Method for detecting an object using a detector using radiation energy and detector for carrying out the method

Abstract

To provide a detection method using radiation energy and a related detector capable of more surely detecting an object held by an individual even when the object is located in an area where probing by the radiation energy is more difficult.SOLUTION: The subject is placed facing one of the side panels 2 with his arms along his body or spread out in the median plane P, the subject is placed perpendicular to the two side panels 2, and he places his arms away from his body so as to spread them out on his front or lateral side at shoulder height.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to the field of detectors designed to detect unauthorized objects or substances in secured access areas.

[0002] The present invention relates to the field of body scanners, particularly those designed to screen passengers before boarding at airports or individuals entering public venues such as stadiums and performance venues, to detect prohibited objects concealed under clothing, and such devices can, among other things, avoid systematic pat-downs. [Background technology]

[0003] There is a need to ensure that attempts to bring prohibited products, especially weapons and explosives, into and out of sensitive locations are controlled. This issue covers a very wide range of situations, including attempts to bring prohibited products into secured areas such as airports, shops, schools, train stations, public and private institutions, as well as attempts to take products outside established boundaries, such as theft within businesses and secured areas.

[0004] There are many different types of metal object detectors. Continuous-wave walk-through portals, in particular, have been proposed for metal object detection for many years. These walk-through portals use waves of constant amplitude and frequency, typically in the 70 Hz to 50 kHz frequency range. They comprise at least one transmitter coil and at least one receiver coil. The transmitter coil is supplied with an alternating current. The receiver coil is designed to detect disturbances in the magnetic field generated by the transmitter coil due to the presence of a metal object, such as attenuation of the magnetic field amplitude or a change in the signal phase due to eddy currents generated in the metal object.

[0005] It has also been proposed to use body scanners. The oldest body scanners are X-ray body scanners. Newer body scanners use so-called millimeter wave (or microwave) technology. An example of a body scanner is described in EP 2 202 700 A1.

[0006] In recent years, body scanners have been developed to detect weapons, explosives, and other items concealed under the clothing of individuals entering secure areas. These scanners use technology that detects modulated radiant energy reflected or emitted from the subject's body. These radiant energies include X-rays, microwaves, millimeter waves, infrared, terahertz waves, and ultrasound.

[0007] Regardless of the type of radiation or imaging format, all body scanners create an electronic image that can be seen through a person's clothing. This image is displayed on a screen and viewed by an operator to determine whether the person is carrying an object. To this end, an operator trained in object detection must be able to determine whether an object identified by the body scanner is a human anatomy, a permit such as a lighter, handkerchief, or part, or an object such as a weapon or explosive. Alternatively, to respect the privacy of the person being scanned, the system may include software containing coded instructions that automatically analyze the image, determine whether an anomaly is present, and display it on an avatar representing the individual.

[0008] Recently, it has become clear that individuals attempting to illicitly smuggle prohibited items, especially weapons, into secure areas are highly imaginative in concealing them, for example by distributing them across various parts of their body. Therefore, when objects are concealed in a way that makes it difficult for radiated energy to reach them, body scanner inspections become increasingly complex and time-consuming. In particular, to ensure reliable detection by body scanners, the more closely the front and back surfaces of the subject are scanned, the less scanning is done of the subject's sides. In fact, the intensity of the energy reflected from these surfaces is very low, and due to their position relative to the transducers, most of the waves are reflected outside the plane where the transmitting and receiving transducers are located. Therefore, these reflected waves cannot contribute to the generation of an electronic image. This risk becomes even greater the greater the surface area of ​​the subject's sides (i.e., the distance between the front and back surfaces).

[0009] To mitigate this risk, it has been proposed to increase the sensitivity of body scanners. However, increasing the sensitivity increases the number of false alarms and the number of physical checks by security personnel. This not only significantly delays the time required for an individual's inspection, reducing the efficiency of the inspection, but is also often perceived as a nuisance by the person being inspected.

