Terahertz wave camera system and method for controlling the terahertz wave camera system

Abstract

To provide technology for checking the operation of transmission units.SOLUTION: A terahertz wave camera system has: transmission units that generate electromagnetic waves; a receiving unit that can detect the electromagnetic waves; and a processing unit that determines whether or not an output of the electromagnetic waves from the transmission units is equal to or more than a threshold based on first image information obtained by photographing the transmission units irradiating a subject with the electromagnetic waves.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a terahertz wave camera system. [Background technology]

[0002] Patent Document 1 describes a camera system that uses terahertz waves. Patent Document 1 describes an active terahertz wave camera system in which terahertz waves are generated from multiple terahertz wave light sources, the terahertz waves are irradiated onto a subject, and the terahertz waves reflected from the subject are detected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-087725 Summary of the Invention [Problem to be solved by the invention]

[0004] Terahertz waves are electromagnetic waves in an invisible wavelength band that cannot be seen by the human eye, so it is not possible for the human eye to confirm whether or not a light source is generating terahertz waves of the desired frequency.

[0005] Therefore, if some malfunction occurs in the light source or system and the desired terahertz waves are not generated from the light source, the subject cannot be photographed normally. Furthermore, terahertz waves of an unintended frequency may be generated due to oscillation caused by parasitic capacitance in the light source circuit. In this case, the same level of current as during normal operation flows through the light source circuit, so this abnormality cannot be detected even by monitoring the light source current. Thus, some means of confirming the operation of the terahertz wave light source is required.

[0006] The present invention has been made in view of the above problems, and has an object to provide a method for checking the operation of a transmitter using electromagnetic waves such as terahertz waves. [Means for solving the problem]

[0007] A terahertz wave camera system according to one aspect of the present invention is characterized by having a transmitter that generates electromagnetic waves, a receiver that can detect the electromagnetic waves, and a processor that determines whether the output of the electromagnetic waves from the transmitter is above a threshold value based on first image information obtained by capturing an image of the transmitter while irradiating the electromagnetic waves.

[0008] A control method for a terahertz wave camera system according to one aspect of the present invention is characterized by comprising the steps of: acquiring first image information of a transmitter irradiating electromagnetic waves; and determining, based on the first image information, whether the output of the electromagnetic waves from the transmitter is equal to or greater than a threshold value. [Effects of the Invention]

[0009] The present invention can provide a method for checking the operation of a transmitter using electromagnetic waves such as terahertz waves. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram illustrating the configuration of a terahertz wave camera system according to a first embodiment. [Figure 2] 2A to 2C are schematic diagrams illustrating an image captured by the terahertz wave camera system of the first embodiment and a processing method thereof. [Figure 3] 4 is a flowchart illustrating the operation of the terahertz wave camera system according to the first embodiment. [Figure 4] FIG. 2A is a schematic diagram illustrating the configuration of a terahertz wave camera system according to a second embodiment, and FIG. 2B is a schematic diagram illustrating an image captured by the terahertz wave camera system according to the first embodiment. [Figure 5] FIG. 10A is a schematic diagram illustrating the configuration of a terahertz wave camera system according to a third embodiment; FIG. 10B is a schematic diagram illustrating an image captured by the terahertz wave camera system according to the third embodiment; and FIG. 10C is a schematic diagram illustrating an image captured by the terahertz wave camera system according to the third embodiment. [Figure 6] FIG. 10 is a schematic diagram illustrating the configuration of a terahertz wave camera system according to a fourth embodiment. [Figure 7] FIG. 10 is a schematic diagram illustrating the configuration of a terahertz wave camera system according to a fifth embodiment. [Figure 8] 10(a) to 10(d) are schematic diagrams illustrating images captured by the terahertz wave camera system according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] First, let us explain terahertz waves. Terahertz waves are radio waves with any frequency band, typically ranging from 0.1 THz to 30 THz. Terahertz waves have a longer wavelength than visible light or infrared light, making them less susceptible to scattering from the subject and highly penetrating many materials. Furthermore, terahertz waves have a shorter wavelength than millimeter waves, allowing for high spatial resolution. Taking advantage of these characteristics, terahertz waves are expected to be applied to safe imaging technology as an alternative to X-rays. Specific examples of imaging technology that are expected to be applied include body checks in public places and surveillance cameras.

