system for screening and the claimed method of control. In the known system [7], a device is additionally used that adjusts a pulse frequency of the X-ray radiation source on the basis of object speed data obtained by means of radar, which is important in forming the shadow image, since the inspected objects could move with various speeds when moving self- propelled.

The main disadvantage of the known system consists in a limitedness of its use, because such a system can be used with regard to only specific vehicle types, since the sensors in this system register just the fact of passing the radiation zone with an object of the predetermined fixed line size. Thus, the known system [7] suits only for objects having the same line sizes of the zone not subject to the radiation. The disadvantage of this system, besides the ones indicated above, consists also in insufficiently high quality of the screening control, which is associated with the impossibility for the system to take into account, in forming the shadow image, the non-uniformity of the motion of the object when it passes the X-ray scanning zone, since the system registers the object motion speed only at an approach of the inspected object to the raying zone, so this fact has an adverse effect on the shadow image formation.

Another disadvantage of the known system consists in limitedness of its use, because such a system can be used with regard to only specific vehicle types having a gap between the cabin and container.

Disclosure of the Invention

The claimed group of inventions (system for screening and method of control) is free from the indicated disadvantages.

The technical result of the claimed group of inventions consists in increasing the operation speed and the capacity of the inspected objects, as well as in increasing the security and reliability of the system for screening and controlling.

The indicated technical result is unique for the claimed group of inventions (i.e., for the system for screening and for the method of control).

The indicated technical result is achieved by that in a system for screening cargo and self-propelled vehicles, the system comprising a X-ray radiation source with a collimator, an X-ray radiation source control device, a portal having vertical and horizontal consoles and radiation detectors mounted thereon, the vertical and horizontal detector consoles being joined to one another and disposed at the portal side opposite to the X-ray radiation source, an analog-to- digital converters (ADC) electronic tract, a shadow image forming electronic device connected to the detectors via the ACD tract, in accordance with the claimed invention, the X-ray radiation source control device is performed with use of laser scanners, one of which being disposed from the raying zone at a distance not less than a length of a size, maximally permissible by the portal, of the inspected object in the direction of movement thereof, and having the beam sweep in the horizontal plane, another laser scanner being disposed in close vicinity to the raying zone and having the beam sweep in the vertical plane, the laser scanners being connected to a controller for locating the inspected object relative to the raying zone, for determining a section of the inspected object not subject to the raying, and for switching on/off the radiation source, the controller being connected to the shadow image forming electronic device.

Moreover, the indicated technical result is achieved by that the X-ray radiation source control device being performed with use of not less than two laser scanners.

Besides that, the indicated technical result is achieved by that the X-ray radiation source control device comprises additionally a laser scanner having the beam sweep in the horizontal plane and mounted at another height relative to the laser scanner having the beam sweep in the vertical plane.

Moreover, the indicated technical result is achieved by that the X-ray radiation source control device comprising not less than two laser scanners having the beam sweep in the horizontal plane and disposed at different heights relatiMy to one another.

In addition to that, the indicated technical result is achieved by that a laser measuring system (LMS) having a scan angle from 0 to 180 deg. with a scan frequency 100 Hz and an angle measuring resolution 1 deg. being used as the laser scanner.

Besides that, the indicated technical result is achieved by that the LMS of the firm SICK being used as the laser scanner.

Moreover, the indicated technical result is achieved by that the shadow image forming electronic device being connected to the laser scanner controller.

The indicated technical result is also achieved by the claimed method of automatic radioscopic control of moving objects and X-ray scanning zone, the method including steps of: switching on a radiation source when an inspected object enters the raying zone and its section not subject to the raying passes that zone; and switching off the radiation source when the inspected object passes entirely the raying zone, wherein, in accordance with method implemented in the claimed system, determining the fact when the inspected object enters the raying zone by a laser scanning, in the horizontal plane, of space region at the place where the self-propelled inspected object enters the raying zone; determining the object section not subject to the raying in accordance with the presence of a gap between a driver’s cabin and a container of the inspected object by means of the laser scanning in the vertical plane in front of the raying zone; and registering, in accordance with the obtained results of the laser scanning input into a controller, the fact when the inspected object enters the raying zone, as well as the facts when the section not subject to the raying passes through and when the inspected object passes the raying zone entirely.

Moreover, the indicated technical result is achieved by that the gap between a driver’s cabin and a container of the inspected object is determined in accordance with a sectional area of the inspected object as obtained from the results of the laser scanning in the vertical plane.

