JP2013246138A - Portable microwave measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately calibrate thermal noise reception characteristics of receiver elements of a portable microwave measurement device which receives thermal noise in a microwave band radiated from a measurement target and measures the received signal level to detect objects hidden in the measurement target.SOLUTION: A portable microwave measurement device comprises; a handy scanner 2 having a main body 10 which is embedded with a plurality of millimeter wave sensors 12 and a grip portion 20 which is for a user to hold by a hand and manipulate; and a cradle 5 on which the handy scanner 2 is mounted for charging and the like. A mount portion 4 of the cradle 5 for the handy scanner 2 is embedded with a radiowave absorber 8 which faces the millimeter wave sensors 12 when the handy scanner 2 is mounted thereon. Thus, calibrating reception characteristics of each of the millimeter wave sensors 12 while the handy scanner 2 is mounted on the cradle 5 improves object detection accuracy of the handy scanner 2.

Description

  The present invention relates to a portable microwave measurement device that receives thermal noise in a microwave band radiated from a measurement object and measures the reception level.

  Conventionally, thermal noise in the microwave band (0.3 GHz to 3 THz) radiated from a measurement target such as a human body (preferably, thermal noise in the millimeter wave band (30 GHz to 0.3 THz)) is arranged on a straight line. It has been proposed to detect articles (weapons, smuggled goods, etc.) hidden in the measurement object from changes in the reception level of thermal noise received by a plurality of receiving elements (for example, patent documents) 1 and 2).

  Further, in this type of measuring device, the user holds the entire device in his / her hand, and moves (scans) the measuring device in one direction with respect to the measuring object, thereby detecting an object hidden in the measuring object. Has also been proposed (see, for example, Patent Document 1).

Special table 2007-502415 gazette JP 2008-241352 A

  By the way, in order to detect the heat noise of the microwave band radiated | emitted from a measuring object as mentioned above in a receiving element, and to detect the article hidden in the measuring object from the received level, it is output from a receiving element. It is necessary to calibrate the output characteristic (reception characteristic) of the reception signal from the reception element so that the signal level of the reception signal corresponds to the intensity of the thermal noise radiated from the subject.

  Conventionally, when calibrating a receiving element in a portable measuring device, measurement is performed so that the opening surface (receiving direction) of the receiving element faces the floor or wall surface where the amount of radiation of thermal noise is stable. An apparatus is arranged, and the signal level of the received signal is corrected (so-called offset) so that the signal level of the received signal output from the receiving element at that time becomes a predetermined reference level.

  However, when the inventors of the present application measured the detection accuracy of an article by the measuring device after calibrating the receiving element by such a conventional calibration method, the desired accuracy could not be obtained.

  And when this cause was investigated, the thermal noise radiated from the floor or wall surface includes thermal noise radiated from surrounding thermal noise sources, such as thermal noise from lighting equipment (fluorescent lamps, etc.) that illuminates them. It was found that the thermal noise radiated from the floor and wall surface fluctuated.

  The present invention has been made in view of these problems, and receives a thermal noise in a microwave band radiated from a measurement object, and measures the reception level to detect an article hidden in the measurement object. It is an object of the present invention to make it possible to accurately calibrate the reception characteristics of thermal noise by a receiving element in a microwave measuring apparatus.

The portable microwave measuring device according to claim 1, which has been made to achieve the object,
A receiving element for receiving microwaves;
Measuring means for measuring the signal level of the received signal by detecting the received signal from the receiving element;
Correction means for correcting the measurement result by the measurement means;
When a calibration command is input from the outside, a calibration unit that sets a correction amount by the correction unit so that a measurement result obtained through the correction unit becomes a preset reference level;
A measuring device body that is housed in a case that can be hand-held,
A mounting table for mounting the measuring device main body;
With
The mounting table is provided with a facing area that can be opposed to the receiving element when the measuring device main body is placed, and in the facing area, a radio wave having a frequency corresponding to the reception frequency of the receiving element is formed. An electromagnetic wave absorber capable of absorbing is provided.