[0012] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. The terahertz wave camera system of each embodiment can be applied to body checks and surveillance cameras, which are expected to be used in such applications. Note that the following embodiments do not limit the present invention. Although the embodiments describe multiple features, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0013] (First embodiment) A terahertz wave camera system 1001 of this embodiment will be described with reference to FIGS.

[0014] 1 is a schematic diagram illustrating the configuration of a terahertz wave camera system 1001. The terahertz wave camera system 1001 has a receiving unit 100, a transmitting unit 103, a transmitting unit 104, a transmitting unit 105, a display unit 111, and a processing unit 110. In the terahertz wave camera system 1001 of this embodiment, the transmitting units 103 to 105 are arranged so that they are included within the angle of view that the receiving unit 100 can receive.

[0015] Each of the transmitters 103, 104, and 105 irradiates the subject 109 with terahertz waves. Here, irradiation can also be referred to as radiation. While the terahertz wave camera system 1001 includes multiple transmitters, the number of transmitters is not limited to one, two, or 16 or more. The frequency of the terahertz waves irradiated from the transmitters 103, 104, and 105 preferably includes any frequency component within the range of 0.1 THz to 30 THz, or preferably a single frequency. When the subject 109 includes a human body, since most clothing has high transparency up to 1 THz, a frequency of 0.3 THz to 1 THz is desirable for use in the inspection of concealed objects, etc. In this embodiment, a frequency band including 0.45 THz is used. The subject 109 is assumed to be moving along the traveling direction 112.

[0016] Transmitting unit 103 is provided with a plurality of transmitters 106, each emitting a terahertz wave. For example, transmitters 106 are arranged in a 2x2 array in transmitting unit 103. Transmitting unit 104 is provided with a plurality of transmitters 107, each emitting a terahertz wave. For example, transmitters 107 are arranged in a 2x2 array in transmitting unit 104. Transmitting unit 105 is provided with a plurality of transmitters 108, each emitting a terahertz wave. For example, transmitters 108 are arranged in a 2x2 array in transmitting unit 105. The arrangement and number of transmitters 106, 107, and 108 are appropriately selected depending on the intensity and directivity of the terahertz waves.

[0017] The transmitters 106, 107, and 108 are each composed of a single or multiple transmitting elements, and are mounted as a single chip in a housing. Here, the housing is also referred to as a package or mounting member. The transmitting elements can be semiconductor-type terahertz wave transmitting elements such as resonant tunneling diodes, or optically pumped terahertz wave transmitting elements. Furthermore, it is desirable that each transmitting element has an antenna structure to improve impedance matching with the atmosphere and terahertz wave generation efficiency. The size of the antenna is designed to be approximately the same as the wavelength to be used.

[0018] The receiving unit 100 is an element capable of detecting terahertz waves. The receiving unit 100 can also be called a camera for terahertz waves. The receiving unit 100 has a receiver 102 and an optical system 101. The receiver 102 is a sensor divided into multiple pixels. The optical system 101 focuses the terahertz waves on the receiving surface of the receiver 102. The optical system 101 can also form an image of the terahertz waves on the receiving surface of the receiver 102. The receiving unit 100 has a form similar to a camera in which the receiver 102 and the optical system 101 are integrated. However, the receiving unit 100 may also be installed in combination with the receiver 102 and the optical system 101 housed in separate housings.

[0019] The receiver 102 is composed of a single or multiple receiving elements and is mounted as a single chip in a housing. Here, the housing is also referred to as a package or mounting member. The receiving elements can be thermal-type detecting elements such as bolometers or semiconductor-type detecting elements such as Schottky barrier diodes. Here, since the receiver unit 100 detects images as a camera, the number of receiving elements can be referred to as the pixel count, and the size of the receiving elements can be referred to as the pixel size. For example, for applications such as concealed object inspection, the required pixel count is preferably 10,000 pixels or more. In other words, the receiver 102 can be considered an area sensor with 100 pixels x 100 pixels. Since the wavelength of terahertz waves is several hundred microns, the size of one receiving element conforms to this value. Therefore, the size of the receiver 102 is typically 10 mm x 10 mm or more. Considering resolution and size, the pixel count is preferably 20,000 pixels or more, and the size of the receiver 102 is several tens of millimeters or more on each side. The size may be 100,000 pixels or more and each side may be 500 mm or more. Furthermore, to improve impedance matching with the atmosphere and the detection efficiency of terahertz waves, it is desirable for each receiving element to have an antenna structure. The size of the antenna is designed to be approximately the same as the wavelength used.

