JP2017040593A - Material identification apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material identification apparatus capable of performing an inspection of various types of concealed materials, including powder and a solid body of metal and the like, in a short time, for example, in an airport used by a number of passengers.SOLUTION: The material identification apparatus measures a signal of radiation energy of electromagnetic waves emitted by a detection object 60 that includes a material 63 to be detected, and identifies a type of the material 63 to be detected, which is included in the detection object 60, on the basis of a difference between the signal of the radiation energy emitted by the material to be detected and a signal of radiation energy of the detection object around the material to be detected. The material identification apparatus further calculates positional information of the material 63 to be detected, which is included in the detection object 60, and on the basis of the calculated positional information, irradiates the material 63 to be detected with the electromagnetic wave, thereby identifying the type of the material 63 to be detected on the basis of a signal of reflection energy from the material 63 to be detected.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a substance identification device for identifying a detection object included in a detection object, and in particular, a signal of radiation energy radiated by the detection object and a signal of radiation energy of a detection object around the detection object. The present invention relates to a substance identification device that can identify the type of a detection object included in a detection object from a difference.

  Security inspections are carried out to prevent the entry of materials, dangerous goods, etc. concealed under clothing for visitors at airports, public facilities, and event venues. In addition, entrance / exit inspections are also performed to prevent the removal of valuables, confidential information, goods, etc. at stores, companies, offices, etc. that handle expensive products.

  Usually, in a simple inspection, it passes through a gate with a built-in metal detector, and if necessary, an inspector checks whether there is a substance concealed under clothing by body touch. In recent years, in addition to these inspections, inspection methods using terahertz waves have been disclosed. Inspection using terahertz waves is known to be effective even for objects that cannot be detected by a metal detector.

  Here, prior art documents of a conventional substance identification device that detects an object to be detected by irradiating terahertz light that is an electromagnetic wave are shown below. For example, the specific substance detection device disclosed in Patent Document 1 irradiates an object to be detected with an electromagnetic wave (terahertz light) of 0.3 to 3 THz and detects the reflected light. In this specific substance detection apparatus, an optical filter that transmits only the spectral spectrum of the object to be detected is arranged on the optical path, and only the light reflected from the object to be detected is guided to the imaging unit, thereby detecting the object to be detected. It is the structure which detects.

  In addition, the object detection method disclosed in Patent Document 2 is configured to irradiate an object to be detected with 60 GHz electromagnetic waves and detect a reflected energy signal thereof. The object to be detected is detected from the pattern of peak change in each reflected energy when not being detected.

  Further, the personal authentication method disclosed in Patent Document 3 irradiates a human body with a radiation energy signal of electromagnetic waves radiated from a human body and an electromagnetic wave of 30 GHz to 30 THz, and measures the respective amplitudes of the reflected energy signals. The biometric information is extracted from the radiated energy and reflected energy of the electromagnetic wave, and the extracted biometric information is combined to authenticate the individual.

  In addition, the living body temperature measuring device disclosed in Patent Document 4 receives an electromagnetic wave signal radiated from a measurement part of a human body, further measures the conductivity or dielectric constant of the measurement part, and determines the conductivity or dielectric constant. A process for converting the measured value and the received electromagnetic wave signal into a temperature is performed, and the temperature at the part of the human body is measured.

JP 2005-265793 A JP 2000-009832 A JP-A-2005-270568 JP 2003-294535 A

  The comparison between the prior art document and the present invention will be described later in “Mode for Carrying Out the Invention”.

  However, the substance detection and substance identification apparatus disclosed in Patent Documents 1 to 3 irradiates the object to be detected with terahertz light, which is an electromagnetic wave, and detects and analyzes a signal of reflected energy from the object to be detected. Is. Since these substance detection and identification devices irradiate the entire object to be detected with electromagnetic waves of terahertz light, it takes time for detection. For this reason, many devices are required for inspection of concealed materials and dangerous materials at airports used by many passengers.

  Further, in Patent Document 1, in order to detect a specific substance, it is necessary to provide an optical filter that transmits only the spectrum of the detected object on the optical path. For this reason, detection of a wide range of substances from powders to solids such as metals is required. It was not suitable for.

  Therefore, the present invention measures the radiant energy signal of the electromagnetic wave radiated from the detection object including the detection object, and the radiant energy signal radiated by the detection object and the radiant energy of the detection object around the detection object. The type of the object to be detected included in the detection object is identified from the difference from the signal, and the object is irradiated with electromagnetic waves based on the position information of the object to be detected included in the detection object. An object of the present invention is to provide a substance identification device capable of identifying a detection object included in a detection object.

  In order to achieve the above-mentioned target, the substance identification device of the present invention measures the radiation energy signal of the electromagnetic wave emitted by the detection object including the object to be detected in the substance identification apparatus, and determines the radiation energy emitted by the object to be detected. The type of the detected object included in the detected object is identified from the difference between the signal and the signal of the radiant energy of the detected object around the detected object.

  Further, the substance identification device of the present invention is the substance identification apparatus further comprising: a signal of reflected energy from the detected object when irradiated with electromagnetic waves; and a reflected energy from the detected object when electromagnetic waves are not irradiated. The type of the detected object included in the detection object is identified from the difference from the signal.

  The substance identification device of the present invention relates to substance identification of the object to be detected, and uses at least one of the signals of the radiant energy or the reflected energy of electromagnetic waves.

  Further, the measurement of the radiant energy in the substance identification device of the present invention is performed by calculating a difference between a signal of radiant energy radiated by the detected object and a radiant energy of the detected object having a predetermined temperature around the detected object. It is characterized by measuring.

