JP2023073001A - Passive imaging device - Google Patents

Abstract

To provide a passive imaging device that suppresses reception of electromagnetic waves radiated from an object other than a subject, and enables stable personal belonging inspection, for example, when used as a walk-through type personal belonging inspection device.SOLUTION: A passive imaging device is configured to generate a subject image by using four sensor units 3A to 3D arranged in a rectangular shape in plan view and receiving electromagnetic waves EW radiated from a subject S moving inside them. Each sensor unit 3A to 3D includes a housing having an electromagnetic wave transmission section and a receiving section that receives, in the housing, the electromagnetic waves that have transmitted through the electromagnetic wave transmission section. The electromagnetic wave transmission sections of the respective sensor units 3A to 3D are facing the sensor units diagonally opposite to them.SELECTED DRAWING: Figure 3

Description

The present invention relates to a passive imaging device that receives electromagnetic waves emitted from an object and produces an image of the object.

As an example of this type of passive imaging device, Patent Literature 1 describes a millimeter wave passive imaging device that obtains an image by receiving thermal noise (electromagnetic waves) in the millimeter wave band radiated from an object.

Passive imaging devices are also applied to security body scanners (personal belongings inspection devices) and the like because of their low invasiveness and high ability to detect hidden objects.

JP 2013-36867 A

When a person to be inspected (hereinafter referred to as a "subject") hides and carries an item, electromagnetic waves radiated from the body of the subject are blocked by the item at a certain portion of the item and are reduced. For this reason, the signal strength of the received electromagnetic wave is lower in the part with the article than in the part without the article. Therefore, in the passive imaging device applied to the belongings inspection device, the shape of the object appears as a dark silhouette in the image corresponding to the human body of the subject, and the shape of the silhouette that appears is the object (that is, the subject's It is possible to estimate the type of belongings).

The inventors are considering using a passive imaging device as a walk-through type belongings inspection device. In this case, the passive imaging apparatus is configured to include four sensor units Su1 to Su4 arranged in a rectangular shape in plan view, as shown in FIG. 11, for example. The passive imaging apparatus is configured such that each of the sensor units Su1 to Su4 receives electromagnetic waves emitted from the subject's body moving in the direction of the arrow inside them and generates an image of the subject. obtain.

However, in the passive imaging apparatus configured as described above, when each of the sensor units Su1 to Su4 receives electromagnetic waves radiated from an object other than the subject, an image of the subject is not correctly generated and stabilized. You may not be able to inspect your belongings.

Therefore, the present invention suppresses reception of electromagnetic waves radiated from objects other than the subject, and enables stable inspection of belongings when used as, for example, a walk-through type belongings inspection device. An object of the present invention is to provide a passive imaging device that

According to one aspect of the present invention, a passive imaging apparatus receives electromagnetic waves radiated from a subject moving inside the four sensor units arranged in a rectangular shape in plan view, and captures an image of the subject. configured to generate Each sensor unit has a housing having an electromagnetic wave transmitting portion, and a receiving portion for receiving the electromagnetic wave transmitted through the electromagnetic wave transmitting portion in the housing, and the electromagnetic wave transmitting portion of each sensor unit is diagonally located. facing the sensor unit.

According to the present invention, reception of electromagnetic waves radiated from objects other than the subject can be suppressed, and stable belonging inspection can be performed when used as a walk-through type belonging inspection device, for example. It is possible to provide a passive imaging device that

1 is a block diagram showing a schematic configuration of a passive imaging device according to an embodiment; FIG. 1 is a perspective view of a main part of a passive imaging device according to an embodiment; FIG. 1 is a plan view of a main part of a passive imaging device according to an embodiment; FIG. FIG. 4 illustrates first and fourth sensor units of a passive imaging device according to an embodiment; FIG. 3 illustrates second and third sensor units of a passive imaging device according to an embodiment; 3 is a block diagram showing a schematic configuration of first to fourth sensor units; FIG. 4 is a flow chart for explaining an example of the operation of the passive imaging apparatus according to the embodiment; 4 is a flow chart for explaining an example of the operation of the passive imaging apparatus according to the embodiment; FIG. 3 shows an example of the signal strength of a received electromagnetic wave, stored as an image (pixel) array; It is a figure for demonstrating the effect of the passive imaging device which concerns on embodiment. FIG. 11 is a diagram showing a configuration example when the passive imaging device is used as a walk-through type belongings inspection device;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1-3 show a passive imaging device 1 according to one embodiment of the invention. 1 is a block diagram showing a schematic configuration of the passive imaging device 1, FIG. 2 is a perspective view of the passive imaging device 1, and FIG. 3 is a plan view of the passive imaging device 1. As shown in FIG.