[0020] The optical system 101 forms an image of the terahertz waves on the receiving surface of the receiver 102. The optical system 101 can be an optical element such as a lens or a mirror. When a lens is used, it is preferable to use a lens material that has low loss for the terahertz waves used. Examples of lens materials include Teflon (registered trademark) and high-density polyethylene. The optical system 101 is an imaging optical system, and its design can be based on visible light techniques. The dashed-dotted line in FIG. 1 indicates the optical axis of the optical system 101. The optical axis preferably coincides with the center of gravity of the receiving surface of the receiver 102. An aperture stop may also be provided inside the optical system 101. By narrowing the aperture stop, i.e., by increasing the F-number, the depth of field can be increased. In other words, an image of a wide range of the subject can be obtained. However, increasing the F-number may reduce the intensity of the terahertz waves passing through the optical system 101. It is preferable to adjust the aperture stop in consideration of the intensity of the terahertz waves from the transmitters 103, 104, and 105.

[0021] The processing unit 110 is a processing device such as a computer equipped with a CPU (Central Processing Unit), a memory, a storage device, etc. Image information acquired by the receiving unit 100 is sent to the processing unit 110, and signal processing is performed by the processing unit 110. The functions of the processing unit 110 may be provided in the receiving unit 100. The processing unit 110 can perform determination, signal processing, and control of the entire terahertz wave camera system, which will be described later. That is, the processing unit 110 may include a determination unit, a signal processing unit that processes signals, and a control unit. Furthermore, the processing unit 110 does not need to be a processing device such as a single computer, and at least some of the processing may be performed in the cloud. Furthermore, some of the processing may be performed by AI (Artificial Intelligence). In this embodiment, a form in which the processing unit 110 includes a determination unit, a signal processing unit, and a control unit is shown, but the determination unit, signal processing unit, and control unit may be provided separately.

[0022] The display unit 111 may be a monitor of a computer of the processing unit 110, or may be a device prepared for displaying images. The display unit 111 displays an image based on the image information formed by the processing unit 110.

[0023] 1, for the purpose of explaining this embodiment, it is assumed that there are the following transmitters. One of the transmitters, transmitter 107a, of transmitter unit 104 is assumed to not generate terahertz waves or to generate electromagnetic waves different from the desired frequency due to parasitic oscillation or the like. Furthermore, it is assumed that transmitter 108a of transmitter unit 105 generates terahertz waves of the desired frequency but with reduced intensity. Transmitters 107a and 108a are examples that assume the unlikely occurrence of a malfunction, and may be set for convenience's sake.

[0024] FIG. 2 is a schematic diagram illustrating images acquired by the terahertz wave camera system 1001 of FIG. 1. FIG. 2(a) shows an image of the subject 109. This image is taken as a main image, and for example, a concealed object is detected from this image. Main image refers to the case where the subject is photographed. In this embodiment, an image is shown taken in a direction perpendicular to the traveling direction 112 of the subject 109, i.e., an image of the side of the subject 109. The photographing direction may be changed depending on the application. The photographing direction can be determined by the direction of the optical axis of the optical system 101. In this embodiment, the receiving unit 100 is assumed to detect terahertz waves reflected by the subject 109, but it can also detect terahertz waves transmitted through the subject 109. Therefore, other positional relationships between the receiving unit 100 and the subject 109, as well as between the subject 109 and the transmitting units 103 to 105, can be changed as appropriate.

[0025] FIG. 2(b) shows an image of the transmitters 103-105. This image was taken when the subject 109 was not present or when the subject 109 was outside the angle of view of the receiver 100. The image in FIG. 2(b) is a two-dimensional distribution of light and dark images corresponding to the intensity of the terahertz waves generated by the transmitters 103-105. The higher the intensity, the brighter the image. In the image in FIG. 2(b), the same reference numerals are used to denote the parts corresponding to the transmitters 103-105 and the transmitters 106-108 in FIG. 1. Note that the images corresponding to the transmitters 106-108 have different brightness levels than the images corresponding to the transmitters 107a and 108a. FIG. 2(c) is a schematic diagram showing the output of terahertz waves at the dashed line 212 in FIG. 2(b). The vertical axis represents the output. The output can also be considered as intensity.