  In the substance identification device of the present invention, the detection object always has a substantially constant temperature.

  In the substance identification device of the present invention, the detection object is a moving or stationary human.

  In the substance identification device of the present invention, a substance having an emissivity of approximately 0 and a substance having an emissivity of approximately 1 are set as reference samples on the surface of a black body radiation plate having a predetermined temperature, and each of the reference samples is provided. The radiant energy signal of the reference sample and the radiant energy signal around the reference sample are measured, and the difference value of the radiant energy in each reference sample is calculated from the difference and stored as a reference value. The type of the object is identified by calculating a difference value from a difference between a signal of radiant energy radiated by the detected object and a signal of radiant energy of the detected object around the detected object, and calculating the difference value The relative value is calculated with reference to the reference value of the radiant energy from the above.

  In the substance identification device of the present invention, a substance having a reflectance of approximately 1 and a substance having a reflectance of approximately 0 are installed as reference samples on the surface of a black body radiation plate having a predetermined temperature and irradiated with electromagnetic waves. The signal of the reflected energy from each of the reference samples at the time and the signal of the reflected energy from each of the reference samples when no electromagnetic wave is irradiated are measured, and each difference value of the reflected energy in each of the reference samples is measured from the difference. Is calculated and stored as a reference value, and the type of the detected object is identified by the reflected energy signal reflected by the detected object when irradiated with the electromagnetic wave and the detected object when the electromagnetic wave is not irradiated. A difference value is calculated from a difference from a signal of reflected energy, and a relative value is calculated from the calculated difference value with reference to the reference value of the reflected energy.

  The electromagnetic wave in the substance identification device of the present invention is a terahertz wave having a frequency of 10 GHz to 10 THz.

  Further, the substance identification apparatus of the present invention includes a light source that emits electromagnetic waves, a beam adjuster that irradiates the object to be detected with electromagnetic waves from the light source, a signal of radiation energy and / or a reflected energy of the object to be detected. It is comprised from the detection apparatus which detects a signal, and the image processing and control apparatus which processes the signal from the said detection apparatus, It is characterized by the above-mentioned.

  In addition, the substance identification device of the present invention is a detection object included in a detection object from a difference between a signal of radiant energy radiated by the detection object and a signal of radiant energy of a detection object around the detection object. The position information is calculated, and the detected object is irradiated with the electromagnetic wave based on the calculated position information.

  In addition, the substance identification device of the present invention includes an imaging unit that images the detection target, and the difference between the signal of the radiant energy of the detection target and an image of the detection target captured by the imaging unit In addition, a display unit that displays the image by superimposing the difference of the reflected energy signals is provided.

  Further, the image processing / control device in the substance identification device of the present invention controls the light source, and emits electromagnetic waves from the light source based on a signal of radiation energy and / or a signal of reflected energy from the detected object. The strength is controlled.

  According to the present invention, the difference between the signal of the radiant energy radiated by the detected object and the signal of the radiant energy of the detected object around the detected object is detected. Thereby, it becomes possible to identify the type of the detected object included in the detected object. For example, it is possible to identify that the substance concealed under the person's clothes is powder, paper, or metal.

  In addition, since the position of the object to be detected can be specified by the radiant energy, the signal of the reflected energy from the object to be detected is reliably obtained by irradiating the electromagnetic wave based on the range including the position specified by the radiant energy. Can be obtained. For this reason, since it is not necessary to detect the electromagnetic wave of the whole detection target object, a to-be-detected object can be identified in a short time.

  In addition, calibration of terahertz wave radiant energy and reflected energy is performed, and the relative value that is the standard for each substance type is stored in the database, and the type of substance is determined by referring to the database from the measurement results of radiant energy and reflected energy. This makes it possible to identify a stable substance.

  In addition, the terahertz wave detection unit in the body scanner receives the signal of the terahertz wave radiant energy from the inspected person, and simultaneously images the inspected person with a CCD camera as an imaging device, and the terahertz wave detecting unit Identify the substance possessed by the examinee by high-speed image processing of the radiant energy signal and the image of the CCD camera to recognize the shape, and then irradiate the terahertz wave and process the reflected energy signal from the substance Process. As a result, the control computer aligns the image obtained by the terahertz wave detection unit and the image of the CCD camera, and an image obtained by superimposing the image of the terahertz wave detection unit on the image of the CCD camera is displayed on the display device. For this reason, it becomes possible to easily confirm the substance possessed by the subject.

  In addition, if there is identification information based on the difference in intensity of each signal of terahertz wave radiant energy and reflected energy from the object to be detected, if there is something corresponding to an alarm, an alarm sound is generated and the identification information is used for each color. It can be displayed, and anomalies can be notified by sound and images.

It is a block diagram which shows the structure of the substance identification apparatus of this invention. It is a block diagram which shows the structure of a body scanner. It is a block diagram which shows the structure of an image processing / control apparatus. It is a flowchart which shows the process of the calibration of the radiation energy regarding the substance identification apparatus, and reflected energy. It is a table | surface which shows the relative value of the radiant energy and reflected energy for every identification material memorize | stored in the database for identifying a substance, (a) shows the relative value of radiant energy, (b) shows the reflected energy. Indicates a relative value. It is a flowchart which shows the detection process of the to-be-detected object by a substance identification apparatus. It is a figure which shows the display example of the image of the radiation energy signal in the detection process of a concealment object, and the display apparatus of a CCD camera, and the terahertz image, the CCD camera image, and identification information for each color are superimposed on the left side of the image, and on the right side The example of a display which superimposed the CCD camera image and the identification information according to color is shown. It is a figure which shows an example of the measurement data of the arbitrary values of the radiation energy in a to-be-detected object, and reflected energy.