A passive imaging device 1 according to an embodiment is a device capable of receiving and imaging electromagnetic waves emitted from an object. In this embodiment, the passive imaging apparatus 1 is configured as a walk-through type belongings inspection apparatus, and is installed in a passage P, and a person (hereinafter referred to as "examinee S") who walks along the passage P in the direction of the arrow. receiving electromagnetic waves EW radiated from the human body HB to generate and display an image of the subject S (hereinafter referred to as "subject image").

In addition, the passive imaging apparatus 1 according to the embodiment determines whether or not the subject S possesses a specific article (mainly a dangerous article such as a knife, a gun, or an explosive) based on the generated subject image. It is configured to determine whether

In the following description, "front", "back", "left", and "right" mainly refer to directions based on the subject S (as seen from the subject S).

1 to 3, the passive imaging device 1 includes four sensor units (first to fourth sensor units 3A to 3D), a processing section 5, and a display section .

Each of the first to fourth sensor units 3A to 3D is configured to receive the electromagnetic wave EW emitted from the human body HB of the subject S and detect its signal strength. In this embodiment, the first to fourth sensor units 3A to 3D are arranged in a rectangular shape in plan view (see FIG. 3). In other words, the first to fourth sensor units 3A to 3D are arranged at the four corners of a rectangular area (indicated by two-dot chain lines in FIG. 3) in plan view.

Specifically, a first sensor unit 3A and a second sensor unit 3B are arranged on both sides of the passage P, and a third sensor unit 3C and a fourth sensor unit 3D are arranged on the first sensor unit 3A and the second sensor unit. It is installed on both sides of the passage P at a position on the rear side in the moving direction of the subject S relative to 3B. That is, the first sensor unit 3A and the fourth sensor unit 3D are positioned diagonally to each other, and the second sensor unit 3B and the third sensor unit 3C are positioned diagonally to each other. Then, the subject S moving along the passage P moves inside the first to fourth sensor units 3A to 3D.

FIG. 4 shows the first sensor unit 3A and the fourth sensor unit 3D located diagonally therefrom. FIG. 4(a) is a front view of the first and fourth sensor units 3A and 3D, and FIG. 4(b) is a sectional view taken along line AA of FIG. 4(a). FIG. 5 shows the second sensor unit 3B and the third sensor unit 3C located diagonally therefrom. FIG. 5(a) is a front view of the second and third sensor units 3B and 3C, and FIG. 5(b) is a cross-sectional view taken along line BB of FIG. 5(a).

As shown in FIGS. 4 and 5, the second and third sensor units 3B and 3C have a shape obtained by horizontally reversing the first sensor unit 3A (fourth sensor unit 3D). Other than that, however, the first to fourth sensor units 3A to 3D basically have the same components, so the first to fourth sensor units 3A to 3D will be collectively described below.

4 and 5, each of the first to fourth sensor units 3A to 3D has a casing (housing) 31. As shown in FIG. The front surface of the housing 31 is provided with an electromagnetic wave transmitting portion 32 that transmits electromagnetic waves, and a smooth surface portion 33 that is entirely or mostly formed as a smooth surface. The electromagnetic wave transmitting portion 32 is provided substantially in the center of the housing 31 in the width direction W and has a rectangular shape extending in the vertical direction V. As shown in FIG. The smooth surface portion 33 is provided adjacent to the electromagnetic wave transmitting portion 32 in the width direction W of the housing 31 and has a rectangular shape extending in the vertical direction V. As shown in FIG. In this embodiment, the length of the smooth surface portion 33 in the vertical direction V is larger (longer) than that of the electromagnetic wave transmitting portion 32 .