[0026] The portion corresponding to transmitter 107a in FIG. 2(b) is dark, indicating that there is no signal in the desired terahertz wave band. The output corresponding to transmitter 107a in FIG. 2(c) is 0. Therefore, it can be seen that transmitter 107a is not generating terahertz waves of the desired frequency. Furthermore, the portion corresponding to transmitter 108a in FIG. 2(b) is brighter than the portion corresponding to transmitter 107a, but darker than the other portions. The output corresponding to transmitter 108a in FIG. 2(c) is lower than the other outputs. Therefore, it can be seen that although terahertz waves of the desired frequency are being generated from transmitter 108, the intensity is reduced.

[0027] One method for detecting a drop in intensity is, for example, to determine whether a lower limit threshold 213 that is acceptable is determined in advance, as shown in FIG. 2(c), and then determine whether the intensity drops below this threshold. The output can be calculated based on the output intensity along the dashed line 212, which is a one-dimensional direction shown in FIG. 2(b), or by identifying regions in the image shown in FIG. 2(b) and setting the output based on the output of each region. The output of each region can be set arbitrarily, such as the sum of the pixel outputs of each region or the average value of the pixel outputs of each region. The output of each region can also be based on the output of only one pixel in each region. While this determination process is performed by the processing unit 110 in FIG. 1, a determination circuit may also be provided within the readout circuit of the receiver 102. In this manner, the transmitter inspection can be performed.

[0028] FIG. 3(a) is a flowchart illustrating the operation of the transmitter inspection. First, the operating state of the transmitter is confirmed (step S300). This confirms whether the transmitter is emitting terahertz waves. Depending on the operating state, a subflow for switching the operation of the transmitter may be performed. Also, a flow for skipping the next step S301 may be inserted depending on the operating state. Next, irradiation of terahertz waves begins (step S301). The transmitters 103 to 105 operate and irradiate terahertz waves. Note that if the transmitters are already in an irradiation state, the irradiation state is maintained. The irradiation state is also referred to as a bright state. Next, an image of the transmitters 103 to 105 is taken (step S302). The receiver 100 detects the terahertz waves irradiated from the transmitters 103 to 105. The image acquired in the irradiation state is also referred to as a bright image. From the detected signal or an image based on the signal, it is determined whether the output of the transmitters 103 to 105 is equal to or greater than a threshold (step S303). If it is equal to or greater than the threshold (Y), the inspection is completed. If the value is equal to or less than the threshold (N), for example, the processing unit 110 issues an instruction and displays a warning on the display unit 111 (step S304). Also, if the value is equal to or less than the threshold (N), for example, the processing unit 110 can perform an operation such as emitting an alert sound. By such an operation, it is possible to confirm the operation of the transmitting units 103 to 105, which cannot be seen with the naked eye.

[0029] Note that the image shown in FIG. 2(b) may be superimposed with spatial noise or shading due to the circuitry of the receiver 102. In this case, it is desirable to perform the following operation. FIG. 3(b) is a flowchart illustrating another operation of the transmitter inspection. The same operations in FIG. 3(b) as those in FIG. 3(a) will not be described again. First, the irradiation of terahertz waves is stopped (step S311). For example, the transmitters 103 to 105 stop operating, thereby stopping the irradiation of terahertz waves. Alternatively, the transmitters 103 to 105 operate to stop the irradiation of terahertz waves. Alternatively, a member that blocks terahertz waves is placed in front of the transmitters 103 to 105. Note that if the transmitters are already in a non-irradiation state, the non-irradiation state is maintained. The non-irradiation state is also referred to as a dark state. Next, the transmitters 103 to 105 are photographed in a non-irradiation state (step S312). The image photographed in a non-irradiation state is also referred to as a dark image. Next, the operations of steps S301 and S302 are performed. Then, signal processing (step S313) is performed. In signal processing, processing is performed to remove dark image information from bright image information. The dark image is a reference signal. In other words, signal processing is processing to remove the reference signal from the bright image. Next, a determination is made in the state in which signal processing has been performed (step S303), and the process is completed or step S304 is executed. By performing such processing, noise can be reduced, and the accuracy of the determination in step S303 can be improved. The improved accuracy of the determination can improve the accuracy of detecting malfunctions in the transmitting units 103 to 105.