Besides that, the indicated technical result is achieved by that the mean height of the upper part of the inspected object is analyzed using the laser scanning, and, in the case of uniformity of that height at a length of the inspected object for more than two meters, the beginning of the container with a cargo passing the raying zone is determined.

Moreover, the indicated technical result is achieved by that the laser scanner is situated in the vertical plane at the same distance in front of the raying zone that the length for analyzing the uniformity of the mean height of the inspected object, i.e., two meters.

The indicated technical result is also achieved by the claimed method for forming a shadow image of the inspected object, the method comprising the step of forming an image numerical matrix according to a data of radiation detection system, which system being used for visual acquisition of the shadow image, and in which system, in accordance with the method implemented at the claimed system, are comprised additional steps of: using, when forming the image numerical matrix, the data on a location of the inspected object obtained from the laser scanners; and on the basis of that data, computing a correspondence of the relative position of the inspected object and responses of the detectors; upon which, re-computing the data obtained from the detectors into a sequence of the responses corresponding to an even movement of the inspected object amongst those detectors.

Besides that, the indicated technical result is achieved by that the step of computing the correspondence of the relative position of the inspected object and the responses of the detectors, and the step of re-computing the data obtained from the detectors into the sequence of the responses corresponding to the even movement of the inspected object amongst those detectors are performed by interpolation using values of frequencies of the laser scanning and X-ray scanning.

Description of the Claimed Invention An essence of the claimed invention is illustrated at Figs. 1 to 4, showing the system of radioscopic control of moving objects. Herewith, the mutual arrangement of the main system elements and the position of the inspected object when coming to the X-ray scanning zone is shown in Fig. 1 (Fig. la is the plan view, Fig. lb is the side view).

Fig. 1 shows a portal (4) having an X-ray radiation source (6) and a collimator (7) that are situated at one side of a route (8), a system of radiation detectors (5) situated opposite the radiation source (6) at another side of the route. In Figs la and lb, a first laser scanner (1) for scanning a beam in the horizontal plane (10) is mounted at one side of the route (8) beyond the portal (4) and at a distance therefrom exceeding the maximum allowable size of the inspected object (3) in the movement direction, which size being used for determining a speed of the inspected object (3); a second laser scanner (2) for scanning a beam in the vertical plane (9) across the route (8) is mounted above the route at a distance not less than 2 meters from the raying zone and serves for determining a section of the inspected object (3) subject to the raying and inspection of the cargo module.

Fig 2a shows that the scan of the laser scanner (2) having the beam sweep in the vertical plane (9) shown in Fig. lb consists of a set of vectors S₀, S_ls ... , Siso in the vertical plane within a range from 0 to 180 degrees in increments of 1 degree. The vector is a distance from a scanner to a laser beam reflection point in meters and a direction in the scanning plane in degrees. A vector Sj having a minimum value of the vector modulus measured in the absence of the inspected object is taken as the distance H, used in calculations, between the laser scanner (2) having the beam sweep in the vertical plane and the route (8). A data array obtained using the laser scanner (2) having the beam sweep in the vertical plane with values of the modulus and propagation directions of all vectors at one measurement cycle, which data array lasting 10 milliseconds at a scanning frequency 100 Hz, is transmitted by means of telegrams (the data array dimension of one scan for the LMS of the“SICK” firm in the scanning angle 180 degrees is equal to 720 bytes) via the interface RS-422 or Ethernet by the laser scanner to a controller (11) (Fig. 3) where those data are processed and analyzed. The laser scanner (1) having the beam sweep in the horizontal plane functions on the same principle and with the same scanning frequency.

Figs. 2a and 2b show how to determine a value of the medium distance D_m from the laser scanner (2) having the beam sweep in the vertical plane to the profile of the vehicle top part, which value is used in further calculations. The controller performs an analysis of data coming from the scanner (2) having the beam sweep in the vertical plane in such a manner that vectors having values of the vector modulus more than the value of the distance H are rejected. For example, vectors from S₀ to S_M and from Sj_+n+i to S_l80 will be rejected, because their values are more than the value of the distance H. And vectors from S to S _+n have values less than the value of the distance H. These vectors determine a profile of the vehicle upper part. Then, a distance for each profile point“i” is determined along a perpendicular to the laser scanner having the beam sweep in the vertical plane in accordance with an equation:

Dj = Si * cos (Q_j), where

D is a distance from every profile point“i” to the laser scanner having the beam sweep in the vertical plane,

Si is a value of the scan vector for this profile point, the value measured by the laser scanner having the beam sweep in the vertical plane,

Qi is an angle of the scan vector of that profile point.