[0010] It has also been proposed to add transducers specifically designed for scanning hidden areas to improve radiation exposure in these areas. However, this would significantly increase the number of system resources and costs compared to the number of resources required to probe the front and back of the subject's body, which are directly exposed to radiation from the antenna. Furthermore, an increase in the number of transducers necessarily means an increase in the time required to process the signals from these transducers in order to obtain significant responses from the subject's lateral areas. This processing is highly inefficient in terms of resources and scanning time compared to imaging the body surfaces parallel to the transducers (typically the front and back), which respond with higher intensity in the same direction as the transmitting and receiving transducers.

[0011] Another proposal is to use multiple detectors in series, such as a metal detector and a body scanner. However, while existing metal detectors are the most efficient means of detecting the presence or absence of metal objects, regardless of their location relative to the subject, they cannot locate non-metallic objects on the subject. If a non-metallic object is hidden in a location that is difficult for the body scanner to reach, there is always a risk that the object will not be identified.

[0012] Finally, it has been proposed to fabricate a walk-through portal with a rotatable detector mounted on a cylindrical wall. Rotation of the detector allows for circumferential scanning of the subject to obtain a complete image. However, the cylindrical shape creates problems: it has a large footprint, is easily imprinted on the subject, and requires a long time to process the scanned and recorded information. Furthermore, the system requires two openings for the subject's entry and exit, which limits complete circumferential scanning of the subject. Commercially available systems have a maximum scanning angle of 240 degrees, and do not scan beyond 60 degrees, which corresponds to the entrance, or 60 degrees, which corresponds to the exit. Summary of the Invention

[0013] The object of the present invention is to propose a detection method and a detector using radiant energy for detecting targets that overcome the aforementioned drawbacks.

[0014] In particular, it is an object of the present invention to provide a radiant energy detection method and associated detector that can more reliably detect objects carried by individuals, even when these objects are located in areas that are more difficult to detect using radiant energy, and thereby can be fast, efficient, reduce the rate of false alarms, and reduce the resources required to implement it.

[0015] To this end, according to a first aspect of the present invention, there is provided a method for detecting an object using a detector that utilizes radiant energy, the detector comprising two opposing side panels that are fixed together and together define a passageway; Step S1: placing the subject at a first position in a passage between side panels of the detector; a step S2 of acquiring a first signal representing radiant energy when the test subject is in a first position; Step S3 of placing the test subject at a second position different from the first position in the passage between the side panels of the detector; Step S4 of obtaining a second signal representative of the radiated energy when the test subject is in a second position; and generating an electronic image S5 based on the first signal and the second signal to determine whether the subject is carrying the object.

[0016] Certain preferred but non-limiting features of the detection method according to the first aspect, individually or in combination, are the following:

[0017] Between the first and second positions, the test subject rotates through an angle different from 180°.

[0018] Between the first and second positions, the subject makes a quarter turn.

[0019] The method further includes, before step S3, step S6 of sending instructions to the test subject to move from the first position to the second position.

[0020] In step S6, the indication is visible and / or audible.

[0021] In step S1, the subject is positioned facing one of the side panels, and in step S3, the subject is positioned perpendicular to the side panel.

[0022] In step S1 and / or step S3, the subject places their arms away from their body.

[0023] The method further includes processing the first signal and the second signal by a central device to detect an object held by the test subject.

[0024] Before step S4, a first signal is sent to the central device.

[0025] During all or part of steps S3 and S4, the first signal is processed.

[0026] The central device combines the first signal and the second signal to generate a single electronic image of the subject.

[0027] According to a second aspect of the present invention, there is provided a detector utilizing radiant energy, comprising: two opposing side panels secured to one another and together defining a passageway; a radiant energy transducer, such as a microwave antenna, housed in at least one of the side panels; a central unit configured to perform the detection method of the first aspect.

[0028] Particular preferred but non-limiting features of the detector according to the second aspect are, individually or in combination:

[0029] The detector further comprises a visible and / or audible indicator, and the central device is configured to send instructions to the visible and / or audible indicator to move the test subject from the first position to the second position.