[0030] When noise occurs randomly within a predetermined time period, the following operation can be performed. In the flow shown in FIG. 3(a), step S302 may be performed multiple times to average multiple bright images. Step S302 can be performed based on the averaged image. Furthermore, in the flow shown in FIG. 3(b), when noise occurs randomly within a predetermined time period, step S312 may be performed multiple times to average multiple dark images. In step S313, information about the averaged dark image can be removed from the bright image. Furthermore, in the flow shown in FIG. 3(b), when noise occurs randomly within a predetermined time period, step S302 and step S312 may each be performed multiple times to average multiple bright images and multiple dark images, respectively. In step S313, information about the averaged dark image can be removed from the averaged bright image. This process can reduce noise that occurs randomly over time. Therefore, the accuracy of detecting malfunctions of the transmitting units 103 to 105 can be improved.

[0031] Furthermore, in steps S301 and S302, the following operations may be performed. For example, in step S301, all of transmitting units 103 to 106 may be set to the checked state, and step S302 may be performed. Also, transmitting units 103 to 105 may be switched from the non-illuminated state to the illuminated state in rotation, and image capturing may be performed each time. That is, steps S301 and S302 may be performed multiple times by changing the operating states of transmitting units 103 to 105. First, in step S301, transmitting unit 103 is set to the illuminated state, and transmitting units 104 and 105 are set to the non-illuminated state. Then, step S302 is performed. Step S301 is performed again, transmitting units 103 and 105 are set to the non-illuminated state, and transmitting unit 104 is set to the checked state. Then, step S302 is performed. Step S301 is performed again, transmitting units 103 and 104 are set to the non-illuminated state, and transmitting unit 105 is set to the checked state. Then, step S302 is performed. A method may be used in which not only the transmitters 103 to 105 but also the transmitters 106 to 108 are turned on one by one in sequence and an image is taken each time. Alternatively, only a specific transmitter or transmitter may be turned on as an inspection target and an image may be taken.

[0032] The shooting in steps S302 and S312 may be one frame (still image), multiple discontinuous frames, or temporally continuous frames (moving image). In the case of a moving image, one frame's worth of data can be extracted from the image and processed.

[0033] Furthermore, information on the number and arrangement of transmitters and transmitters can be stored in advance in the processing unit 110. For example, information such as three transmitters 103 to 105, each having four transmitters in a 2x2 array, are lined up in a row. This information can be used to extract individual transmitters and transmitters from an image of the transmitters and transmitters. Also, AI can be used to extract individual transmitters and transmitters from an image. The AI ​​can be provided in the processing unit 110 or the cloud. This processing can display the status of the transmitters 103 to 105 on the display unit 111. This makes it possible to improve at least one of the efficiency and convenience of transmitter inspection.

[0034] Terahertz wave camera system 1001 may also have a spare transmitting unit (not shown). After step S304, the spare transmitting unit may be operated instead. After step S304, the output of each of transmitting units 103 to 105 may also be increased.

[0035] The operational flow of the transmitter inspection shown in Figures 3(a) and 3(b) can be performed when the terahertz wave camera system is installed at an operating location, when periodic maintenance is performed, or when the terahertz wave camera system starts operating. The transmitter inspection flow may also be performed each time actual imaging is performed. That is, after step S304, the operation can be transitioned to actual imaging.

[0036] The dark image acquired in step S312 can also be acquired by setting the transmitter in an emitting state. In this case, the receiver can be directed away from the transmitter, or a blocking section that blocks terahertz waves can be provided in the receiver or transmitter, and when acquiring a dark image, the blocking section can be moved between the receiver and transmitter. This operation allows the dark image to be acquired in a state where terahertz waves are not incident on the receiver. This method may be used if switching the transmitter state causes the operation of the transmitter or other parts to become unstable.

[0037] (Second embodiment) The terahertz wave camera system 1002 of this embodiment will be described with reference to FIG.

[0038] Fig. 4(a) is a schematic diagram illustrating the configuration of a terahertz wave camera system 1002. The terahertz wave camera system 1002 differs from the terahertz wave camera system 1001 of the first embodiment in the configuration of its optical system. An optical system 401 is obtained by adding an adjustment mechanism 402 for adjusting the focus to the optical system 101 of Fig. 1. Note that the same reference numerals as in the first embodiment are used for the components common to the first embodiment, and detailed descriptions thereof will be omitted.