  Hereinafter, an embodiment for carrying out a substance identification device according to the present invention will be described with reference to the drawings. The substance identification device according to the present invention determines the type of the detected object included in the detected object from the difference between the signal of the radiant energy radiated by the detected object and the signal of the radiant energy of the detected object around the detected object. Further, the object to be detected is identified by irradiating the object with electromagnetic waves based on the position information of the object to be detected included in the object to be detected.

  FIG. 1 is a block diagram showing a configuration of a substance identification apparatus according to the present invention, FIG. 2 is a block diagram showing a configuration of a body scanner, and FIG. 3 is a block diagram showing a configuration of an image processing / control apparatus.

[Configuration of substance identification device]
As shown in FIG. 1, the substance identification device 1 includes a body scanner 2, a terahertz light source 45, a beam adjuster 50, an image processing / control device 30, a control computer 55, and a display device 57. Yes.

  As shown in FIG. 1 and FIG. 2, the body scanner 2 is irradiated with a terahertz wave radiation energy radiated from the inspected person 60 and the detected object 63 as the detection target 60 and the terahertz light source 45 to detect the detected object 63. Is provided with a terahertz wave detection unit 3 that detects the reflected energy of the terahertz wave reflected by.

  The body scanner 2 converts the magnitude of the terahertz wave energy detected by the terahertz wave detection unit 3 into a digital value, and the converted digital value of the terahertz wave energy is supplied to the image processing / control device via the control / signal output unit 18. Output to 30.

  The radiant energy refers to terahertz wave energy radiated from the detection object 60 and the detection object 63. On the other hand, the reflected energy refers to the energy of the terahertz wave that irradiates the detection target 60 and the detection target 63 with terahertz waves and reflects from the detection target 60 and the detection target 63. Further, the detected object 63 refers to a substance such as powder or metal concealed under clothing by the inspected person 60.

  The body scanner 2 has a built-in CCD camera 15 as the imaging device 15, and the CCD camera 15 is a detection target in an area (space) including a detection area 65 (see FIG. 7) detected by the terahertz wave detection unit 3. 60, and a video signal obtained by imaging the detection object 60 is output to the image processing / control device 30. Details of the body scanner 2 will be described later.

  The terahertz light source 45 is a light source for irradiating the detection target 63 with terahertz waves, and irradiates terahertz waves in the vicinity of 250 GHz, for example, in accordance with the frequency sensitivity of the terahertz wave detection unit 3. The terahertz light source 45 is configured so that the image processing / control device 30 can control the output magnitude of the terahertz wave (electromagnetic wave) and the ON / OFF of the electromagnetic wave output.

  The beam adjuster 50 adjusts the terahertz beam by irradiating the terahertz wave in a predetermined direction, expanding, narrowing, or changing the polarization. The beam adjuster 50 may be, for example, a biaxial gimbal mirror that changes the rotation angle of the horizontal axis and the vertical axis, reflects a terahertz wave, and irradiates the detection target 63.

  The image processing / control device 30 processes the terahertz wave signal detected by the body scanner 2 to emit a signal of the radiant energy radiated from the detected object 63 and the radiant energy of the detected object 60 around the detected object 63. The type of the detected object 63 included in the detection target 60 is identified from the difference from the signal.

  Further, the image processing / control device 30 detects the reflected energy signal of the detected object 63 detected by the body scanner 2 when the electromagnetic wave is irradiated by the terahertz light source 45 and the detected object when the electromagnetic wave is not irradiated. The type of the detected object 63 is identified from the difference from the reflected energy signal of the object 63. Details of the image processing / control device 30 will be described later.

  The control computer 55 performs overall control of the substance identification device 1 and control of the image processing / control device 30. A display device 57 is connected to the control computer 55, and the display device 57 detects the detected object 63 included in the inspected person (detected object) 60 processed by the image processing / control device 30. It is displayed superimposed on the image captured in step (b). Further, the display device 57 can also display a dangerous object, a concealed object, and the like on the detected object 63 with an alarm superimposed on the image of the CCD camera 15.

[Body scanner configuration]
Next, the body scanner 2 of the substance identification device 1 will be described in detail with reference to FIG. As shown in FIG. 2, the body scanner 2 controls the positions of the terahertz wave detector 8 that detects the terahertz wave, the scan mirror 20, the imaging device (CCD camera) 15, and the scan mirror 20, and detects the terahertz wave. And a control / signal output unit 18 for outputting signals from the image sensor 8 and the imaging device 15 to the image processing / control device 30. The terahertz wave detector 8 and the scan mirror 20 constitute a terahertz wave detection unit 3.

  The terahertz wave detector 8 detects a terahertz wave from the detection object 60 and the detection object 63, receives the terahertz wave with an antenna, and detects the terahertz wave with a solid element such as a diode.

  The terahertz wave detection unit 3 includes, for example, a plurality of the same terahertz wave detectors 8, and a plurality of antennas are provided. The scan mirror 20 obtains a two-dimensional signal from the plurality of terahertz wave detectors 8. be able to.

  The detected terahertz wave signal is amplified by an amplifier and output to the control / signal output unit 18.

  The scan mirror 20 reflects the terahertz wave from the detection target (inspected person) 60 in the detection area 65 (see FIG. 7) and guides it to the terahertz wave detector 8, and reflects the terahertz wave. A mirror (not shown) is provided, and the attitude of the mirror is controlled by a mirror control motor (not shown).

  The mirror control motor that drives the mirror is controlled by the control / signal output unit 18.