[0030] The visual indicators consist of at least one of the following means: one or more lights mounted on a platform extending between the side panels; a projector configured to project one or more images onto the platform and / or at least one of the side panels; and a loudspeaker configured to emit an audible message to attract the attention of the person being tested.

[0031] Each of the side panels has an inner surface facing the opposite side panel, and the inner surface is curved.

[0032] Other characteristics, objects and advantages of the present invention will become apparent from the following description, which is purely illustrative and non-limiting, read in conjunction with the accompanying drawings, in which: [Brief explanation of the drawings]

[0033] [Figure 1]1 is a schematic diagram of a detector according to a first embodiment of the invention, in which the subject under examination is positioned in a first position and a surface of the subject under examination that is likely to be probed by a radiation transducer is shown schematically; [Figure 2] 2 is a schematic view of the detector of FIG. 1 when the subject is positioned in a second position, which diagrammatically shows the surface of the subject likely to be probed by the radiation transducer; [Figure 3] 3 is a flow chart illustrating steps of a detection method according to one embodiment of the present invention. [Figure 4] 3 is a flow chart illustrating steps of a detection method according to one embodiment of the present invention. [Figure 5] 1 is a flow chart illustrating steps of a detection method according to an embodiment of the present invention, showing an example of a detector according to the present invention and the position of a person being examined in cross section;

[0034] In all figures, similar elements are given the same reference numbers. DETAILED DESCRIPTION OF THE INVENTION

[0035] The radiant energy object detector 1 according to the present invention comprises two fixed, opposing side panels 2 that together define a passageway through which an inspected person passes. The side panels 2 are substantially symmetrical with respect to a central plane P (an imaginary plane of symmetry). In one embodiment, the side panels 2 are connected together at their upper ends by a ceiling and / or at their lower ends by a platform 4. Alternatively, the side panels 2 may be separate and independent, not connected via the ceiling or platform 4.

[0036] Each side panel 2 has an inner surface 3 facing the passageway. More specifically, the inner surface 3 of a first side panel 2 faces the inner surface 3 of a second side panel 2 so as to laterally define the passageway.

[0037] The detector 1 further comprises an array of radiant energy transmitting / receiving transducers 5 and a central unit 6 configured to receive signals representative of the radiant energy reflected and measured by the transducers 5 and to derive an electronic image therefrom.

[0038] A transducer 5 is arranged on the inner surface 3 of at least one of the side panels 2, preferably each side panel 2. Each transducer may successively form a transmitter configured to generate radiant energy and a receiver configured to receive radiant energy.

[0039] In one embodiment, each transducer comprises an antenna 5 configured to generate radiant energy such as millimeter waves (also called microwaves), x-rays, or terahertz waves.

[0040] The present invention will be described in more detail below with reference to a non-limiting example in which the transducer 5 comprises a microwave antenna 5, i.e., an antenna 5 configured to generate waves with wavelengths between 3 mm and 20 mm (i.e., a frequency range of approximately 15 GHz and 100 GHz). Microwaves are suitable for detecting metallic and non-metallic objects, such as ceramic objects. Furthermore, air and other materials, such as those used in clothing, are transparent to this radiation. Therefore, microwaves can be used to detect objects hidden under clothing. To detect objects, the microwave antenna 5 (transmitter) generates microwave pulses or frequency sweeps. Energy reflected from each part of the subject is measured by the microwave antenna 5 (receiver), and signals representing this reflected energy are transmitted to a central device 6, which analyzes the signals and generates an electronic image of the subject, essentially showing the clothing being transmitted through the detector. If desired, the detector 1 may further include a network interface configured to receive and transmit signals representing the reflected energy to the central device 6.

[0041] The central unit 6 may in particular consist of a computer such as a processor, microprocessor, microcontroller or the like configured to execute code instructions for processing the signals representative of the radiant energy reflected and measured by the transducer 5 and for deriving an electronic image.

[0042] Optionally, the detector 1 further comprises a presence detection means, for example a light barrier arranged at the entrance of the detector 1. If necessary, the detector 1 further comprises a traffic light arranged at the entrance of the detector 1 and synchronized with the presence detection means to indicate whether the test subject may enter the detector 1. The traffic light may, for example, be of the green light / red light type (see FIG. 5).

