Imaging equipment

Abstract

To provide an imaging device capable of stably inspecting belongings when used as a walk-through type belongings inspection device.SOLUTION: An imaging device includes: a signal strength detection part 20 for receiving an electromagnetic wave EW1 emitted from a human body HB of a moving subject S and reflected by a polygon mirror 10 and detecting signal intensity thereof; and a range finding part 30 for detecting a distance to the human body HB of the subject S, which irradiates the human body HB of the subject S with a range-finding electromagnetic wave EW2 and receives the range-finding electromagnetic wave (reflected electromagnetic wave) EW2 reflected by the human body HB of the subject S via the polygon mirror 10. The imaging device is configured to generate an image of the human body HB of the subject S based on the signal intensity and the distance from a processing part having an image generation function.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an imaging apparatus that receives electromagnetic waves emitted from a subject and creates an image (generates an image of the subject). [Background technology]

[0002] As an example of this type of imaging device, Patent Document 1 describes a millimeter-wave passive imaging device that obtains an image by receiving millimeter-wave thermal noise emitted from an object. Passive imaging devices have a high ability to detect hidden objects, and are therefore also used in security body scanners (personal item inspection devices).

[0003] In an imaging device applied to a personal belongings inspection device, when a subject is carrying a hidden object, the electromagnetic waves emitted from the subject's body are blocked by the object and reduced, resulting in a lower signal strength of the received electromagnetic waves in the area where the object is located compared to areas where there is no object. As a result, the shape of the object appears as a dark silhouette in the image with the human body in the background, and it is possible to estimate the type of the object (i.e., the subject's possessions) from the shape of this silhouette. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-36867 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors are considering using a passive imaging device as a walk-through personal belongings inspection device. In this case, the passive imaging device may be configured to include four sensing units Su1 to Su4 arranged at the four corners of a rectangular area in a plan view, as shown in FIG. 11 . Each sensing unit Su1 to Su4 faces the center of the rectangular area and is configured to receive electromagnetic waves emitted from the subject's body via a polygon mirror that is rotated, for example, in the vertical direction. When the subject moves within the rectangular area in the direction indicated by the arrow, each sensing unit Su1 to Su4 receives electromagnetic waves emitted from parts of the subject's body that are shifted in the left-right direction.

[0006] The image generated by such a passive imaging device is a horizontally arranged vertical line image obtained based on the electromagnetic waves received by each of the sensing units Su1 to Su4 during one scanning cycle of the polygon mirror. Here, N electromagnetic waves received at each predetermined angle while the reflective surface angle of the polygon mirror changes from the lower limit to the upper limit (or from the upper limit to the upper limit) of the set range constitute pixel data of the vertical line image.

[0007] However, as the subject moves, the distance between each sensing unit Su1-Su4 and the subject's body changes, which also changes the scanning range of the subject's body—that is, the range (vertical range) of the subject's body from which the sensing units Su1-Su4 can emit electromagnetic waves. For example, in the case of sensing unit Su1, as shown in FIGS. 12A-12C, as the distance between sensing unit Su1 and the subject's body decreases with the subject's movement, the scanning range of the sensing unit Su1 on the subject's body also decreases (time t0 → t4 → t9). This results in different imaging ranges between vertical line images, and if the subject is carrying an item, the proportion of the subject's belongings in the vertical line images changes. As a result, as shown in FIG. 13, the silhouette of the belongings that appears in the generated image (here, an image based on the electromagnetic waves received by sensing unit Su1 is shown) is distorted, and the silhouette no longer reflects the actual shape of the belongings, which may hinder reliable personal belongings inspection.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an imaging device that enables stable personal belongings inspection when used as a walk-through type personal belongings inspection device. [Means for solving the problem]

[0009] According to one aspect of the present invention, an imaging device is provided. , Scanmira reflected by and passes through the transmission and reflection plates. a signal strength detection unit that receives the electromagnetic wave and detects the signal strength; The electromagnetic wave for distance measurement is reflected by the transmission-reflection plate and the scan mirror and irradiated onto the subject, and the electromagnetic wave reflected by the subject is reflected by the scan mirror and the transmission-reflection plate and received. and a distance measuring unit that detects the distance to the subject, and is configured to generate an image of the subject based on the signal strength and the distance.