Although not particularly limited, in this embodiment, a relatively large opening extending in the vertical direction V is formed in the front center of the housing 31 , and this opening is closed by a plate-like closing member 34 . The closing member 34 is made of a material having a lower electromagnetic wave reflectance than other parts of the housing 31 . For example, if most of the housing 31 is made of metal, the closing member 34 can be made of synthetic resin. A rectangular hole extending in the vertical direction V formed in the closing member 34 is covered with an electromagnetic wave transmitting cover or the like to constitute the electromagnetic wave transmitting portion 32, which is indicated by a dashed line in FIGS. 4(a) and 5(a). The portion adjacent to one side of the rectangular hole in the width direction W (the left side in FIG. 4A and the right side in FIG. 5A) constitutes the smooth surface portion 33 .

Further, in the present embodiment, each of the first to fourth sensor units 3A to 3D has a temperature adjustment device 35 for maintaining the temperature of the smooth surface portion 33 at a predetermined temperature (for example, 32° C. or lower) lower than the normal temperature of a person. in the housing 31 . Although not particularly limited, the temperature adjustment device 35 includes a cooling unit 35a that is installed on the back surface of the smooth surface portion 33 and uses a Peltier element, a temperature sensor 35b that detects the temperature of the smooth surface portion 33, and a temperature sensor 35b that detects the temperature detected by the temperature sensor 35b. and a control unit 35c for controlling the cooling unit 35a (energization of the Peltier element) based on the above.

FIG. 6 is a block diagram showing a schematic configuration of the first to fourth sensor units 3A-3D. Referring to FIG. 6, in this embodiment, each of the first to fourth sensor units 3A to 3D has a polygon mirror 41, a condenser mirror 42, a receiving antenna 43, an amplifier 44, and a signal strength detector 45. ing. These constitute a receiving section that is housed in the housing 31 and receives the electromagnetic wave EW.

The polygon mirror 41 is arranged inside (directly behind) the electromagnetic wave transmitting portion 32 . The polygon mirror 41 is rotationally driven in the vertical direction V by an electric motor (not shown). The polygon mirror 41 is configured to reflect (scan) the electromagnetic wave EW emitted from the human body HB of the subject S and transmitted through the electromagnetic wave transmitting portion 32 toward (the light collecting surface of) the collecting mirror 42 . there is

The condenser mirror 42 is arranged below the polygon mirror 41 . The collecting mirror 42 is configured to collect the electromagnetic wave EW emitted from the human body HB of the subject S, transmitted through the electromagnetic wave transmitting portion 32 and reflected by the polygon mirror 41 to the receiving antenna 43 .

The receiving antenna 43 receives the electromagnetic waves EW condensed by the condensing mirror 42 . The amplifier 44 amplifies the electromagnetic wave EW received by the receiving antenna 43 and outputs it to the signal strength detector 45 . The signal strength detector 45 detects the signal strength of the electromagnetic waves EW input from the amplifier 44 . A detection result of the signal strength detection unit 45 is output to the processing unit 5 . In this embodiment, the amplifier 44 and the signal strength detection unit 45 are separately configured, but the signal strength detection unit 45 may include the amplifier 44 .

By the way, as described above, the first to fourth sensor units 3A to 3D are arranged in a rectangular shape in plan view (see FIG. 3). is arranged so as to face the diagonal sensor unit. More specifically, the electromagnetic wave transmitting portion 32 of each of the first to fourth sensor units 3A to 3D faces the smooth surface portion 33 of the diagonal sensor unit. Furthermore, in plan view, the electromagnetic wave transmitting portions 32 and the polygon mirrors 41 of the first to fourth sensor units 3A to 3D and the smooth surface portion 33 of the diagonal sensor unit are positioned on a straight line. .

For example, the electromagnetic wave transmitting portion 32 of the first sensor unit 3A faces the smooth surface portion 33 of the fourth sensor unit 3D, and the electromagnetic wave transmitting portion 32 of the fourth sensor unit 3D faces the smooth surface portion 33 of the first sensor unit 3A. are doing. Further, the electromagnetic wave transmitting portion 32 of the first sensor unit 3A, the polygon mirror 41 of the first sensor unit 3A, and the smooth surface portion 33 of the fourth sensor unit 3D are positioned on a straight line in plan view, and the electromagnetic waves of the fourth sensor unit 3D are aligned. The transmitting portion 32, the polygon mirror 41 of the fourth sensor unit 3D, and the smooth surface portion 33 of the first sensor unit 3A are positioned on a straight line in plan view.