[0043] To improve object detection, the following steps are followed to perform a personal inspection. S1: The subject is placed at a first position in the passage between the side panels of the detector. S2: Obtain a first signal representing radiant energy when the test subject is in a first position. S3: The subject is placed in a second position different from the first position in the passage between the side panels of the detector. S4: Obtain a second signal representing the radiated energy when the test subject is in a second position. S5: Based on the first signal and the second signal, an electronic image is generated to detect the object held by the subject.

[0044] More specifically, during step S1, the subject is placed in a first position between the side panels 2 of the detector 1.

[0045] This first position may be conventional and corresponds, for example, to a position in which the person being tested is positioned facing one of the side panels 2, generally in a central plane P, with the legs spaced apart and substantially parallel to this central plane P. The arms may be along the body or may be spread apart in the central plane P. The first position is shown in FIG.

[0046] Thus, in this first position, the antenna 5 can generate microwaves that scan the front (back) of the person being examined, and the first electronic image obtained represents the front (back) of the person being examined.

[0047] In step S2, all or part of the microwave antenna 5 housed in the first side panel 2 and / or the second side panel 2 generates and radiates a pulse or train of microwaves in the direction of the passageway. These microwaves interact with opposing surfaces, i.e., the body of the person being examined, their clothing, and any objects the person may be hiding under their clothing, as well as the inner surface 3 of the opposing side panel 2. This interaction causes the microwave energy to be modulated and reflected back to the antenna 5, which acts as a receiver.

[0048] The energy reflected from each part of the subject is measured by a receiver, antenna 5. Each antenna 5 then transmits a first signal representing this reflected energy to a central device 6 (steps 2.1 and S4.1), which processes this signal to generate an electronic image of the subject (step S5). If necessary, this transmission can be via a network interface.

[0049] During step S3, the test subject is placed in a second position different from the first position. In one embodiment, the test subject rotates himself between the first and second positions so that different sides of his body face the side panels 2. Thus, in particular when two side panels 2 house microwave antennas 5 (the antenna 5 of one panel being capable of generating an electronic image of the subject's front side and the antenna 5 of the other panel being capable of generating an electronic image of the subject's back side), the angle of rotation between the first and second positions is different from 180°.

[0050] In one embodiment, the test subject performs a quarter turn to switch from the first position to the second position so that the angle between the first position and the second position is approximately 90° (within 20°) (modulo 180°). Advantageously, if the second position is substantially perpendicular to the first position, the side of the test subject that was perpendicular to the inner surface 3 of the side panel 2 in acquisition step S2 will face the side panel 2 in acquisition step S4. This improves the ability of the microwave antenna 5 to probe the side of the test subject, and the intensity of the energy reflected from these side surfaces in step S4 increases compared to the energy reflected from the same areas in step S2. This can reduce the number of resources (microwave antennas 5) required to improve detection of these areas, and shorten the processing time for the first and second signals.

[0051] To improve lateral exploration in the second position, the subject may raise their arms in front of or to the side of them, approximately parallel to the ground and at shoulder height. Thus, in this second position, the antenna 5 can scan the entire right side (left side) of the subject with their arms raised, and the resulting second electronic image represents the right side (left side) of the subject.

[0052] Step S4 is essentially the same as step S2, except for the location of the person under test (which is placed at a second location instead of the first location). Thus, at the end of this step, each antenna 5 transmits a second signal to the central unit 6, representing the energy reflected by the person under test at the second location, for processing by the central unit 6 and generation of an electronic image. If necessary, this transmission can be via a network interface.

[0053] Step S4 can be initiated automatically by the central device 6. For example, the detector 1 may comprise a detection means (photoelectric barrier, presence detection means, etc.) configured to determine whether the person being inspected is in the second position and arranged on the ground or on the side panel 2. Alternatively, step S4 can be initiated manually by a security officer, for example by pressing an acquisition button, when the person being inspected is correctly positioned in the second position.