  Thereby, the control / signal output unit 18 can control the attitude of the mirror and obtain a two-dimensional signal.

  As described above, the scan mirror 20 controls the mirror so that the electromagnetic wave from the predetermined position in the two-dimensional inspection area is guided to the terahertz wave detector 8.

  For this reason, when the scan mirror 20 sequentially scans the two-dimensional inspection area, it is possible to receive electromagnetic waves from the entire area of the inspection area. Further, the scan mirror 20 can be controlled to receive an electromagnetic wave at a predetermined position in the two-dimensional inspection area.

  The space to be inspected is imaged by the CCD camera 15 as the imaging device 15, and the imaging signal imaged by the CCD camera 15 is output to the control / signal output unit 18. The imaging device 15 is not limited to the CCD camera 15 and may be a camera using other solid elements.

  As shown in FIG. 2, the control / signal output unit 18 performs image processing / control on the terahertz wave signal detected by the terahertz wave detection unit 3 of the body scanner 2 and converted into a digital value and the imaging signal of the CCD camera 15. Output to device 30.

[Configuration of Image Processing / Control Device]
Next, an image processing / control apparatus (also referred to as an image processing / control apparatus) will be described in detail with reference to FIG. FIG. 3 is a block diagram showing the configuration of the image processing / control apparatus. As shown in FIG. 3, the image processing / control device 30 inputs a signal from the body scanner 2 to the image processing unit 32 via the input unit 31. At this time, signals output from the body scanner 2 are a terahertz wave digital signal detected by the terahertz wave detector 8 and an imaging signal from the imaging device (CCD camera) 15.

  The image processing unit 32 stores the magnitude of the terahertz wave digital signal at each position based on the two-dimensional position information of the terahertz wave digital signal. Further, the area of the subject 60 is cut out from the imaging signal of the imaging device 15, and the magnitude of the digital signal of the terahertz wave at each position in the area of the detection target (subject) 60 is extracted. Thereby, the detection area 65 (see FIG. 7) of the subject 60 is determined, and the magnitude of the terahertz wave digital signal in the detection area 65 is determined.

  The determination processing unit 33 calculates a relative value from the difference processing of the radiant energy and reflected energy signals, and refers to the detected object 63 (see FIG. 5A and FIG. 5B) with reference to the database shown in FIGS. (Concealment) is determined.

  The space to be inspected is picked up by the image pickup device (CCD camera) 15, and the processed terahertz wave signal is superimposed on the image pickup signal of the CCD camera 15 and an image is displayed on the display device 57 connected to the control computer 55. Can be displayed as

  Note that the position (area) of the space detected by the terahertz wave detection unit 3 of the body scanner 2 is set on the space imaged by the CCD camera 15. For example, two centers of the imaging area of the CCD camera 15 are set. By setting coordinates in the X-axis and Y-axis directions as the origin of the three-dimensional XY coordinate axes, the magnitude of the detection signal of the terahertz wave detection unit 3 of the body scanner 2 corresponding to the XY coordinate values of the CCD camera 15 image is calculated. can do.

  The image processing unit 32 of the image processing / control device 30 outputs a signal for ON / OFF control of terahertz irradiation of the terahertz light source 45 to the light source control unit 36. The light source control unit 36 sets the terahertz irradiation conditions of the terahertz light source 45, and after setting the terahertz irradiation conditions, turns on the terahertz light source 45 via the output unit 37 to irradiate the detection target 63 with terahertz waves. To do.

  The beam adjuster 50 is controlled by the beam controller 38 of the image processing / control device 30. The beam control unit 38 controls the beam adjuster 50 to change the polarization of the terahertz wave from the terahertz light source 45 so as to irradiate the detected object 63 (the concealed object).

  As described above, the image processing / control device 30 can irradiate the terahertz wave to a predetermined spatial position by the beam adjuster 50. Further, when a biaxial gimbal mirror is used as the beam adjuster 50, the horizontal and vertical rotation angles of the biaxial gimbal mirror are controlled, and the terahertz wave from the terahertz light source 45 is moved in the horizontal direction extending in the vertical direction. Irradiation to a predetermined spatial position is possible. Thereby, the terahertz wave from the terahertz light source 45 can be irradiated to the position of the detected object that the subject 60 has.

  An inspected person (detection target) 60 shown in FIG. 1 always has a substantially constant temperature. The detection object 60 is a moving or stationary human, and the human always has a constant body temperature of approximately 37 ° C.

  Note that the substance identification device is not limited to the above-described configuration. For example, the image processing / control device 30 and the control computer 55 may be integrated. Further, a part of the processing of the image processing / control device 30 may be performed by the control computer 55.

  The substance identification device of the present invention having the above-described configuration is included in the detection object 60 from the difference between the signal of the radiant energy radiated from the detection object and the signal of the radiant energy of the detection object 60 around the detection object 63. The detected object 63 is further identified, and the detected object 63 is identified by irradiating the detected object 63 with electromagnetic waves based on the positional information of the detected object 63 included in the detected object 60. To do.

  For this reason, a black body radiation plate having a predetermined temperature as the detection object 60 and a reference sample whose emissivity and reflectance are known are attached to the surface of the black body radiation plate, and the respective radiant energy and reflected energy are obtained. Calibration, which is an update operation for measuring in advance and setting a reference value, is required.

[About calibration]
Hereinafter, calibration of radiant energy and reflected energy relating to the substance identifying apparatus of the present invention will be described with reference to FIG.

  FIG. 4 is a flowchart showing a calibration process of radiant energy and reflected energy related to the substance identifying device.