Similarly, the electromagnetic wave transmitting portion 32 of the second sensor unit 3B faces the smooth surface portion 33 of the third sensor unit 3C, and the electromagnetic wave transmitting portion 32 of the third sensor unit 3C faces the smooth surface portion 33 of the second sensor unit 3B. facing each other. Further, the electromagnetic wave transmitting portion 32 of the second sensor unit 3B, the polygon mirror 41 of the second sensor unit 3B, and the smooth surface portion 33 of the third sensor unit 3C are positioned on a straight line in plan view, and the electromagnetic waves of the third sensor unit 3C are aligned. The transmitting portion 32, the polygon mirror 41 of the third sensor unit 3C, and the smooth surface portion 33 of the second sensor unit 3B are positioned on a straight line in plan view.

In this embodiment, the first sensor unit 3A detects electromagnetic waves EW emitted mainly from the front left half of the human body HB of the subject S as the subject S moves in the direction of the arrow P. The second sensor unit 3B mainly detects the front of the human body HB of the subject S as the subject S moves along the passage P in the direction of the arrow. It is configured to receive electromagnetic waves EW emitted from the right half.

Further, the third sensor unit 3C is designed to receive electromagnetic waves EW emitted mainly from the left half of the back of the human body HB of the subject S as the subject S moves in the direction of the arrow P. The fourth sensor unit 3D is configured to receive electromagnetic waves EW emitted from the right half of the back of the human body HB of the subject S as the subject S moves along the passage P. .

Here, in the present embodiment, the third sensor unit 3C and the fourth sensor unit 3D are provided with an entry detection sensor 51 for detecting the entry of the subject S, and the first sensor unit 3A and the second sensor unit 3B are provided. is provided with an advance detection sensor 52 for detecting the advance of the subject S (see FIG. 3). The entry detection sensor 51 is composed of, for example, a transmissive optical sensor, and includes a light projecting element 51A on the side of the third sensor unit 3C and a light receiving element 51B on the side of the fourth sensor unit 3D. Similarly, the advance detection sensor 52 is, for example, a transmissive optical sensor, and includes a light projecting element 52A on the first sensor unit 3A side and a light receiving element 52B on the second sensor unit 3B side. Also, each of the first to fourth sensor units 3A to 3D has a mirror angle detection sensor 53 for detecting the mirror angle of the polygon mirror 41 (see FIG. 6).

Returning to FIG. 1, the processing section 5 inputs the detection results of (the signal intensity detection section 45 of) the first to fourth sensor units 3A to 3D. Then, the processing unit 5, based on the detection results of the first sensor unit 3A and the second sensor unit 3B, which are positioned obliquely in front of the subject S moving along the passage P, determines the human body HB of the subject S. Based on the detection results of the third sensor unit 3C and the fourth sensor unit 3D, which are positioned obliquely behind the subject S moving on the passage P, the subject is An image of the back side of the human body HB of S is generated as an image of the subject. The subject image generated by the processing unit 5 (that is, the front side image and the back side image of the human body HB of the subject S) is output to the display unit 7 and displayed.

The subject image generated by the processing unit 5 (the subject image displayed on the display unit 7) is an image corresponding to the human body HB of the subject S. As shown in FIG. Here, when the subject S has an article hidden, as described above, the electromagnetic wave EW radiated from the body of the subject S is blocked by the article at a portion where the article exists. A portion with the article has a lower signal strength of the received electromagnetic wave EW than a portion without the article. As a result, in the subject image, the shape of the article (belongings) possessed by the subject S appears as a dark silhouette.

Further, in the present embodiment, the processing unit 5 determines that the subject S is a It is determined whether or not the user possesses the specific item. Then, when the processing unit 5 determines that the subject S possesses the specific item, the processing unit 5 notifies a host device (not shown) to that effect and/or via a notification unit (not shown) Notify the inspector.

That is, in the present embodiment, the processing unit 5 functions as an image generation unit that generates an image of the subject, and as a determination unit that determines whether or not the subject S possesses the specific item. It has a function.

However, it is not limited to this. The processing unit 5 does not have to determine whether the subject S possesses the specific article. In this case, the processing unit 5 functions as an image generation unit, and the inspector or the like displays the image of the subject displayed on the display unit 7 (the shape of the dark silhouette that appears in the image of the subject). It is determined whether or not the person S possesses the specific item.

Next, an example of operation of the passive imaging apparatus 1 will be described. 7 and 8 are flowcharts for explaining an example of the operation of the passive imaging apparatus 1. FIG.