[0054] In one embodiment, the method further includes a step S6 in which the central device 6 sends instructions to one or more indicators 7 configured to guide the test subject to place them at the first position and / or the second position. These indicators may be, for example, visible and / or audible. This enables the central device 6 to coordinate the placing steps S1 and S3 and the acquiring steps S2 and S4.

[0055] In a first embodiment, the indicator 7 consists of one or more lights arranged on the platform 4 of the detector 1 and configured to receive instructions to turn the central device 6 on / off.

[0056] For example, as shown in FIGS. 1 and 2 , the detector 1 may include a series of light-emitting diodes (LEDs) 7 arranged to form two sets of shoe marks: a first set 8 corresponding to the position of the test subject's feet at a first position within the central plane P (e.g., facing one of the side panels 2), and a second set 9 corresponding to the position of the test subject's feet at a second position (e.g., perpendicular to the side panel 2 and the central plane P). When the test subject enters the detector 1 and / or during step S1, the LEDs forming the shoe marks of the first set 8 are illuminated to guide and help correctly position the test subject in the first position on the detector 1 for acquiring a first electronic image in step S2. After step S2, these LEDs are turned off. After the LEDs forming the shoe marks of the first set 8 are turned off and before step S3 begins, the LEDs forming the shoe marks of the second set 9 are illuminated to ensure that the test subject is correctly positioned in the second position in step S3. In this way, the test subject is prompted to position himself / herself in the second position by rotating to place his / her feet on the shoe marks of the second set 9. Finally, before step S5, for example at the end of step S4, the LEDs forming the shoe marks of the second set 9 are turned off.

[0057] Of course, it will be understood that in an alternative embodiment, the shoe marks of the first set 8 and the shoe marks of the second set 9 may remain lit simultaneously throughout the detection method (for example, as shown in Figure 5), and the person being tested may be prompted to place their foot on either set by verbal instructions from a security guard or by announcements over a loudspeaker.

[0058] In a second embodiment, the indicator 7 of the detector 1 comprises a projector configured to project one or more images onto the inner surface 3 of one of the side panels 2 and / or onto the platform 4. The images projected onto the inner surface 3 may in particular have the function of providing information about the order of positions as well as the order of positions during the implementation of the detection method. The images projected onto the platform 4 may correspond to a first set 8 of shoe marks and a second set 9 of shoe marks, with successive projection steps onto the platform 4 corresponding to the switching on and off of the LEDs forming the first and second sets 9x of shoe marks as described in the first embodiment.

[0059] In a third embodiment, the indicator 7 of the detector 1 is audible and comprises a loudspeaker 10, which may be directly fixed to the detector 1 or located at a remote location. The loudspeaker 10 is also configured to emit an audible message to attract the test subject's attention. For example, when the test subject enters the detector 1 and / or during step S1, the loudspeaker 10 emits an audio message to guide the test subject and help them correctly position themselves in the first position of the detector 1 to acquire the first electronic image in step S2. After step S2, the loudspeaker 10 emits an audible message to guide the test subject to position themselves in the second position, for example, by making a quarter turn, to ensure that the test subject is correctly positioned in the second position. Optionally, after step S4, the loudspeaker may emit an audible message to guide the test subject to move away from the detector 1.

[0060] Alternatively, the security officer may verbally instruct the subject to move from the first position to the second position.

[0061] It will be understood that the first, second and third embodiments of the indicator 7 can be combined (combination of loudspeaker 10 or verbal instructions with lights 8, 9 and / or projector).

[0062] In step S5, the central unit 6 processes the first and second signals representative of the reflected radiant energy to generate one or more electronic images.

[0063] Typically, the central device 6 can generate one or more first electronic images and one or more second electronic images based on the first and second signals generated by the antenna 5 of each side panel 2 in steps S1 and S3, respectively (if each side panel 2 is equipped with a microwave antenna 5, it alternately acts as a transmitter and a receiver).

[0064] Alternatively, as will be seen below, the central unit 6 may be configured to generate a single electronic image based on the first and second signals, this single electronic image being "elliptical" or "unfolded" and capable of reproducing the surface of the subject over 360° (particularly if each side panel 2 is equipped with a microwave antenna 5).