  In the calibration of the radiant energy related to the substance identification device, first, a black body radiation plate having a predetermined temperature, for example, 37 ° C. which is a human body temperature is installed in the detection area 65 of the terahertz wave, and the temperature is generally controlled. A metal having an emissivity of 0 and a reflectivity of approximately 1 and carbon having an emissivity of approximately 1 and a reflectivity of approximately 0 are attached to the surface of the black body radiation plate as a reference sample (step S1). The surface of the metal as a reference sample has a mirror surface state by gold plating, polishing or the like. The reference sample is not limited to carbon, and may be a substance having an emissivity of approximately 1, such as water or a substance having a resonance band. Furthermore, the material having an emissivity of approximately 0 and a reflectivity of approximately 1 as a reference sample is not limited to a metal, and may be, for example, a substance made of a highly conductive material or a highly doped semiconductor.

  Next, the substance identification device measures the radiant energy of each reference sample and its surroundings (black body radiation plate) (step S2). The difference value is calculated from each measured reference sample and the value of the radiant energy around it (black body radiation plate), and stored as a reference value in the storage device (step S3).

  For example, the reference value of the radiant energy in the metal is the difference between the value of the radiant energy from the metal and the value of the radiant energy of the black body radiating plate around it. This difference is stored in the storage device as the reference value D1 of the radiant energy of the metal.

  Similarly, the reference value of the radiant energy in carbon is the difference between the value of the radiant energy from carbon and the value of the radiant energy of the black body radiating plate around it. This difference is stored in the storage device as the reference value D2 of the radiant energy of carbon.

  Next, the reflection energy calibration process will be described. In the calibration of the reflected energy, the reference sample is set to be irradiated with the terahertz wave of the terahertz light source 45 (step S4). The reference sample used for reflection energy calibration is the same as that used for radiation energy calibration.

  Further, the setting conditions of the terahertz light source 45 such as the irradiation intensity of the terahertz light source 45 and the ON / OFF time interval of the terahertz light source 45 are optimized in consideration of the following. That is, if the reflected energy signal when the terahertz light source 45 is turned on is small, the S / N ratio (signal-to-noise ratio) is deteriorated. Therefore, the irradiation intensity of the terahertz light source 45 is increased to reduce the S / N ratio. prevent. Further, the ON / OFF time interval of the terahertz light source 45 is adjusted so that the terahertz light source 45 is not affected when the terahertz light source 45 is turned off.

  The terahertz light source 45 is turned on to irradiate each reference sample with terahertz waves, and the reflected energy at that time is measured. Further, the terahertz light source 45 is turned off, and the reflected energy of each reference sample is measured (step S5).

  The difference value is calculated from the reflected energy value of each reference sample measured by turning on / off the terahertz light source 45, and stored in the storage device as a reference value (step S6).

  For example, the reference value of the reflected energy in the metal is the difference between the value of the reflected energy from the metal when the terahertz wave of the terahertz light source 45 is irradiated on the metal and the time when the metal is not irradiated. This difference is stored in the storage device as a reference value D3 of the reflected energy of the metal.

  Similarly, the reference value of the reflected energy in carbon is the difference between the value of the reflected energy from the carbon when the terahertz wave of the terahertz light source 45 is irradiated on the carbon and when the carbon is not irradiated. This difference is stored in the storage device as the reference value D4 of the reflected energy of carbon.

  In this way, the reference values of the radiant energy and the reflected energy are calculated and registered in the storage device database. The reference value of the radiant energy and the reflected energy is updated every time calibration is performed.

  The reference values (D1, D3) of the radiant energy and the reflected energy in the metal as the reference sample are set so that the relative value is 1, and the reference values (D2, D4) of the radiant energy and the reflected energy in the carbon as the reference sample. ) Is set so that the relative value becomes zero. Thereby, the relative values of the radiant energy and the reflected energy measured by the detected object 63 are calculated to be in the range of 0 to 1.

  FIG. 5 is a table showing the relative values of radiant energy and reflected energy stored in a database for identifying a substance.

  As shown in FIG. 5A, when the relative value r1 of the radiant energy stored in the database is in the range of 0 to less than 0.2, the detected object (identification material) 63 is identified as powder. When the relative value r1 of the radiant energy stored in the database is in the range of 0.2 to less than 0.6, the detected object (identification material) 63 is identified as paper. Furthermore, when the relative value r1 of the radiant energy stored in the database is in the range from 0.6 to 1, the detected object (identification material) 63 is identified as a metal. In addition, powder means a thing with a particle size below detection wavelength. For example, in this embodiment, since the frequency is 250 GHz, a powder having a particle size of about 1 mm or less is applicable.

  On the other hand, as shown in FIG. 5B, when the relative value r2 of the reflected energy stored in the database is in the range of 0 to less than 0.5, the detected object (identification material) 63 is identified as a non-metal. To do. In addition, when the relative value r2 of the reflected energy stored in the database is in the range of 0.5 to 1, the object to be detected (identification material) 63 is identified as metal.

  Thereby, for example, when the relative value r1 of the radiant energy is 0.55, the detected object (identification material) 63 shows a value close to metal, but is determined to be paper. In this state, when the relative value r2 of the reflected energy is 0.4, the detected object (identification material) 63 is determined to be non-metallic. For this reason, it can be judged that it is paper from the relative value of radiant energy and reflected energy.

  Further, other substance forms such as a liquid, a clay-like object, and a solid substance can be determined by the determination classification in the signal of the terahertz wave radiant energy and the reflected energy. For this reason, the relative value shown in FIG. 5 is an example, and the present invention is not limited to this.