When the entry detection sensor 51 detects the entry of the subject S (step S1; YES), the passive imaging apparatus 1 operates the first to fourth sensor units 3A to 3D (step S2). Specifically, the passive imaging apparatus 1 rotates the polygon mirrors 41 of the first to fourth sensor units 3A to 3D, and activates the signal intensity detectors 45, respectively. This enables the first to fourth sensor units 3A to 3D to receive the electromagnetic wave EW emitted from the human body HB of the subject S moving on the passage P and detect the signal strength SI.

Next, the passive imaging apparatus 1 receives the electromagnetic wave EW radiated from the human body HB of the subject S moving on the passage P by the first to fourth sensor units 3A to 3D, and detects the signal strength SI. . Specifically, in the passive imaging device 1, each of the first to fourth sensor units 3A to 3D receives data at predetermined intervals while the mirror angle of the polygon mirror 41 changes from the lower limit to the upper limit of the setting range. The signal intensity SI of the electromagnetic wave EW, that is, the signal intensity SI of the electromagnetic wave EW received for each mirror angle is detected (steps S3 to S8). Although not particularly limited, the predetermined angle can be appropriately set according to the number of pixels of the image generated by the passive imaging device 1 and the like.

Here, in the present embodiment, the setting ranges (lower and upper limits) of the mirror angles of the polygon mirrors 41 of the first to fourth sensor units 3A to 3D, in other words, the first to fourth sensor units 3A to 3D The electromagnetic wave reception range in the vertical direction V of (each of the receiving portions) is set based on the size in the vertical direction V of the smooth surface portion 33 of the diagonal sensor unit.

Specifically, for example, regarding the polygon mirror 41 of the first sensor unit 3A, the electromagnetic wave emitted at or near the top of the smooth surface portion 33 of the fourth sensor unit 3D diagonal to the first sensor unit 3A toward (the light-collecting surface of) the light-collecting mirror 42 of the first sensor unit 3A. A mirror angle that can reflect (scan) the electromagnetic wave radiated at or near the bottom toward (the light collecting surface of) the light collecting mirror 42 of the first sensor unit 3A can be set as the upper limit of the setting range.

As for the polygon mirror 41 of the second sensor unit 3B, the electromagnetic wave radiated from the uppermost part of the smooth surface portion 33 of the third sensor unit 3C or its vicinity, which is diagonally opposite to the second sensor unit 3B, is detected by the second sensor unit 3B. A mirror angle at which reflection (scanning) can be performed toward (the light-condensing surface of) the light-collecting mirror 42 of 3B is set as the lower limit of the setting range. A mirror angle at which the radiated electromagnetic waves can be reflected (scanned) toward (the light collecting surface of) the light collecting mirror 42 of the second sensor unit 3B can be set as the upper limit of the setting range.

Although description is omitted, the same applies to the polygon mirror 41 of the third sensor unit 3C and the polygon mirror 41 of the fourth sensor unit 3D.

Next, the passive imaging device 1 saves the signal intensity SI of the electromagnetic wave EW received for each mirror angle in each of the first to fourth sensor units 3A to 3D in the current time column of the image (pixel) array. (Step S9).

FIG. 9 shows an example of the signal strength SI of the electromagnetic wave EW received for each mirror angle, which is stored in step S9. In the example shown in FIG. 9, the column of the time "t-1" which is a predetermined time before the current time and the column of the time "t-2" which is a predetermined time before the current time have already been displayed for each mirror angle. The signal strength SI of the received electromagnetic wave EW is stored, and then a column of time "t+1" after a predetermined time from the current time, a column of "t+2" after a predetermined time, ... "t+n". , the signal strength SI of the electromagnetic wave EW received for each mirror angle can be stored.

Next, the passive imaging apparatus 1 determines whether advance of the subject S is detected by the advance detection sensor 52 (step S10). Then, if the advance of the subject S is not detected (step S10; NO), the passive imaging apparatus 1 returns to step S3 and repeats the processing of steps S3 to S11. As a result, the first to fourth sensor units 3A to 3D receive electromagnetic waves EW radiated from different parts of the human body HB of the subject S in the horizontal direction as the subject S moves along the passage P. Then, the signal strength SI is detected.

On the other hand, when the advance of the subject S is detected (step S10; YES), the passive imaging apparatus 1 creates the subject image ( A front side image and a back side image of the human body HB of the subject S are generated (step S11).