The medium distance D_m from the profile of the vehicle upper part to the laser scanner having the beam sweep in the vertical plane is determined as the arithmetic mean value of the distances from D_j to Dj_+n.

A value of the mean distance from the vehicle forepart (“nose”) profile to the laser scanner (1) having the beam sweep in the horizontal plane (Fig. lb) for using in calculations of the vehicle speed is determined in the same way. Herewith, the vehicle speed is determined by the scanner having the beam sweep in the horizontal plane based on the value of vehicle movement and the time between the previous and subsequent scans of the scanner having the beam sweep in the horizontal plane in accordance with the equation:

V = L_g / T_g, where

V is the vehicle speed,

L_g is the distance of vehicle movement in a time between the previous and subsequent scans of the laser scanner having the beam sweep in the horizontal plane, which distance is equal to a difference of the mean distances from the inspected vehicle forepart profile to the laser scanner having the beam sweep in the horizontal plane at the previous and subsequent scans of that scanner,

T_g is the time between the previous and subsequent scans of the laser scanner having the beam sweep in the horizontal plane, and this time is equal to a value reciprocal of the scanning frequency of that scanner.

In the claimed invention, the principle for detecting the beginning of container in front of the X-ray radiation source zone (Fig. lb) is based on that the height of the upper part of container of the inspected object (3) is a uniform amount when the vehicle moves in the scanning plane (Fig. 2b) of the laser scanner (2) having the beam sweep in the vertical plane. Therefore, the uniformity of the mean height of the upper part profile of the vehicle during more than two meters is a criterion for determining the beginning of the container and the moment of switching on the X-ray radiation source (6) shown in Fig. la. This criterion is selected on the basis of analyzing the maximum length of cabins of all known vehicles, for which the present system for screening cargo and self-propelled vehicles is designed. The laser scanner (2) having the beam sweep in the vertical plane is placed at the same distance, i.e., at the distance not less than two meters from the portal (4) having consoles in front of the X-ray radiation source in the direction of the inspected object movement, Fig. la, in order for the container beginning comes just in front of the X-ray radiation source (6) at the moment of switching on thereof.

A value of the mean height H_m of the vehicle above the route (8) is controlled for determining a flat upper part of the vehicle at each scanning (Fig. 2a and 2b), which mean height is determined according to a difference:

H_m = H - D_m, where

H is a distance between the laser scanner (2) having the beam sweep in the vertical plane and the route (8),

D_m is a mean distance from the upper part profile of the vehicle to the laser scanner (2) having the beam sweep in the vertical plane. The flat upper part of the vehicle will be fixed from a moment when the mean height H_m in the current scan becomes larger than zero, which fact is interpreted as appearance of the vehicle in the scanning plane of the laser scanner (2) having the beam sweep in the vertical plane. If the mean height H_m in the next scan is not equal to the mean height H_m of the previous scan, then the controller remains in the monitored mode and does not generate control signals. But when the mean height H_m in the next scan is equal to the mean height H_m of the previous scan, the distance travelled by the vehicle between the previous and next scans of the laser scanner (2) having the beam sweep in the vertical plane is determined according to the next equation:

L = V * T_v, where

L is a distance at which the vehicle has travelled during a time between the previous and next scans of the laser scanner (2) having the beam sweep in the vertical plane,

V is a vehicle speed,

T_v is a time between the previous and next scans of the laser scanner (2) having the beam sweep in the vertical plane, and this time is equal to a reciprocal scanning frequency of that scanner. Then the value of the distance L is summed in the adder of the controller (11), where the sum is initially reset to the zero. If the condition of equality of the mean height H_m is fulfilled in the next scan, then the newly calculated distance L is also summed in the adder. If a scan occurs where the mean height H_m is not equal to the mean height H_m of the previous scan, then the sum in the adder is reset to the zero.

If the sum in the adder exceeds a value of two meters, the criterion for screening the inspected vehicle will be considered as fulfilled, and the controller (11) in Fig. 3 sends a signal for switching on the X-ray radiation source just at the moment when the beginning of the container enters into the raying zone, and after that, the controller (11) continues to process data from the laser scanner (2) in order to determine a moment of full passage of the inspected vehicle (3) through the raying zone. When the value of the height H_m becomes zero, the controller sends a command for switching off the X-ray radiation source (6) after a small delay needed for the end of the container to leave the raying zone.