[About substance identification processing]
Next, concealed object detection processing by the substance identification device will be described with reference to FIGS. 1 to 3 and FIG. FIG. 6 is a flowchart showing detection processing of a detection target (concealed object) by the substance identification device.

  The substance identification apparatus according to the present invention automatically recognizes the detection object (inspected person) standing in front of the body scanner of the substance identification apparatus, and automatically inspects the detected object 63 possessed by the inspected person. To start.

  The inspection of the concealed object by the substance identification device is performed by detecting a signal of radiant energy of terahertz waves emitted from the detection object 60 and the detection object 63.

  First, the body scanner detects a terahertz wave radiant energy signal of the person to be inspected (detection target) 60 and performs imaging with the imaging device (CCD camera) 15 (step S10).

  Next, the image processing unit 32 of the image processing / control device 30 cuts out the area of the person to be inspected (detection target) 60 from the image captured by the imaging device (CCD camera) 15 as the detection area 65 (see FIG. 7). The terahertz wave signal and the image of the CCD camera 15 are processed at high speed so that the shape can be recognized, and unnecessary images are eliminated. After eliminating unnecessary images, the radiant energy in the detection area 65 is measured (step S11).

  A threshold is set for the measured radiant energy, and an area of radiant energy equal to or greater than the threshold is detected. The size and shape of the detected area are determined, and an object having an area larger than a predetermined size is defined as a detected object 63. Moreover, the center position in the area detected as the detected object 63 is calculated (step S12).

  With respect to the detected position of the detected object 63, the size of the detected object 63 and the vicinity of the detected object 63 (inspected person 60) with 1.5 to 2 times the dimension of the detected object 63 as a guide. Terahertz wave radiant energy is measured. When measuring the radiant energy of the surrounding terahertz waves, if the surrounding object 63 cannot be surrounded or if the radiant energy of the periphery is not uniform, the measurement range is changed so as to acquire stable radiant energy of the surroundings. To do.

  When the detected object 63 having an area of a predetermined size or larger is detected, the difference processing of the radiant energy signal shown below is performed.

  Difference processing is performed between the signal of the radiant energy radiated by the detected object 63 in the detection area 65 and the signal of the radiant energy of the inspected person (detected object) 60 around the detected object 63 (step S13).

  The determination processing unit 33 calculates the relative value r1 from the difference processing of the radiant energy signal, and identifies (evaluates) the type of the detected object 63 included in the detected object 60 with reference to the database from the calculated relative value r1. (Step S14). The display device 57 displays the image of the detection object 63 included in the detection object 60 detected by the body scanner and the size, shape, and type of the detection object 63 on the image captured by the CCD camera 15. Further, an alarm is issued from the display device 57.

  As a result, the size, shape, and type of the detected object 63 concealed by the human being, which is the detection object 60, are determined.

  The obtained image and the CCD camera 15 image are superposed with their positions aligned in the control computer 55 and displayed on the monitor. FIG. 7 shows an image of a signal of radiant energy and a display example of the display device of the CCD camera 15. The terahertz image, the CCD camera 15 image, and the identification information for each color are superimposed on the left side of the image, and the CCD camera 15 image and the identification information for each color are superimposed on the right side.

  Next, the subject 60 is irradiated with terahertz waves from the terahertz light source 45. Specifically, the terahertz light source 45 irradiates the inspected person 60 at a distance of 3 to 5 m, and the reflected wave (reflected energy signal) from this is similarly detected at a distance of 3 to 5 m in the body scanner 2. 3 is detected, and at the same time, a visible image is captured by the CCD camera 15.

  The distance between the person 60 to be inspected and the terahertz light source 45 and the distance between the person 60 to be inspected and the body scanner 2 are merely examples, and are not limited thereto. The image processing / control device 30 controls the frequency of the terahertz wave irradiated by the terahertz light source 45, the polarization direction of the terahertz wave, the irradiation region, and the like.

  The image processing unit 32 of the image processing / control device 30 controls the beam adjuster 50 from the beam control unit 38 based on the position detection information of the detection target 63 calculated in step S12, and the terahertz wave from the terahertz light source 45 is detected. Is irradiated to the detected object 63 (concealed object) (step S15).

  That is, the position of the detected object 63 is detected by the signal of radiant energy, and the position information of the detected object 63 is input to the beam control unit 38. The beam control unit 38 converts the input position information into rotation angles of the horizontal axis and the vertical axis of the beam adjuster 50, and the center of the terahertz wave of the terahertz light source 45 is irradiated to the position of the detected object 63. To control.

  Thereby, since the terahertz wave is irradiated only to the detected object 63, it is not necessary to irradiate the beam adjuster 50 so that the entire terahertz wave is scanned by the beam adjuster 50. Can be irradiated with terahertz waves.

  The position of irradiation on the detection target 60 from the terahertz light source 45 is determined by the beam control unit 38. Thereafter, the light source controller 36 sets the terahertz irradiation conditions by the terahertz light source 45. Specifically, based on an output chart storing the setting conditions of the terahertz light source 45, an external voltage for controlling the intensity of irradiation of the terahertz wave and its sequence (ON / OFF or terahertz wave output by changing the voltage stepwise) To change).

  After setting the terahertz irradiation conditions, the terahertz light source 45 is turned on via the output unit 37 to irradiate the detection target 63 with terahertz waves (step S16).

  The body scanner 2 measures the reflected energy when the terahertz light source 45 is turned on (step S17).

  Next, the terahertz light source 45 is turned off to stop the irradiation of the terahertz wave (step S18), and the body scanner 2 measures the reflected energy when the terahertz light source 45 is turned off (step S19).