[0039] The adjustment mechanism 402 can be used to focus on the subject 109 when photographing the subject 109, and can be used to focus on the transmitters 103 to 105 when inspecting the transmitters.

[0040] Fig. 4(b) is a diagram showing the image captured in Fig. 4(a). The symbols in Fig. 4(b) are the same as those in Fig. 2(b). The adjustment mechanism 402 allows the electromagnetic waves to be focused on the transmitters 103 to 105 for imaging. Therefore, a clearer image than the image in the first embodiment, i.e., a more accurate output, can be obtained.

[0041] With this configuration, it is possible to perform a highly accurate inspection of the transmitting units even in an arrangement in which the distance from the receiving unit 100 to the transmitting units 103 to 105 is different from the distance from the receiving unit 100 to the subject 109. Furthermore, it is possible to improve the degree of freedom in installing the transmitting units.

[0042] (Third embodiment) The terahertz wave camera system 1003 of this embodiment will be described with reference to FIG.

[0043] 5(a) is a schematic diagram illustrating the configuration of a terahertz wave camera system 1003. The terahertz wave camera system 1003 is obtained by adding a movable unit 500 that changes the direction of the receiving unit 100 to the terahertz wave camera system 1001 of the first embodiment. The terahertz wave camera system 1003 differs from the terahertz wave camera system 1001 in the number and arrangement of the transmitting units. Note that the same reference numerals as in the first embodiment are used for the components that are common to the first embodiment, and detailed descriptions thereof will be omitted.

[0044] The terahertz wave camera system 1003 has transmitters 501 to 506. The transmitters 501 to 503 are provided as a pair, and the transmitters 504 to 506 are provided as a pair. The subject 109 is located between the transmitters 501 to 503 and the transmitters 504 to 506. The receiver 100 is located between the transmitters 501 to 503 and the transmitters 504 to 506. The movable unit 500 is a member that changes the imaging direction of the receiver 100 and also a member that supports the receiver 100. When inspecting the transmitters 501 to 503, the movable unit 500 is rotated in direction A. When inspecting the transmitters 504 to 506, the movable unit 500 is rotated in direction B. The movable unit 500 operates upon receiving a signal from the processor 110. The movable unit 500 is capable of communicating with the processor 110. In FIG. 5( a ), the movable part 500 communicates with the processing part 110 via the receiving part 100 , but it may also communicate with the processing part 110 directly.

[0045] 5(b) and 5(c) are diagrams showing images captured using the configuration of FIG. 5(a). FIG. 5(b) is an image acquired when the movable unit 500 is rotated in direction A, and FIG. 5(c) is an image acquired when the movable unit 500 is rotated in direction B. FIG. 5(b) shows images corresponding to the transmitters 501 to 503. FIG. 5(c) shows images corresponding to the transmitters 504 to 506. Each white area corresponds to the transmitter of the respective transmitter. By using such a movable unit 500, a single receiver 100 can inspect multiple transmitters located in multiple directions. Note that, as in the arrangement of FIG. 5(a), if the irradiating surface of the transmitter and the receiving surface of the receiver are not aligned, the output of the transmitter detected by the receiver 100 may be low due to the directivity of the transmitter and the cosine law. In such cases, it is preferable to perform signal processing to correct the output before determining the output. Alternatively, it is desirable to change the threshold value. When taking pictures, the movable part 500 may be moved in the direction A or B while taking pictures continuously. As in the second embodiment, an adjustment mechanism may be provided in the optical system 101, or a wide-angle lens may be used. In this case, multiple transmitters may be captured in one image, but the resolution of each transmitter will decrease. Therefore, it is preferable to take the number of pixels into consideration when taking this into consideration.

[0046] Furthermore, when inspecting the transmitting units, a reflecting member may be provided at the position of subject 109. Terahertz waves irradiated from transmitting units 501 to 506 may be reflected by the reflecting member, and the reflected waves may be detected by receiving unit 100. By adjusting the position and angle of the reflecting member, it is also possible to inspect the light source by photographing each transmitting unit from the front.