The invention described in claim 2 is the portable microwave measuring device according to claim 1,
The mounting table is made of a synthetic resin capable of transmitting the microwave, and the radio wave absorber is disposed inside or on the surface of the mounting table.

  According to the portable microwave measuring device of claim 1, the mounting table for mounting the measuring device main body is provided, and when the measuring device main body is mounted on the mounting table, the receiving element An opposing region is formed which can be opposed to each other. And the radio wave absorber which can absorb the electromagnetic wave of the frequency corresponding to the receiving frequency of a receiving element is provided in the opposite field.

  Therefore, according to the portable microwave measuring device of the present invention, when the measuring device main body is calibrated, the measuring device main body is placed on the mounting table so that the receiving element faces the opposing region of the mounting table. Then, a calibration command may be input.

  In other words, in this way, the receiving element provided in the measuring apparatus body receives the microwave radiated from the radio wave absorber, and the measurement result by the measuring means for measuring the signal level of the received signal is the reference level. In this way, the calibration unit sets the correction amount by the correction unit.

  Therefore, the correction amount by the correction means is set to a value corresponding to a certain level of microwave radiated from the radio wave absorber, and calibration of the portable microwave measurement device is performed from the surrounding thermal noise source. It becomes possible to perform optimally without being affected by the radiated thermal noise.

  Here, the mounting table may simply be used for mounting a portable microwave measuring device and calibrating its reception characteristics. For example, a secondary battery built in the portable microwave measuring device. It may be configured as a cradle having a connector connected to the portable microwave measuring device for charging, reading measurement data from the portable microwave measuring device, and the like.

In addition, as described in claim 2, when the mounting table is made of a synthetic resin capable of transmitting microwaves, the radio wave absorber may be disposed inside or on the surface of the mounting table.
Note that the mounting table itself may be configured by a radio wave absorber.

It is a schematic structure figure showing the composition of the whole portable millimeter wave measuring device of an embodiment. It is a block diagram showing the internal structure of the handy scanner of embodiment. It is explanatory drawing explaining the usage method of the handy scanner of embodiment. It is a block diagram showing the structure of the millimeter wave sensor of embodiment. It is a flowchart showing the millimeter wave sensor calibration process performed with the control circuit of embodiment. It is a schematic block diagram showing the modification of a portable millimeter wave measuring device.

Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the portable microwave measuring apparatus according to the present embodiment receives a millimeter-wave band thermal noise radiated from a measurement target, and measures a signal level of the handy scanner 2 and the handy scanner. A cradle 5 for holding the scanner 2 in a mounted state and charging a secondary battery built in the handy scanner 2.

  As shown in FIG. 2, the handy scanner 2 includes a large-diameter main body that houses a plurality of millimeter-wave sensors 12, an operation unit 14, a display unit 16, a control circuit 18, and the like that receive thermal noise in the millimeter-wave band. It is comprised from the part 10 and the holding part 20 in which the secondary battery 22 was accommodated in the inside smaller than the main-body part 10 inside.

  The main body 10 and the grip 20 of the handy scanner 2 are configured by housing each of the above parts in a case made of a synthetic resin having a hollow cylindrical shape and a step in the central axis direction. Are arranged at substantially equal intervals on a straight line parallel to the central axis of the case in the case constituting the main body 10.

Further, in the handy scanner 2, the handy scanner 2 is placed on the cradle 5 at the end opposite to the main body 10 (the rear end side of the handy scanner 2) of the gripping unit 20. A connection terminal 24 connected to the provided connector part 6 for charging is provided.
The connection terminal 24 is connected to the secondary battery 22 and to the control circuit 18 in the main body 10.

Next, the control circuit 18 is constituted by a microcomputer including a CPU, a ROM, a RAM, an A / D converter, and the like.
Then, in accordance with a command input from the operation unit 14, the control circuit 18 takes in a detection signal indicating a reception level of millimeter waves from the plurality of millimeter wave sensors 12, and the inspection subject who is a subject is determined from the change in the detection signals. A hidden dangerous object (knife, handgun, etc.) is detected, and a dangerous substance detection process to notify the surroundings and a calibration process to calibrate the reception characteristics of each millimeter wave sensor 12 are executed.