  Difference processing of the reflected energy signal of the detected object 63 when the terahertz light source 45 is turned on / off is performed (step S20).

  The determination processing unit 33 calculates the relative value r2 from the difference processing of the reflected energy signal, and determines the detected object 63 (concealed object) from the calculated relative value r2 with reference to the database shown in FIG. (Evaluation) processing is performed (step S21).

  At this time, the detected image of the detected object 63 (the concealed object) is superimposed on the image of the imaging device, and the image is displayed on the display device 57 (step S22).

  Thus, the detected object 63 (concealed object) can be identified by detecting the radiation energy and reflected energy of the terahertz wave.

[Measurement data of arbitrary values of radiant energy and reflected energy]
Below, an example of the measurement data of the arbitrary values of the radiant energy and reflected energy regarding identification of a to-be-detected object is demonstrated. FIG. 8 is a diagram illustrating an example of measurement data of arbitrary values of radiant energy and reflected energy in an object to be detected. In the measurement, sugar, salt, potato starch and wheat flour as a reference sample powder, paper and aluminum as metal are used on the surface of the black body radiation plate.

  The arbitrary value of the radiant energy shown in FIG. 8 is the intensity difference between the signal of the radiant energy radiated by the detected object and the signal of the radiant energy of the black body radiation plate (detected object) around the detected object. The arbitrary value of the reflected energy is an intensity difference between the reflected energy signal when the object to be detected is irradiated with the terahertz wave and the reflected energy signal when the irradiation of the terahertz wave is turned off.

  As shown in FIG. 8, the arbitrary values of the reflected energy of sugar, salt, potato starch and flour as a powder are about 300 to 800, paper is in the range of 700 to 800, and aluminum as a metal is 1500. To 2000. Moreover, the arbitrary values of the radiant energy of sugar, salt, potato starch and wheat flour as powder are about 0 to 200, paper is around 400, and aluminum as metal is around 900.

  Thereby, although the arbitrary values of the reflected energy between the powder and the paper are overlapped, the arbitrary values of the radiant energy are not overlapped and can be clearly identified.

  In addition, although the data of the arbitrary values of the radiant energy and the reflected energy using the black body radiation plate as the detection target are shown, even when the detection target is a human, the data having the same tendency can be obtained. it can.

  For this reason, the identification of the object to be detected in the substance identification device uses relative values stored on the database shown in FIGS. 5A and 5B, or any value shown in FIG. Try to use it. Moreover, you may use both together.

  In this way, the terahertz wave detection unit in the body scanner receives the signal of the terahertz wave radiant energy from the inspected person, and simultaneously picks up the image of the inspected person with the CCD camera as the imaging device, thereby detecting the terahertz wave. The signal of the radiation energy from the unit and the image of the CCD camera are processed at high speed to recognize the shape, and then the signal of the reflected energy from the substance is processed to identify the substance possessed by the subject.

  As a result, the control computer aligns the image obtained by the terahertz wave detection unit and the image of the CCD camera, and an image obtained by superimposing the image of the terahertz wave detection unit on the image of the CCD camera is displayed on the display device. For this reason, it becomes possible to easily confirm the substance possessed by the subject.

  In addition, if there is identification information based on the difference in intensity of each signal of terahertz wave radiant energy and reflected energy from the object to be detected, if there is something corresponding to an alarm, an alarm sound is generated and the identification information is used for each color. It can be displayed, and anomalies can be notified by sound and images.

  As described above, by detecting the difference between the signal of the radiant energy radiated by the detected object and the signal of the radiant energy of the detected object around the detected object, the detection object included in the detected object is detected. The type can be identified. For example, it is possible to identify that the substance concealed under the person's clothes is powder, paper, or metal.

  In addition, since the position of the object to be detected can be specified by the radiant energy, the signal of the reflected energy from the object to be detected can be reliably obtained by irradiating the electromagnetic wave based on the position specified by the radiant energy. Can do. For this reason, since it is not necessary to irradiate the whole detection target object with electromagnetic waves, the detection target object can be identified in a short time.

  In addition, calibration of terahertz wave radiant energy and reflected energy is performed, and the relative value that is the standard for each substance type is stored in the database, and the type of substance is determined by referring to the database from the measurement results of radiant energy and reflected energy. This makes it possible to identify a stable substance.

[Contrast between prior art documents and the present invention]
Hereinafter, a comparison between the prior art document discovered in the prior art search by the applicant and the present invention will be described. The substance detection and substance identification apparatus disclosed in Patent Documents 1 to 3 relate to a substance identification apparatus having the same technical field as that of the present invention.

  Patent Document 1 (Japanese Patent Laid-Open No. 2005-265793), paragraph number “0009”, lines 8 to 11; Patent Document 2 (Japanese Patent Laid-Open No. 2000-009832), paragraph number “0009”, paragraph number “0010”, and Paragraph No. “0018” in Patent Document 3 (Japanese Patent Laid-Open No. 2005-270568) is irradiated to terahertz light, which is an electromagnetic wave, on the entire detection target (human) from line 1 to line 4, and the reflected energy of the detection target is It is disclosed that a signal is detected and analyzed. However, since these substance detection and identification devices irradiate the entire object to be detected with electromagnetic waves of terahertz light, the detection takes time.

  Further, in Patent Document 1, in order to detect a specific substance, it is necessary to provide an optical filter that transmits only the spectral spectrum of the detected object on the optical path. It was not suitable for.

  Patent Document 4 (Japanese Patent Application Laid-Open No. 2003-294535) receives an electromagnetic wave signal radiated from a measurement site of a human body as disclosed in paragraph “0027”, and further conducts the measurement site. The temperature or the dielectric constant is measured, and the received electromagnetic wave signal is converted into a temperature to measure the temperature at the part of the human body.