Further, the system waits for appearing a next vehicle (Fig. 2a) in the scanning plane of the laser scanner (2) having the beam sweep in the vertical plane.

Fig. 3 shows all elements of the system, where the detecting system (5) is connected with the electronic analog-to-digital converter tract (12) and the electronic shadow image forming device (13); the laser scanner (1) having the beam sweep in the horizontal plane and the laser scanner (2) having the beam sweep in the vertical plane, as well as the X-ray radiation source (6) with a collimator (7) are connected to the controller (11).

It is possible to use the laser measuring system LMS of the firm“SICK” as the first (1) and second (2) laser scanners. That system is characterized by a high scanning speed a high accuracy in determining the object distance.

The operating principle of the LMS made by“SICK” is based on a time for measuring a propagation of beam that passes through a rotating mirror and, after reflecting from an object, comes back into a photo-receiver of the scanner. The object distance is determined by measuring the time of the beam propagation in a space. By virtue of the rotating mirror, the measurement is carried out in the same plane.

Fig. 4 shows examples of measuring a moment of switching on the X-ray radiation source. In Fig. 4a, the forepart of the driver’s cabin passes the scanning plane of the laser scanner (2) having the beam sweep in the vertical plane. In this case, the mean height H_m varies (increases) permanently, and the X-ray radiation source (6) is not switched on.

In Fig. 4b, the top flat part of the driver’s cabin passes the scanning plane of the laser scanner (2) having the beam sweep in the vertical plane. In this case, the mean height H_m is constant, but the length of this part of the cabin is less than two meters, and the X-ray radiation source is not switched on.

In Fig. 4c, the top flat part of the container passes the scanning plane of the laser scanner (2) having the beam sweep in the vertical plane. In this case, the mean height H_m of the container remains constant, and as soon as the container having the length of two meters passes under the laser scanner (2), the X-ray radiation source (6) will be switched on.

The claimed system for screening cargo and self-propelled vehicles allows for taking into account a non-uniformity of the inspected object motion in the course of X-ray scanning. This is achieved by using the data on a location of the inspected object (3) relative to the raying plane in the process of scanning that object, when forming a shadow image (Figs. 4a to 4c). During the X-ray scanning (Fig. 3) that starts from the moment of switching on the X-ray radiation source (6), the shadow image forming electronic device (13) receives and buffers data from the detecting system (5) via the ADC electronic tract (12) and from the controller (11). Upon termination of the X-ray scanning, the shadow image forming electronic device (13) processes the received data and forms the shadow image in the form of numerical matrix.

The data processing is based on the fact that the data entering the shadow image forming electronic device (13) has a load-time binding determined by frequencies of the X-ray scanning and laser scanning. Thus, the X-ray scanning data (the array sequence of the digitized responses from detectors) are time divided one from another by identical time interval determined by the given X- ray scanning frequency. This allows, for each detector, to develop a dependence of the response thereof from the time starting on the moment of the X-ray scanning beginning.

Similarly, it is possible to develop the time dependence (Fig. 4a to 4c) of the position of the inspected object (3) on account of the X-ray scanning frequency, on which basis is built an inverse dependence of the time from the position of the inspected object (3) starting from the beginning moment of the X-ray scanning. Herewith, procedures of data smoothing and interpolation can be used. The results of such processing are converted into a data array where a time coordinate corresponds to each movement of the inspected object (3) at a given fixed distance. Further, using those data and the interpolation techniques, the detector response data are converted. For each detector, a new data array is built, where the response corresponds to a given fixed movement of the object. A converted data set of the detector responses forms a numerical matrix of the shadow image. The described algorithm is realized by the shadow image forming electronic device (13) (Fig. 3).

The technical-and-economic efficiency of the claimed group of inventions consists in increasing the operation speed and the capacity of the system and in the possibility for scanning vehicle without a gap between the cabin and container, as well as in increasing the security, reliability and accuracy of the inspected vehicle screening due to the system structural design and the screening method realized on the basis thereof, that method envisaging the determination of the zone not subject to the raying, as well as the new method for forming the numerical matrix of the shadow image and for forming the shadow image permitting to take into account the non-uniformity of the object motion in the course of the radiation scanning.