[0065] To improve the efficiency and speed of the detection method, in one embodiment, in step S2.1 before step S4, first signals are transmitted to the central device 6. Preferably, these first signals are transmitted by the microwave antenna 5 as soon as they are acquired.

[0066] To further reduce the overall time required for the detection method, the central unit 6 processes the first signal as soon as it receives it (step S2.2). More specifically, the central unit 6 processes the first signal before receiving the second signal (see FIG. 4). In this manner, the central unit 6 begins processing the first signal while the test subject moves from the first position to the second position and while acquiring the second signal as needed. In this manner, when the central unit 6 receives the second signal, all or part of the first signal has already been processed (depending on the processing time of the first signal and the execution time of steps S3 and S4), allowing the processing of the second signal to begin immediately. Therefore, the processing results of the first and second signals are obtained more quickly.

[0067] Non-limiting examples are as follows: Acquiring the first and second signals (step S2) typically takes 0.05 to 0.5 seconds. The transmission of the first and second signals from the microwave antenna 5 to the central device 6 (steps S2.1 and S4.1) typically takes between 0.05 seconds and 0.5 seconds. The processing of the first and second signals (steps S2.2 and S4.2) takes 2 to 4 seconds.

[0068] Therefore, by transmitting and processing the first signal (steps S2.1 and S2.2) before and / or simultaneously with transmitting the second signal (step S4.1), the total time for detection method S can be reduced by 2 to 6 seconds. As a result, the security guard can obtain the signal processing results from the central device 6 by the time the person being inspected leaves the detector 1. This eliminates the need to keep the person being inspected waiting. Furthermore, the detector 1 becomes immediately available for inspection of a new person as soon as the person inspected by the detector 1 leaves.

[0069] Therefore, the detection method S of the present invention is more effective because it does not require an increase in the sensitivity of the detector 1 or the duration of the detection method S, and can reliably test all parts of the body of the subject.

[0070] Optionally, the detector 1 may further comprise a screen 11 configured to display the electronic image generated by the central unit 6. The screen 11 may be mounted on the detector 1, for example on one of the side panels 2 on the exit side of the detector 1, or may be located remotely and communicate with the central unit via a wireless or wired interface. Alternatively, a screen 11 may be mounted on each side panel 2.

[0071] In the embodiment shown in FIGS. 1 and 2, the inner surfaces 3 of the panels are curved, with the center of curvature facing the inner surface 3, to improve detection efficiency, particularly the ability of the detector 1 to locate the subject. More specifically, in this embodiment, the curvature of the inner surfaces 3 of the side panels 2 is such that the distance between the inner surfaces 3 in a plane perpendicular to the central plane P gradually increases from the entrance of the detector 1 to a maximum distance and then gradually decreases toward the exit of the detector 1. Alternatively, the inner surfaces 3 may be piecewise planar, with portions forming a passage that expands and contracts from the entrance to the exit. To this end, each of the inner surfaces 3 may, for example, have at least one flat portion inclined with respect to the central plane P so that the passage expands (with respect to the direction of the passage within the detector 1, i.e., from the entrance to the exit of the passage), a flat portion substantially parallel to the central plane P, and at least one portion inclined with respect to the central plane P so that the passage contracts toward the exit.

[0072] As can be seen, if the inner surface 3 of the side wall is curved (continuously or piecewise), the surface of the subject that can be easily reached by the microwaves increases, further improving the reliability of detection.

[0073] In the first embodiment, the central device 6 generates a single electronic image based on the first and second signals (step S5). This single electronic image therefore reproduces all of the information acquired by the central device 6 based on the first and second signals. If these first and second signals are generated by microwave antennas 5 present on the two side panels 2, the single electronic image is a representation of the elements identified by the detector 1 over the entire circumference (360°) of the person being inspected, and therefore comprises the front, back, and sides of the person being inspected. Thus, security personnel can obtain all the information they need to inspect an individual from a single image.

[0074] This single electronic image can be either elliptical (3D) or unfolded (2D).