[0010] According to another aspect of the present invention, The imaging device four sensing units arranged at four corners of a rectangular area in a plan view, two on each side of a passage, each sensing unit being a polygon mirror that is rotated in a vertical direction; Transmitting and reflecting plates, The radiation emitted from the body of the subject moving through the passage 、 Reflected by the polygon mirror and passes through the transmission and reflection plate. a signal strength detection unit that receives the electromagnetic wave and detects the signal strength; The electromagnetic wave for distance measurement is reflected by the transmission-reflection plate and the polygon mirror and irradiated onto the body of the subject, and the electromagnetic wave reflected by the body of the subject is reflected by the polygon mirror and the transmission-reflection plate and received. the four sensing units having a distance measuring unit that detects the distance to the subject's body; an image generating unit that generates a front image of the subject's body based on the detection results of the signal strength detecting units and the distance measuring units of two sensing units positioned diagonally forward of the subject, and generates a back image of the subject's body based on the detection results of the signal strength detecting units and the distance measuring units of two sensing units positioned diagonally behind the subject; and a display unit that displays the front image and the back image of the subject's body generated by the image generating unit. include . [Effects of the Invention]

[0011] According to the present invention, an imaging device can be provided that, when used as a walk-through personal belongings inspection device, suppresses distortion of the silhouette of the subject's personal belongings that appears in the generated image, thereby enabling stable personal belongings inspection. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram illustrating a schematic configuration of an imaging apparatus according to an embodiment. [Figure 2] 1 is a perspective view of a main part of an imaging device according to an embodiment. [Figure 3] 1 is a plan view of a main part of an imaging device according to an embodiment. [Figure 4] FIG. 2 is a diagram illustrating a schematic configuration of a sensing unit of the imaging device according to the embodiment. [Figure 5] 10 is a flowchart illustrating an example of an operation of the imaging apparatus according to the embodiment. [Figure 6] 10 is a flowchart illustrating an example of an operation of the imaging apparatus according to the embodiment. [Figure 7]FIG. 2 is a diagram showing a coordinate system in the present embodiment. [Figure 8] FIG. 2 is a diagram showing a coordinate system in the present embodiment. [Figure 9] 1A and 1B are diagrams illustrating a portion of an image generated by an imaging device according to an embodiment. [Figure 10] FIG. 10 is a diagram illustrating a modified example of the imaging device according to the embodiment. [Figure 11] FIG. 10 is a diagram illustrating a configuration example in which a passive imaging device is used as a walk-through type personal belongings inspection device. [Figure 12A] 10A and 10B are diagrams for explaining problems that arise when a passive imaging device is used as a walk-through type personal belongings inspection device. [Figure 12B] 10A and 10B are diagrams for explaining problems that arise when a passive imaging device is used as a walk-through type personal belongings inspection device. [Figure 12C] 10A and 10B are diagrams for explaining problems that arise when a passive imaging device is used as a walk-through type personal belongings inspection device. [Figure 13] 10A and 10B are diagrams for explaining problems that arise when a passive imaging device is used as a walk-through type personal belongings inspection device. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0014] 1 to 3 show an imaging device 1 according to one embodiment of the present invention. Fig. 1 is a diagram showing a schematic configuration of the imaging device 1, Fig. 2 is a perspective view of a main part of the imaging device 1, and Fig. 3 is a plan view of a main part of the imaging device 1.

[0015] The imaging device 1 is a device that receives and images electromagnetic waves emitted from a subject such as a person or an object. In this embodiment, the imaging device 1 is configured as a walk-through personal belongings inspection device, and is configured to receive and image the electromagnetic waves EW1 emitted from the body HB of a person (hereinafter referred to as "subject S") walking down a passage P in the direction of the arrow, and to generate and display an image of the body HB of the subject S. The imaging device 1 is also configured to determine whether the subject S is carrying a specific item (mainly a dangerous object such as a knife, gun, or explosive) based on the generated image. In the following description, "front," "back," "left," and "right" refer to directions relative to the subject S (as seen from the subject S).