Reference list

1. Hussein E., 1992, Gozani T., 1997, AnJ. Etc, 2003.

2. RU Patent 2284511.

3. RU Patent 2297623.

4. RU Patent 2239821.

5. US Patent 7688945 (RU Patent 2390007).

6. US Patent 7352844.

7. US Patent 7492861 (RU Patent 2340006) - prototype.

Claims

1. A system for screening cargo and self-propelled vehicles, the system comprising: an X-ray radiation source with high penetrating power having a collimator, an X-ray radiation source control device, a portal having consoles and radiation detectors mounted thereon and disposed at the portal side opposite to the X-ray radiation source, an electronic tract for forming and collecting signals from the detectors, and a shadow image forming device connected to said tract, the X-ray radiation source control device is performed with the use of laser scanners, one of which being disposed from the radiation zone at a distance not less than a length of a size, maximally permissible by the portal, of the inspected object in the direction of movement thereof and having the beam sweep in the horizontal plane, another laser scanner being disposed in close vicinity to the raying zone and having the beam sweep in the vertical plane, the laser scanners being connected to a controller of inspected object location relative to the raying zone for determining a section of the inspected object not subject to the raying, wherein the laser scanner having the beam sweep in the vertical plane is disposed at a distance from the portal having consoles not less than two meters prior to the X-ray radiation source in the direction of the inspected object movement.

2. A method of automatic radioscopic control of moving objects and determination of the X-ray scanning zone, the method including steps of: switching on a X-ray radiation source when an inspected object enters a raying zone and a section thereof not subject to the raying passes said zone; and switching off the X-ray radiation source when the inspected object passes the raying zone entirely; determining the fact when the inspected object enters the raying zone by a laser scanning, in the horizontal plane, of the space region at the place where the self-propelled inspected object enters the raying zone; registering, in accordance with obtained results of the laser scanning input into a controller, the fact when the inspected object enters the raying zone, as well as the facts when the section not subject to the raying passes through and when the inspected object passes the raying zone entirely; wherein determining, in the process of movement of the inspected object, a vehicle upper part profile in the scanning plane of the laser scanner having the beam sweep in the vertical plane perpendicular to a route which width corresponds to a width of said portal; said profile is determined in the form of a set of only those points which vector values are less than a distance H between the laser scanner having the beam sweep in the vertical plane and the route; determining, for each profile point“i”, a distance to the laser scanner having the beam sweep in the vertical plane in accordance with an equation:

D_j = S; * cos (Qi), where

D_j is a distance from every profile point“i” to the laser scanner having the beam sweep in the vertical plane,

S; is a value of the scan vector for this profile point, said value measured by the laser scanner having the beam sweep in the vertical plane,

Qi is an angle of the scan vector of that profile point;

determining, according to the obtained values D , the medium distance D_m from the vehicle upper part profile to the laser scanner having the beam sweep in the vertical plane for each profile point; upon which, determining a difference of the distance H, known for the used portal, between the laser scanner having the beam sweep in the vertical plane and the route, and the mean distance, and accepting said difference as a mean height H_m of the inspected vehicle; then determining a distance travelled by the vehicle between the previous and next scans of the laser scanner having the beam sweep in the vertical plane according to the next equation:

L = V * Ty, where

V is a vehicle speed, L is a distance at which the vehicle has travelled during a time between the previous and next scans of the laser scanner having the beam sweep in the vertical plane,

T_v is a time between the previous and next scans of the laser scanner having the beam sweep in the vertical plane, and said time is equal to a reciprocal scanning frequency of that scanner;

herewith, determining, by the laser scanner having the beam sweep in the horizontal plane, the vehicle speed in accordance with the value of the vehicle movement and the time between the previous and next scans of the laser scanner having the beam sweep in the horizontal plane in accordance with the equation:

V = L_g / T_g, where

V is the vehicle speed,

L_g is the distance of vehicle movement at the time between the previous and subsequent scans of the laser scanner having the beam sweep in the horizontal plane, which distance is calculated as a difference of mean distances from the inspected vehicle forepart profile to the laser scanner having the beam sweep in the horizontal plane at the previous and subsequent scans of that scanner,

T_g is the time between the previous and subsequent scans of the laser scanner having the beam sweep in the horizontal plane, and said time is equal to a value reciprocal of the scanning frequency of that scanner;

upon which, in the case of equal value of the vehicle mean height, determining a sum L of distances between the previous and subsequent scans of the laser scanner having the beam sweep in the vertical plane; and in the case when the value of said sum exceeding two meters, forming a signal for switching on the X-ray radiation source; herewith, controlling the mean height H_m of the inspected vehicle, and when the H_m value is equal to zero, forming a signal for switching off the X-ray radiation source.