[0047] Although the movable part 500 of this embodiment only rotates in directions A and B, that is, moves horizontally, it may move in any direction including up and down. Also, the structure of the movable part 500 may be a general structure.

[0048] As explained in this embodiment, by having the movable part 500 that changes the imaging direction, it is possible to efficiently inspect a plurality of transmitters in multiple directions.

[0049] (Fourth embodiment) The terahertz wave camera system 1004 of this embodiment will be described with reference to FIG.

[0050] Fig. 6 is a schematic diagram illustrating the configuration of a terahertz wave camera system 1004. The terahertz wave camera system 1004 is obtained by adding another receiving unit 600 to the terahertz wave camera system 1001 of the first embodiment. Note that the same components as those in the first embodiment are assigned the same numbers as those in the first embodiment, and detailed descriptions thereof will be omitted. Also, in Fig. 6, the processing unit 110 and the display unit 111 are not shown.

[0051] The receiving unit 600, like the receiving unit 100, has an optical system 601 and a receiver 602. Of the terahertz waves generated from the transmitting units 103 to 105, a component 650 reflected by the object 109 is imaged on the receiver 602, which detects the signal. In this embodiment, in order to detect the wave reflected from the object 109, the positions of the transmitting units 103 to 105, the object 109, and the receiving unit 600 are V-shaped as shown in FIG. 6. In other words, the direction connecting the transmitting units 103 to 105 and the object 109 intersects with the direction connecting the object 109 and the receiving unit 600. Here, the receiving unit 100 is provided to inspect the transmitting units 103 to 105. The transmitting unit inspection can be performed when the object 109 is not present.

[0052] With this configuration, the receiving unit 600 that takes an image of the subject 109 and the receiving unit 100 that performs the transmitting unit inspection are provided separately, so that each configuration can be simplified by fixing the focus and the imaging direction, and the transmitting unit inspection and imaging can be performed efficiently.

[0053] (Fifth embodiment) The terahertz wave camera system 1005 of this embodiment will be described with reference to FIGS.

[0054] FIG. 7 is a schematic diagram illustrating the configuration of a terahertz wave camera system 1005. The terahertz wave camera system 1005 is obtained by adding a receiving unit 700 and transmitting units 703 to 705 to the terahertz wave camera system 1001 of the first embodiment. The receiving unit 100 captures an image of the back of the subject 109, and the receiving unit 700 captures an image of the front of the subject 109. Note that components common to the first embodiment are assigned the same numbers as in the first embodiment, and detailed descriptions thereof will be omitted. Also, in FIG. 7, the processing unit 110 and the display unit 111 are not shown. FIG. 8 shows an image captured with the configuration of FIG. 7. In FIG. 8, the same numbers as those of corresponding components are assigned, as in FIG. 2(b).

[0055] In terahertz wave camera system 1005, the components are arranged as follows: Receiving unit 100 is arranged opposite transmitting units 103 to 105, and receiving unit 700 is arranged opposite transmitting units 703 to 705. The direction connecting receiving unit 100 and transmitting units 103 to 105 intersects with the direction connecting receiving unit 700 and transmitting units 703 to 705.

[0056] Similar to receiving unit 100, receiving unit 700 has optical system 701 and receiver 702. Of the terahertz waves generated from transmitting units 103 to 105, component 750 reflected by subject 109 is imaged on receiver 702, which then detects the signal.

[0057] The operation of the terahertz wave camera system 1005 will be described as follows with reference to FIG. 3(a). In steps S301 and S302, the receiver 100 captures images of the emitters 103-105, and the receiver 700 captures images of the emitters 703-705. Based on the acquired images, the emitters 103-105 and the emitters 703-705 are inspected. Steps S301 and S302 may be performed only on the emitters 103-105, only on the emitters 703-705, or on both, with the corresponding receiver 100 or receiver 700 being used. FIG. 8(a) shows an image of the emitters 103-105 captured by the receiver 100, and FIG. 8(b) shows an image of the emitters 703-705 captured by the receiver 700.