[0016] The imaging device 1 according to the embodiment includes four sensing units (first to fourth sensing units) 3A to 3D, a processing unit 5, and a display unit .

[0017] 4 shows a schematic configuration of the first to fourth sensing units 3A to 3D. As shown in FIG. 4, each of the first to fourth sensing units 3A to 3D has a polygon mirror 10, a signal intensity detection unit 20, and a distance measurement unit 30.

[0018] The polygon mirror 10 is driven to rotate in the vertical direction, and reflects electromagnetic waves EW1 emitted from the body HB of a subject S as an object by its reflective surface in a predetermined direction (toward a condenser mirror 21, which will be described later).

[0019] The signal intensity detection unit 20 receives the electromagnetic waves EW1 emitted from the body HB of the subject S and reflected by (the reflective surface of) the polygon mirror 10, and detects the signal intensity. In this embodiment, the signal intensity detection unit 20 includes a collecting mirror 21, a receiving antenna 22, an amplifier 23, and a detector 24. The signal intensity of the received electromagnetic waves EW1 may also be referred to as the reception level of the electromagnetic waves EW1.

[0020] The collecting mirror 21 collects the electromagnetic waves EW1 emitted from the body HB of the subject S and reflected by (the reflecting surface of) the polygon mirror 10 onto the receiving antenna 22. The receiving antenna 22 receives the electromagnetic waves EW1 collected by the collecting mirror 21. The amplifier 23 amplifies the electromagnetic waves EW1 received by the receiving antenna 22 and outputs them to the detector 24, which detects the signal intensity of the input electromagnetic waves EW1.

[0021] The distance measuring unit 30 detects the distance to the body HB of the subject S. In this embodiment, the distance measuring unit 30 includes a ToF (Time of Flight) distance measuring sensor 31, and detects the distance to the body HB of the subject S by irradiating the body HB of the subject S with electromagnetic waves (hereinafter referred to as "distance measuring electromagnetic waves") EW2 and receiving the distance measuring electromagnetic waves EW2 reflected by the body HB of the subject S.

[0022] Specifically, in this embodiment, the distance measuring unit 30 further includes a transmission-reflection plate 32 disposed downstream of the polygon mirror 10 in the propagation path of the electromagnetic waves EW1 radiated from the body HB of the subject S, specifically between the polygon mirror 10 and the collecting mirror 21. The transmission-reflection plate 32 is configured to transmit the electromagnetic waves EW1 radiated from the body HB of the subject S, while reflecting the distance measuring electromagnetic waves EW2. The distance measurement unit 30 is configured to irradiate the distance measurement electromagnetic wave EW2 emitted by the distance measurement sensor 31 onto the body HB of the subject S via the transmission / reflection plate 32 and the polygon mirror 10 (its reflective surface), and to receive the distance measurement electromagnetic wave EW2 reflected by the body HB of the subject S (in other words, the electromagnetic wave reflected by the body HB of the subject S) via the polygon mirror 10 (its reflective surface) and the transmission / reflection plate 32 by the distance measurement sensor 31, and to detect (measure) the distance to the body HB of the subject S based on the round-trip time of the distance measurement electromagnetic wave EW2.

[0023] 2 and 3, in this embodiment, the first to fourth sensing units 3A to 3D are arranged so as to be located at the four corners of a rectangular area (indicated by two-dot chain lines in FIG. 3) in a plan view, with two of the sensing units arranged on the left side of the aisle P and the remaining two sensing units arranged on the right side of the aisle P. Specifically, the first sensing unit 3A and the second sensing unit 3B are installed on both sides of the aisle P, and the third sensing unit 3C and the fourth sensing unit 3D are installed on both sides of the aisle P at positions rearward of the first sensing unit 3A and the second sensing unit 3B.