[0075] In a second embodiment, the central unit 6 generates one or more first electronic images (one for each side panel 2 equipped with a microwave antenna 5) based on the first signal and one or more second electronic images (one for each side panel 2 equipped with a microwave antenna 5) based on the second signal (step S5). These electronic images may be displayed sequentially on the screen or may be combined to obtain a single electronic image and displayed on the screen.

[0076] If an object is identified by the central unit 6, it may be displayed on an electronic image and an alarm (audible and / or visible) may be generated by the detector 1.

[0077] Alternatively, to respect the privacy of the person being examined, the system may include software containing code instructions that automatically analyze the image and determine the presence or absence of abnormalities, which are displayed on an avatar representing the individual.

Claims

1. A detection method (S) for detecting an object using a detector (1) that utilizes radiant energy, the detector (1) including two opposing side panels (2) symmetrical with respect to a central plane (P) that is an imaginary plane, the side panels (2) being fixed and together defining a passageway; Step S1: placing a test subject at a first position in a passage between the two side panels (2) of the detector (1); a step S2 of acquiring a first signal representing radiant energy when the test subject is in the first position; Step S3: placing the subject at a second position different from the first position in the passage between the side panels (2) of the detector (1); a step S4 of acquiring a second signal representing radiant energy when the test subject is in the second position; Step S5 of generating an electronic image based on the first signal and the second signal to determine whether the subject is holding an object; Including, In one of steps S1 and S3, the subject is positioned facing one of the side panels (2) with their arms aligned with their body or spread in the central plane (P), and in the other of steps S1 and S3, the subject is positioned perpendicular to the two side panels (2) with their arms positioned away from their body so that they are spread in front of or to the sides at shoulder height (S).

2. The detection method (S) according to claim 1 , wherein the subject rotates through an angle different from 180° between the first position and the second position.

3. The detection method (S) according to claim 1 or 2, further comprising a step S6, before step S3, of sending an instruction to the test subject to move from the first position to the second position.

4. 4. The detection method (S) according to claim 3, wherein in step S6, the indication is visible and / or audible.

5. 5. The detection method (S) according to claim 3 or 4, wherein the instructions are transmitted by a central device (6) of the detector (1).

6. The detection method (S) according to claim 4 or 5, wherein the instructions are transmitted by a central device (6) of the detector (1), and in step S1, the subject is positioned facing one of the side panels (2), and in step S3, the subject is positioned perpendicular to the side panel (2).

7. The detection method (S) according to any one of claims 1 to 6, further comprising steps (S2.2; S4.2; S5) of processing the first signal and the second signal by a central device (6) so as to detect an object held by the person being examined.

8. 8. The detection method (S) according to claim 7, wherein before step S4, said first signal is transmitted (S2.1) to said central device (6).

9. 9. The detection method (S) according to claim 8, wherein during all or part of steps S3 and S4, the first signal is processed (S2.2).

10. The detection method (S) according to any one of claims 7 to 9, wherein the central device (6) combines the first signal and the second signal to generate a single electronic image of the subject.

11. A detector (1) that uses radiation energy, two opposing side panels (2) secured to one another and together defining a passageway; a radiant energy transducer (5), such as a microwave antenna, housed in at least one of the side panels (2); A detector (1) comprising a central device (6) adapted to carry out the detection method (S) according to any one of claims 1 to 10.

12. further comprising a visual and / or audible indicator (7), Detector (1) according to claim 11, wherein the central device (6) is configured to send instructions to the visible and / or audible indicator (7) to move the person being examined from a first position to a second position.

13. The visual indicator (7) one or more lights (8, 9) mounted on a platform (4) extending between the side panels (2); a projector configured to project one or more images onto the platform (4) and / or at least one side panel (2); and Detector (1) according to claim 12, comprising at least one means of a loudspeaker (10) adapted to emit an audible message to attract the attention of the person being examined.

14. Detector (1) according to any one of claims 11 to 13, wherein the side panels (2) each have an inner surface (3) facing the opposite side panel, the inner surface being curved.

Images