[0058] During actual imaging, the following operations are performed. The terahertz waves irradiated from the transmitters 103 to 105 are reflected by the front side of the subject 109, and the reflected component 750 is received by the receiver 700. This makes it possible to acquire an image of the front side of the subject 109. The terahertz waves irradiated from the transmitters 703 to 705 are reflected by the rear side of the subject 109, and the reflected component 751 is received by the receiver 100. This makes it possible to acquire an image of the rear side of the subject 109. FIG. 8(c) shows an image of the subject 109 when the receiver 700 images the subject 109, and FIG. 8(d) shows an image of the subject 109 when the receiver 100 images the subject 109.

[0059] In this way, terahertz wave camera system 1005, which can capture images of the front and back of subject 109, can capture images of subject 109 and inspect the transmitter. This leads to simplification of the entire terahertz wave camera system 1005, and enables efficient light source inspection.

[0060] Although several embodiments of the present invention have been described above, the present invention is not limited to these embodiments and various modifications and variations are possible within the scope of the gist thereof, and the configurations of the terahertz wave camera systems of the above-described embodiments can be used in combination with each other.

[0061] In each embodiment, the operations of the receiving unit, transmitting unit, and moving unit may all be systemized and automatically controlled. Specific examples include operations such as turning the transmitting unit on and off, changing the imaging direction by rotating the moving unit, adjusting the focus of the receiving unit, imaging, and periodic inspection of the transmitting unit. By freely combining and automating these operations, the workload on humans can be reduced. [Explanation of symbols]

[0062] 100 Receiver 101 Optical system 102 Receiver 103~105 Transmission Department 106~108 Transmitters 109 Subject 110 Processing section 111 Display section 1001 Terahertz Wave Camera System

Claims

1. a transmitter including a plurality of transmitters that generate terahertz waves; a receiving unit including a receiver capable of detecting the terahertz wave and having a plurality of pixels; a processing unit that determines whether or not an output of the terahertz wave from the transmitter is equal to or greater than a threshold value based on first image information obtained by capturing an image of the transmitter in a state where the transmitter is irradiating the terahertz wave, The processing unit is capable of controlling a first operation of capturing an image of the transmitter in a state where the transmitter is irradiating the terahertz waves, and a second operation of capturing an image of a subject using the terahertz waves from the transmitter in a state where the transmitter is irradiating the terahertz waves. A terahertz wave system characterized by:

2. each of the plurality of transmitters has a plurality of transmitting elements; The terahertz wave system according to claim 1 , wherein each of the plurality of transmitting elements has an antenna structure.

3. 3. The terahertz wave system according to claim 1, wherein the frequency band of the terahertz wave is 0.1 THz or more and 30 THz or less.

4. 4. The terahertz wave system according to claim 1, wherein the receiving unit has an optical system for focusing the terahertz waves.

5. 5. The terahertz wave system according to claim 4, wherein the optical system has a focus adjustment mechanism.

6. The terahertz wave system according to any one of claims 1 to 5, wherein the processing unit is capable of controlling a third operation of capturing an image of the transmitter in a state where the transmitter is not irradiated with the terahertz waves.

7. the first operation includes at least a step of checking a state of the transmitter and a step of capturing an image of the transmitter irradiating the terahertz wave, 7. The terahertz wave system according to claim 6, wherein the third operation is obtained by at least a step of checking the state of the transmitter and a step of photographing the transmitter in a state where the terahertz wave is not being irradiated.

8. The terahertz wave system according to claim 6 or 7, characterized in that the processing unit acquires the first image information by the first operation, acquires second image information by the third operation, and performs processing to remove the second image information from the first image information.

9. 9. The terahertz wave system according to claim 1, further comprising: a movable part on which the receiving part is provided and which is capable of changing the orientation of the receiving part.

10. The receiving unit is provided, and a movable unit is provided that can change the orientation of the receiving unit, 6. The terahertz wave system according to claim 1, wherein the processing unit is capable of controlling a first operation of photographing the transmitter while irradiating the terahertz waves, a third operation of photographing the transmitter while not irradiating the terahertz waves, and a fourth operation of controlling the movable unit to orient the receiver toward the transmitter before the first operation.

11. 11. The terahertz wave system according to claim 1, wherein the receiver has a size of 10 mm or more x 10 mm or more.

12. 12. The terahertz wave system according to claim 1, further comprising a transmitting unit separate from the transmitting unit.

13. 13. The terahertz wave system according to claim 12, wherein the processing unit is capable of controlling a fifth operation of simultaneously irradiating terahertz waves from the transmitting unit and the other transmitting unit.

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