[0024] The first to fourth sensing units 3A to 3D are oriented substantially toward the center of the rectangular region in a plan view. Specifically, in this embodiment, the first to fourth sensing units 3A to 3D are arranged such that an orthogonal plane perpendicular to the reflective surface of the polygon mirror 10 forms a predetermined angle with respect to the direction of movement of the subject S (or the body HB).

[0025] In this embodiment, the first sensing unit 3A is configured to receive electromagnetic waves EW1 radiated mainly from the front left half of the body HB of the subject S as the subject S moves down the passage P in the direction of the arrow, detect the signal intensity, and detect the distance to the body HB of the subject S, and the second sensing unit 3B is configured to receive electromagnetic waves EW1 radiated mainly from the front right half of the body HB of the subject S as the subject S moves down the passage P in the direction of the arrow, detect the signal intensity, and detect the distance to the body HB of the subject S.

[0026] On the other hand, the third sensing unit 3C is configured to receive electromagnetic waves EW1 emitted mainly from the left half of the back of the body HB of the subject S as the subject S moves down the passage P in the direction of the arrow, detect the signal strength, and detect the distance to the body HB of the subject S, and the fourth sensing unit 3D is configured to receive electromagnetic waves EW1 emitted from the right half of the back of the body HB of the subject S as the subject S moves down the passage P, detect the signal strength, and detect the distance to the body HB of the subject S.

[0027] The third sensing unit 3C and the fourth sensing unit 3D are provided with an entry detection sensor 41 that detects the entry of the subject S, and the first sensing unit 3A and the second sensing unit 3B are provided with an exit detection sensor 42 that detects the exit of the subject S (see FIG. 3). The entry detection sensor 41 is, for example, a transmission type optical sensor, and includes a light-emitting element 41A on the third sensing unit 3C side and a light-receiving element 41B on the fourth sensing unit 3D side. Similarly, the exit detection sensor 42 is, for example, a transmission type optical sensor, and includes a light-emitting element 42A on the first sensing unit 3A side and a light-receiving element 42B on the second sensing unit 3B side.

[0028] In addition, each of the first to fourth sensing units 3A to 3D has an angle detection sensor 43 that detects the orientation of the reflective surface of the polygon mirror 10 with respect to the vertical direction, i.e., the angle between the vertical direction and the normal to the reflective surface of the polygon mirror 10 (hereinafter referred to as the "reflective surface angle of the polygon mirror 10") (see Figure 4).

[0029] Returning to FIG. 1, the processing unit 5 receives the detection results of the first to fourth sensing units 3A to 3D (the detection result of the signal intensity detection unit 20, the detection result of the distance measurement unit 30, and the detection result of the angle detection sensor 43). The processing unit 5 generates a front image of the body HB of the subject S based on the detection results of the first sensing unit 3A and the second sensing unit 3B positioned diagonally in front of the subject S moving through the passage P, and generates a back image of the body HB of the subject S based on the detection results of the third sensing unit 3C and the fourth sensing unit 3D positioned diagonally behind the subject S moving through the passage P. The front image and the back image of the body HB of the subject S generated by the processing unit 5 are output to the display unit 7 and displayed.

[0030] The image generated by the processing unit 5 (the image displayed on the display unit 7) is an image with the subject S's body HB as the background. Here, if the subject S is carrying a hidden object, as described above, the electromagnetic waves EW1 emitted from the subject S's body are blocked by the object in the area where the object is present. Therefore, the signal strength of the received electromagnetic waves EW1 is lower in the area where the object is present than in the area where the object is not present. As a result, the shape of the object (i.e., the object's possessions) appears in the image as a dark silhouette.

[0031] Furthermore, in this embodiment, the processing unit 5 determines whether or not the subject S is carrying the specific item based on the generated image of the body HB of the subject S, more specifically, based on (the shape of) a dark silhouette that appears in the image. If the processing unit 5 determines that the subject S is carrying the specific item, it notifies a host device (not shown) and / or notifies an examiner via a notification unit (not shown).

[0032] In other words, in this embodiment, the processing unit 5 has the function of an image generation unit that generates an image of the body HB of the subject S, and the function of a judgment unit that determines whether the subject S is carrying the specific item.