Specifically, in this embodiment, the passive imaging apparatus 1 detects the front left half of the human body HB of the subject S based on the signal strength SI of the electromagnetic wave EW received at each mirror angle in the first sensor unit 3A. An image is generated, and an image of the front right half of the human body HB of the subject S is generated based on the signal intensity SI of the electromagnetic waves EW received at each mirror angle in the second sensor unit 3B. Then, the passive imaging apparatus 1 synthesizes (combines) the generated front left half image and front right half image to generate a front side image of the subject's human body HB.

In addition, the passive imaging apparatus 1 generates an image of the left half of the back surface of the human body HB of the subject S based on the signal strength SI of the electromagnetic wave EW received by the third sensor unit 3C for each mirror angle. An image of the back right half of the human body HB of the subject S is generated based on the signal intensity SI of the electromagnetic wave EW received for each mirror angle in the unit 3D. Then, the passive imaging apparatus 1 generates a rear side image of the human body HB of the subject S by synthesizing the generated rear left half image and rear right half image.

Next, the passive imaging apparatus 1 performs edge extraction processing on the generated images (front side image and back side image) of the human body HB of the subject S to generate an edge image (step S12). The edge image is displayed on the display unit 7 (step S13).

Next, the passive imaging apparatus 1 determines whether or not the subject S possesses the specific article based on the generated edge images (the edge image of the front side image and the edge image of the back side image). (Determination of belongings) is performed, and if the subject S possesses the specific article, the host device is notified to that effect, or the inspector is notified to that effect (step S14). After that, the passive imaging apparatus 1 stops the first to fourth sensor units 3A to 3D (step S15), and ends this flow.

According to the passive imaging device 1 according to the embodiment, the following effects are obtained.

In the passive imaging apparatus 1 according to the embodiment, the electromagnetic wave transmitting portions 32 of the first to fourth sensor units 3A to 3D, which are arranged in a rectangular shape in plan view, face diagonal sensor units. Therefore, due to the presence of the diagonal sensor units, the first to fourth sensor units 3A to 3D may receive electromagnetic waves emitted from objects outside the first to fourth sensor units 3A to 3D. is suppressed. Therefore, the passive imaging apparatus 1 can generate an image of the subject with little noise, and the inspection of belongings can be performed stably and accurately.

In particular, when a plurality of passive imaging apparatuses are arranged side by side to inspect the belongings of many people, according to the passive imaging apparatus 1 according to the embodiment, as shown in FIG. The first to fourth sensor units 3A to 3D of the imaging apparatus 1 are prevented from receiving electromagnetic waves emitted from the human body of the subject of the adjacent passive imaging apparatus 1. FIG. Therefore, each passive imaging device 1 can generate a subject image with less noise about its own subject without being affected by the subject of the adjacent passive imaging device 1, and as a result , the belonging inspection of many people can be performed stably and accurately.

On the other hand, if the first to fourth sensor units 3A' to 3D' of the passive imaging device 1' are arranged arbitrarily, each passive imaging device 1' will have a The first to fourth sensor units 3A' to 3D' may receive electromagnetic waves radiated from the human body of the subject of the adjacent passive imaging apparatus 1'. In this case, the image of the subject generated by each passive imaging device contains noise, making it impossible to carry out a stable and accurate property inspection.

As described above, the passive imaging apparatus 1 according to the embodiment can generate an image of the subject with little noise not only when used alone but also when used in a plurality of arrays. This can contribute to stable and accurate product inspection.

In addition, in the passive imaging apparatus 1 according to the embodiment, the electromagnetic wave transmission portions 32 of the first to fourth sensor units 3A to 3D are opposed to the smooth surface portions 33 of the diagonal sensor units. Therefore, the first to fourth sensor units 3A to 3D are prevented from inadvertently receiving unnecessary electromagnetic waves other than the electromagnetic waves radiated from the human body HB of the subject S. A person image may be generated.

In addition, in the passive imaging device 1 according to the embodiment, the smooth surface portion 33 is made of a material having a lower electromagnetic wave reflectance than other portions of the housing 31 . Therefore, it is further suppressed that the first to fourth sensor units 3A to 3D inadvertently receive unnecessary electromagnetic waves other than the electromagnetic waves radiated from the human body HB of the subject S.