  The present invention detects the difference between the signal of the radiant energy radiated by the object to be detected and the signal of the radiant energy of the object to be detected around the object to be detected, thereby determining the type of object to be detected included in the object to be detected. It becomes possible to identify. For example, it is possible to identify that the substance concealed under the person's clothes is powder, paper, or metal.

  In addition, since the position of the object to be detected can be specified by the radiant energy, the signal of the reflected energy from the object to be detected can be reliably obtained by irradiating the electromagnetic wave based on the position specified by the radiant energy. Can do. For this reason, unlike the prior art documents, it is not necessary to irradiate the entire object to be detected with electromagnetic waves, so that the object to be detected can be identified in a short time. For this reason, it is most suitable for the inspection of concealment, dangerous goods, etc. in the place where many passengers use.

  In addition, Patent Document 4 is for receiving an electromagnetic wave signal radiated from a human body, but for measuring a living body temperature at a measurement site of the human body. It does not identify.

  The present invention can be embodied in many forms without departing from its essential characteristics. Therefore, it is needless to say that the above-described embodiment is exclusively for description and does not limit the present invention.

DESCRIPTION OF SYMBOLS 1 Substance identification device 2 Body scanner 3 Terahertz wave detection part 8 Terahertz wave detector 15 Imaging device (CCD camera)
18 Control / Signal Output Unit 20 Scan Mirror 30 Image Processing / Control Device (Image Processing / Control Device)
31 Input unit 32 Image processing unit 33 Discrimination processing unit 36 Light source control unit 37 Output unit 38 Beam control unit 45 Terahertz light source 50 Beam adjuster 55 Control computer 57 Display device 60 Object to be detected (inspected person)
63 Object to be detected (identification material)
65 Detection area

Claims (13)

  In the substance identification device, the signal of the radiant energy of the electromagnetic wave radiated by the detection target including the detection target is measured, and the signal of the radiant energy radiated by the detection target and the detection target around the detection target A substance identification apparatus for identifying a type of the object to be detected included in the object to be detected from a difference from a signal of radiant energy.   In the substance identification device, the detection target is further obtained from a difference between a signal of reflected energy from the detected object when irradiated with electromagnetic waves and a signal of reflected energy from the detected object when not irradiated with electromagnetic waves. The substance identification apparatus according to claim 1, wherein the type of the object to be detected included in the object is identified.   The said substance identification apparatus uses the said signal of at least 1 or more among the signal of the said radiant energy of the electromagnetic wave, or the signal of the said reflected energy regarding the substance identification of the said to-be-detected object. Substance identification device.   The measurement of the radiant energy is performed by measuring a difference between a signal of radiant energy radiated by the detected object and a radiant energy of the detected object having a predetermined temperature around the detected object. The substance identification device according to claim 1 or 3.   The substance identification device according to claim 1, wherein the detection object always has a substantially constant temperature.   6. The substance identification apparatus according to claim 5, wherein the detection target is a moving or stationary human. A material having an emissivity of approximately 0 and a material having an emissivity of approximately 1 are installed as reference samples on the surface of a black body radiation plate having a predetermined temperature, and a signal of the radiant energy of each of the reference samples and the reference sample. Measure the signal of the radiant energy around and calculate each difference value of the radiant energy in each of the reference samples from the difference and store it as a reference value,
The type of the detected object is calculated by calculating a difference value from a difference between a signal of radiant energy radiated by the detected object and a signal of radiant energy of the detected object around the detected object. 5. The substance identification apparatus according to claim 1, wherein a relative value is calculated from the difference value with reference to the reference value of radiant energy. Reflected energy from each of the reference samples when a material having a reflectance of approximately 1 and a material having a reflectance of approximately 0 are set as reference samples on the surface of a black body radiation plate having a predetermined temperature and irradiated with electromagnetic waves. And the signal of the reflected energy from each of the reference samples when the electromagnetic wave is not irradiated, the difference value of the reflected energy in each of the reference samples is calculated from the difference and stored as a reference value,
Identification of the type of the object to be detected is a difference value from a difference between a reflected energy signal reflected by the detected object when irradiated with an electromagnetic wave and a reflected energy signal from the detected object when the electromagnetic wave is not irradiated. The substance identification device according to claim 2, wherein a relative value is calculated from the calculated difference value with reference to the reference value of the reflected energy.   The substance identifying apparatus according to claim 1, wherein the electromagnetic wave is a terahertz wave having a frequency of 10 GHz to 10 THz.   A light source that radiates electromagnetic waves, a beam adjuster that irradiates the object to be detected with electromagnetic waves from the light source, a detection device that detects a signal of radiation energy and / or a signal of reflected energy from the detection object, and The substance identifying apparatus according to claim 2, comprising: an image processing and control apparatus that processes a signal from the detection apparatus.   The position information of the detected object included in the detected object is calculated from the difference between the signal of the radiant energy radiated by the detected object and the signal of the radiant energy of the detected object around the detected object. 3. The substance identification device according to claim 2, wherein the object to be detected is irradiated with electromagnetic waves based on position information.   The imaging means for imaging the detection object, and the difference between the signal of the radiant energy and / or the difference of the signal of the reflected energy in the image of the detection object imaged by the imaging means The substance identifying apparatus according to claim 2, further comprising display means for superimposing and displaying as an image.   The image processing and control device controls the light source, and controls the intensity of electromagnetic wave radiation from the light source based on a signal of radiation energy and / or a signal of reflected energy from the object to be detected. The substance identification device according to claim 10.

Images