[0033] However, this is not a limitation. The processing unit 5 does not have to determine whether or not the subject S is carrying the specific item. In this case, the processing unit 5 functions as an image generating unit, and an examiner or the like determines whether or not the subject S is carrying the specific item based on the image displayed on the display unit 7 (the shape of a dark silhouette that appears in the image).

[0034] Here, a description will be given of an example of the operation of the imaging device 1. Figures 5 and 6 are flowcharts for explaining an example of the operation of the imaging device 1.

[0035] When the entrance of the subject S is detected by the entrance detection sensor 41 (step S1), the imaging device 1 operates the first to fourth sensing units 3A to 3D (step S2). Specifically, the imaging device 1 rotates the polygon mirrors 10 of the first to fourth sensing units 3A to 3D and activates the signal intensity detection unit 20 and the distance measurement unit 30. This enables the first to fourth sensing units 3A to 3D to receive the electromagnetic waves EW1 emitted from the body HB of the subject S and detect the signal intensity. Furthermore, the first to fourth sensing units 3A to 3D irradiate the body HB of the subject S with the distance measurement electromagnetic waves EW2 and receive the reflected electromagnetic waves EW2 from the body HB of the subject S via (the reflective surface of) the polygon mirror 10, thereby enabling them to detect the distance to the body HB of the subject S.

[0036] Next, the imaging device 1 detects the signal intensity of the electromagnetic wave EW1 emitted from the body HB of the subject S using the first to fourth sensing units 3A to 3D, and detects the distance to the body HB of the subject S. Specifically, in this embodiment, the imaging device 1 detects, in each of the first to fourth sensing units 3A to 3D, the signal intensity of the electromagnetic wave EW1 received at each predetermined angle while the reflecting surface angle of the polygon mirror 10 changes from the lower limit to the upper limit (or from the upper limit to the lower limit) of the set range, and the distance to the body HB of the subject S at that time (steps S3 to S8).

[0037] Next, the imaging device 1 stores the signal intensities of the electromagnetic waves EW1 detected in steps S3 to S8 for each of the first to fourth sensing units 3A to 3D as data in a polar coordinate system (step S9). Specifically, in this embodiment, the imaging device 1 stores the signal intensities of the electromagnetic waves EW1 detected in steps S3 to S8 as values ​​of each coordinate (r, θ, φ) in the polar coordinate system defined by the distance (=radius vector) r to the body HB of the subject S, the angle (=zenith angle) θ of the reflecting surface of the polygon mirror 10, and the angle (=azimuth angle) φ between the direction of movement of (the body HB of) the subject S and an orthogonal plane perpendicular to the reflecting surface of the polygon mirror 10.

[0038] Next, the imaging device 1 converts the stored data in the polar coordinate system into data in the Cartesian coordinate system (step S10). Specifically, in this embodiment, the imaging device 1 converts the signal intensity of the electromagnetic wave EW1 detected in steps S3 to S8 from the values ​​of each coordinate (r, θ, φ) in the polar coordinate system into the values ​​of each coordinate (x, y, z) = (rsinθcosφ,rsinθsinφ,rcosθ) in the Cartesian coordinate system. Here, the Cartesian coordinate system is a coordinate system in which the X axis is parallel to (opposite to) the direction of movement of the subject S, the Y axis is in the width direction of the passage P (from left to right), and the Z axis is directed vertically upward. Note that FIGS. 7 and 8 are diagrams showing coordinate systems (polar coordinates and Cartesian coordinates) in this embodiment.

[0039] Next, the imaging device 1 plots the signal intensity of the electromagnetic wave EW1 as data in a Cartesian coordinate system on a coordinate plane perpendicular to the direction of movement of the subject S (or the body HB) (step S11). Specifically, in this embodiment, the coordinate plane perpendicular to the direction of movement of the subject S (or the body HB) is the yz plane (see FIG. 8), and therefore the signal intensity of the electromagnetic wave EW1 acquired in steps S3 to S8 is plotted as the value of each coordinate (y, z) = (rsinθsinφ,rcosθ) on the yz plane. Here, one scanning cycle of the polygon mirror 10, i.e., the time it takes for the reflecting surface angle of the polygon mirror 10 to change from the lower limit to the upper limit (or from the upper limit to the lower limit), is short, and the subject S is located in approximately the same position during the processing of steps S3 to S8, so the value of the y coordinate is usually approximately the same.