Moreover, in the passive imaging apparatus 1 according to the embodiment, the first to fourth sensor units 3A to 3D have a temperature adjustment device 35 that maintains the smooth surface portion 33 at a predetermined temperature lower than the normal human body temperature. Therefore, the image of the portion other than the subject image in the image generated by the passive imaging apparatus 1 is stabilized, and the difference between the subject image and the portion other than the subject image increases. A clear subject image is obtained.

In particular, in the passive imaging device 1 according to the embodiment, the reception range of electromagnetic waves in the vertical direction V of the first to fourth sensor units 3A to 3D is the size of the smooth surface portion 33 of the diagonal sensor unit in the vertical direction V. is set based on Therefore, it is further effectively suppressed that the first to fourth sensor units 3A receive electromagnetic waves emitted from objects outside the first to fourth sensor units 3A to 3D. The inadvertent reception of unnecessary electromagnetic waves other than the electromagnetic waves emitted from the human body HB of the subject S by the four sensor units 3A to 3D is further effectively suppressed, and/or the passive imaging device 1 A clearer image of the subject can be obtained by further stabilizing the portion other than the image of the subject in the generated image.

In the above-described embodiment, the first to fourth sensor units 3A to 3D use the polygon mirror 41 to receive the electromagnetic wave EW emitted from the human body HB of the subject S. However, it is not limited to this. Instead of the polygon mirror 41, the first to fourth sensor units 3A to 3D may use mirrors (scanning mirrors) having the same function as the polygon mirror 41, or scan the human body of the subject S using an array antenna. An electromagnetic wave EW emitted from the HB may be received.

Further, in the above-described embodiment, the passive imaging apparatus 1 performs the edge extraction processing on the images of the human body HB of the subject S (the front side image and the back side image), based on the edge image. is in possession of the specific item. However, it is not limited to this. The passive imaging apparatus 1 omits the edge extraction process (step S12) and determines whether or not the subject S possesses the specific article based on the image of the human body HB of the subject S. good too.

Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to the above-described embodiments and modifications, and further modifications and changes are possible based on the technical idea of the present invention. Of course there is.

Reference Signs List 1 Passive imaging device 3A to 3D First to fourth sensor units 5 Processing unit 7 Display unit 31 Housing 32 Electromagnetic wave transmission unit 33 Smooth surface unit 35 Temperature adjustment device 41... Polygon mirror, 42... Condensing mirror, 43... Receiving antenna, 44... Amplifier, 45... Signal strength detector, 51... Entrance detection sensor, 52... Advance detection sensor, 53... Mirror angle detection sensor, P... Passage, S... Subject, HB... Human body of subject

Claims (7)

Four sensor units arranged in a rectangular shape in a plan view are configured to receive electromagnetic waves emitted from a subject moving inside them and generate an image of the subject,
Each sensor unit has a housing having an electromagnetic wave transmitting portion, and a receiving portion for receiving an electromagnetic wave transmitted through the electromagnetic wave transmitting portion within the housing,
The electromagnetic wave transmitting portion of each sensor unit faces a diagonal sensor unit,
Passive imaging device. The housing further has a smooth surface,
The electromagnetic wave transmitting portion of each sensor unit faces the smooth surface portion of the diagonal sensor unit,
A passive imaging device according to claim 1 . 3. The passive imaging apparatus according to claim 2, wherein said smooth surface portion is made of a material having a lower electromagnetic wave reflectance than other portions of said housing. 4. The passive imaging apparatus according to claim 2, wherein each sensor unit has a temperature control device that maintains the smooth surface portion at a predetermined temperature lower than normal human body temperature. The passive according to any one of claims 2 to 4, wherein the electromagnetic wave reception range in the vertical direction of each sensor unit is set based on the vertical size of the smooth surface portion of the diagonal sensor unit. imaging device. The subject image includes a front side image and a back side image of the subject, and is used to determine whether the subject is carrying a specific item. 1. Passive imaging device according to one. The receiving unit
a polygon mirror that is driven to rotate in the vertical direction;
a signal intensity detection unit that detects the signal intensity of the electromagnetic wave emitted from the subject, transmitted through the electromagnetic wave transmission unit, and reflected by the polygon mirror;
including
generating the subject image based on the detection result of the signal strength detection unit;
The passive imaging device according to any one of claims 1-6.

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