[0040] Next, the imaging device 1 determines whether or not the advancement of the subject S is detected by the advancement detection sensor 42 (step S12). If the advancement of the subject S is not detected, the imaging device 1 repeats the processes of steps S3 to S11.

[0041] On the other hand, when the subject S's advance is detected, the imaging device 1 generates an image of the body HB of the subject S based on the signal intensity of the electromagnetic wave EW1 plotted on the coordinate plane (yz plane) (step S13). The generated image corresponds to a horizontal arrangement of vertical line images obtained based on the signal intensity of the electromagnetic wave EW1 received in one scanning cycle of the polygon mirror.

[0042] Specifically, in this embodiment, the imaging device 1 generates an image of the front left half of the body HB of the subject S based on the signal intensity of the electromagnetic wave EW1 detected by the first sensing unit 3A and plotted on the coordinate plane (yz plane), and generates an image of the front right half of the body HB of the subject S based on the signal intensity of the electromagnetic wave EW1 detected by the second sensing unit 3B and plotted on the coordinate plane (yz plane).The imaging device 1 then synthesizes (combines) the generated front left half image and front right half image to generate a front side image of the body HB of the subject S.

[0043] Furthermore, the imaging device 1 generates an image of the left half of the back surface of the body HB of the subject S based on the signal intensity of the electromagnetic wave EW1 detected by the third sensing unit 3C and plotted on the coordinate plane (yz plane), and generates an image of the right half of the back surface of the body HB of the subject S based on the signal intensity of the electromagnetic wave EW1 detected by the fourth sensing unit 3D and plotted on the coordinate plane (yz plane).The imaging device 1 then synthesizes the generated left half and right half back surface images to generate a back side image of the body HB of the subject S.

[0044] Next, the imaging device 1 applies edge enhancement processing to the generated images (front-side image and back-side image) of the body HB of the subject S to generate an edge-enhanced image (step S14), and displays the generated edge-enhanced image on the display unit 7 (step S15).

[0045] Next, the imaging device 1 determines whether or not the subject S is carrying the specific item (personal item determination) based on the generated edge-enhanced images (the edge-enhanced image of the front-side image and the edge-enhanced image of the back-side image), and if the subject S is carrying the specific item, notifies the host device or notifies the inspector of that fact (step S16). Thereafter, the imaging device 1 stops the first to fourth sensing units 3A to 3D (step S17), and ends this flow.

[0046] The operation and effects of the imaging device 1 according to the embodiment will be described. As described above, when a normal passive imaging device is used as a walk-through type personal belongings inspection device, the scan range on the body HB of the subject S changes as the subject S (body HB) moves. As a result, if the subject S is carrying an item, the silhouette of the item (the subject S's belongings) that appears in the generated image is distorted (see FIG. 13), and the silhouette no longer reflects the shape of the actual item (the subject S's belongings), which may result in the specific item being overlooked or erroneously detected, making it impossible to perform a stable personal belongings inspection.

[0047] In contrast, the imaging device 1 according to the embodiment receives electromagnetic waves EW1 emitted from the body HB of the moving subject S and reflected by a polygon mirror 10 rotating in the vertical direction, and detects the signal intensity. The imaging device 1 according to the embodiment detects the distance to the body HB of the subject S by irradiating the body HB of the subject S with ranging electromagnetic waves EW2 and receiving reflected electromagnetic waves, which are waves of the ranging electromagnetic waves EW2 reflected by the body HB of the subject S, via the polygon mirror 10. That is, the imaging device 1 according to the embodiment can acquire the signal intensity of the electromagnetic waves EW1 emitted from the body HB of the subject S and the distance to the part of the body HB of the subject S that emitted the electromagnetic waves EW1 (the source of the electromagnetic waves EW1). The imaging device 1 according to the embodiment generates an image of the body HB of the subject S based on the detected signal intensity and the detected distance.

[0048] Specifically, the imaging device 1 according to the embodiment first stores the signal intensity of the detected electromagnetic wave EW1 as data in a polar coordinate system defined by the distance r to the body HB of the subject S, the reflecting surface angle θ of the polygon mirror 10, and the angle φ between the moving direction of the subject S (or the body HB) and an orthogonal plane perpendicular to the reflecting surface of the polygon mirror 10. This allows the signal intensity of the electromagnetic wave EW1 to be accurately associated with the position of the source of the electromagnetic wave EW1. Next, the imaging device 1 according to the embodiment converts the stored polar coordinate system data into Cartesian coordinate system data and plots it on a coordinate plane perpendicular to the moving direction of the subject S (or the body HB). This allows the signal intensity of the electromagnetic wave EW1 to be associated with the position when the subject S is viewed from the front or back. The imaging device 1 according to the embodiment then generates an image of the body HB of the subject S based on the signal intensity of the electromagnetic wave EW1 plotted on the coordinate plane.

[0049] Therefore, as shown in Fig. 9, the silhouette of the belongings of the subject S that appears in the generated image is not distorted, and the shapes of the belongings of the subject S appear as silhouettes in the generated image. Note that Fig. 9 shows a part of the image (front side image of the body HB of the subject S) generated by the imaging device 1, and is an image based on the electromagnetic wave EW1 received by the first sensing unit 3A (an image corresponding to the image shown in Fig. 13).

[0050] Therefore, when the imaging device 1 according to the embodiment is used as a walk-through type personal belongings inspection device, the occurrence of overlooking or false detection of the specific items is suppressed, and stable personal belongings inspection can be performed.

[0051] In the above-described embodiment, the imaging device 1 (each of the sensing units 3A to 3D) receives the electromagnetic waves EW1 emitted from the body HB of the subject S by reflecting them off the polygon mirror 10 (the reflective surface thereof). However, this is not limited to this. The imaging device 1 may use a mirror (scan mirror) having the same function as the polygon mirror 10 instead of the polygon mirror 10.

[0052] Furthermore, in the above-described embodiment, the imaging device 1 determines whether or not the subject S is carrying the specific item based on an edge-enhanced image of the image of the subject S's body HB. However, this is not limited to this. The imaging device 1 may omit the edge enhancement process (step S14) and determine whether or not the subject S is carrying the specific item based on the image of the subject S's body HB.

[0053] In the above-described embodiment, the imaging device 1 includes an entry detection sensor 41 that detects the entry of the subject S and an exit detection sensor 42 that detects the exit of the subject S. However, this is not limited to this. As shown in FIG. 10 , the imaging device 1 may include a position detection sensor 44 that detects the position of the subject S, instead of the entry detection sensor 41 and the exit detection sensor 42. The position detection sensor 44 includes, for example, a plurality of transmission-type optical sensors arranged at intervals along the movement direction of the subject S, and is composed of a light-projecting unit 44A that is arranged on the left side of the passage P and incorporates a plurality of light-emitting elements, and a light-receiving unit 44B that is arranged on the right side of the passage P and incorporates a plurality of light-receiving elements corresponding to the plurality of light-projecting elements. The imaging device 1 may be configured to detect the entry and exit of the subject S based on the detection result of the position detection sensor 44, and to detect the movement speed of the subject S based on the detection result of the position detection sensor 44.

[0054] In this case, the imaging device 1 may be configured to expand or contract in the left-right direction (Y-axis direction) a vertical line image obtained based on the signal intensity of the electromagnetic wave EW1 received in one scanning cycle of the polygon mirror, depending on the moving speed of the subject S. For example, the imaging device 1 contracts the vertical line image in the Y-axis direction when the moving speed of the subject S is higher (faster) than a reference speed, and expands the vertical line image in the Y-axis direction when the moving speed of the subject S is lower (slower) than the reference speed. In this way, regardless of the moving speed of the subject S, an image of the body HB of the subject S can be obtained at approximately the same scale and without any omissions, thereby enabling more stable personal belongings inspection.

[0055] The above describes the embodiments and modifications of the present invention, but the present invention is not limited to the above-described embodiments and modifications, and it goes without saying that further modifications and changes are possible based on the technical concept of the present invention. [Explanation of symbols]

[0056] 1...imaging device, 3A to 3D...first to fourth sensing units, 5...processing unit (image generating unit), 7...display unit, 10...polygon mirror, 20...signal strength detecting unit, 21...condensing mirror, 22...receiving antenna, 23...amplifier, 24...detector, 30...distance measuring unit, 31...distance measuring sensor, 32...transmitting / reflecting plate, 41...entrance detection sensor, 42...exit detection sensor, 43...angle detection sensor, 44...position detection sensor, P...passageway, S...subject, HB...subject's human body (subject)

Claims

1. a signal intensity detection unit that receives electromagnetic waves emitted from a moving subject, reflected by a scan mirror, and transmitted through a transmission / reflection plate, and detects the signal intensity; a distance measuring unit that reflects electromagnetic waves for distance measurement by the transmission-reflection plate and the scan mirror and irradiates the object with the electromagnetic waves, and receives the electromagnetic waves reflected by the object by the scan mirror and the transmission-reflection plate, thereby detecting the distance to the object; and generating an image of the object based on the signal strength and the distance; Imaging equipment.

2. the scan mirror is a polygon mirror that is driven to rotate in the vertical direction, detecting an angle between a vertical direction and a normal to the reflecting surface of the polygon mirror as the reflecting surface angle of the polygon mirror; 2. The imaging device according to claim 1, wherein an image of the subject is generated based on the signal intensity, the distance, the angle of the reflecting surface of the polygon mirror, and the angle between the moving direction of the subject and an orthogonal plane perpendicular to the reflecting surface of the polygon mirror.

3. 3. The imaging apparatus according to claim 2, wherein the signal intensity is acquired as data in a polar coordinate system defined by the distance, the angle of the reflecting surface of the polygon mirror, and an angle between the moving direction of the subject and an orthogonal plane orthogonal to the reflecting surface of the polygon mirror, the acquired data is converted into data in a Cartesian coordinate system and plotted on a coordinate plane orthogonal to the moving direction of the subject, and an image of the subject is generated based on the signal intensity plotted on the coordinate plane.

4. the image of the subject corresponds to a horizontal arrangement of vertical line images obtained based on the signal intensities of the electromagnetic waves received in one scanning cycle of the polygon mirror; a moving speed of the subject is detected, and the vertical line image is enlarged or reduced in the left-right direction according to the moving speed of the subject; 3. The imaging device of claim 2.

5. 5. The imaging device according to claim 1, wherein the subject is a human body of a subject, and determines whether the subject is carrying a specific item based on an image of the subject.

6. four sensing units arranged at four corners of a rectangular area in a plan view, two on each side of a passageway, each sensing unit having a polygon mirror that is driven to rotate in a vertical direction, a transmission / reflection plate, a signal intensity detection unit that receives electromagnetic waves emitted from the body of a subject moving through the passageway, reflected by the polygon mirror, and transmitted through the transmission / reflection plate, and detects the signal intensity; and a distance measurement unit that reflects electromagnetic waves for distance measurement by the transmission / reflection plate and the polygon mirror, irradiates the body of the subject, and reflects the electromagnetic waves reflected by the body of the subject by the polygon mirror and the transmission / reflection plate, and receives the electromagnetic waves, thereby detecting the distance to the body of the subject; an image generating unit that generates a front image of the subject's body based on the detection results of the signal intensity detecting units and the distance measuring units of two sensing units positioned diagonally in front of the subject, and generates a back image of the subject's body based on the detection results of the signal intensity detecting units and the distance measuring units of two sensing units positioned diagonally behind the subject; a display unit that displays the front side image and the back side image of the subject's body generated by the image generation unit; 12. An imaging device comprising:

Images