  The operation unit 14 includes a switch for inputting a millimeter wave measurement command (in other words, a dangerous substance detection command) or a calibration command for the millimeter wave sensor 12 when the user operates with a finger. The main body 10 is arranged in the vicinity of the grip 20 so that the user can operate it while holding the grip 20.

  The display unit 16 is for displaying the operating state of the handy scanner 2 and displaying the detection result of the dangerous substance described above, and is composed of an LED, a liquid crystal display panel, and the like. And the display part is arrange | positioned on the opposite side (the front end side of the handy scanner 2) of the operation part 14 with respect to the holding part 20 side so that a user may see display content easily.

  In the handy scanner 2 of the present embodiment configured as described above, when a measurement command is input via the operation unit 14, the control circuit 18 takes in the detection signals from the plurality of millimeter wave sensors 12, and the detection signals From the change, the dangerous object concealed by the person to be inspected is detected.

This is because thermal noise in the millimeter wave band is radiated from the subject to be inspected, and if the subject to be inspected conceals the dangerous object, the thermal noise is shielded by the dangerous object.
That is, in the handy scanner 2 of the present embodiment, as shown in FIG. 3, the user grips the grip part 20 and directs the reception surface of the main body part 10 by the millimeter wave sensor 12 toward the subject to be inspected. If the movement is made in a direction perpendicular to the arrangement direction, the signal level of the received signal from the millimeter wave sensor 12 located at a position facing the dangerous object concealed by the subject to be examined is lowered during the movement.

  Therefore, in the present embodiment, it is possible to automatically detect that the person to be inspected is hiding a dangerous object from the change (decrease) in the signal level that occurs when the user operates the handy scanner 2 in this way. It is.

  By the way, when detecting a dangerous object using the handy scanner 2 in this way, in order to increase the detection accuracy of the dangerous object, when the thermal noise of the millimeter wave band radiated from the inspection subject is received, It is necessary to set the reception characteristics of the millimeter wave sensor 12 so that the signal level of the detection signal changes greatly when the thermal noise is interrupted.

Since the reception characteristics of the millimeter wave sensor 12 change depending on the usage environment such as the ambient temperature, it is desirable to periodically calibrate the handy scanner 2 when it is used.
Therefore, in the present embodiment, the millimeter wave sensor 12 can correct (calibrate) the reception characteristics of the thermal noise in the millimeter wave band.

  That is, as shown in FIG. 4, the millimeter wave sensor 12 of the present embodiment includes an antenna 30 as a receiving element that receives thermal noise in the millimeter wave band, and a reception signal (high frequency signal: RF) from the antenna 30. An RF amplifier 32 for amplifying the signal, a detection circuit 34 for amplitude detection of the reception signal amplified by the RF amplifier 32, and a correction signal (voltage) to be added to the detection signal (voltage) detected by the detection circuit 34 Thus, the addition circuit 36 for correcting the detection signal and the detection signal (voltage) representing the signal level of the millimeter-wave band thermal noise received by the antenna 30 by amplifying the detection signal corrected by the addition circuit 36. And a direct current amplifier circuit 38 for outputting

The detection signal output from the DC amplification circuit 38 is input to the control circuit 18, and the correction signal output from the control circuit 18 is input to the addition circuit 36.
This correction signal is set for each millimeter wave sensor 12 by the control circuit 18 executing the millimeter wave sensor calibration process shown in FIG. 5, and the control circuit 18 executes the dangerous substance detection process. In the middle, by outputting a correction signal to each millimeter wave sensor 12, the reception characteristic of each millimeter wave sensor 12 is corrected, and the detection accuracy of dangerous substances is ensured.

Then, next, millimeter wave sensor calibration processing will be described along the flowchart shown in FIG.
The millimeter wave sensor calibration process shown in FIG. 5 is a process executed when a calibration command for the millimeter wave sensor 12 is input via the operation unit 14, and when the process is started, first, S110 (S is a step). The initial value (value 1) is set to the counter C used in the subsequent processing.

  Next, in S120, the signal level of the detection signal (hereinafter referred to as the detection signal level) is read from the C-th millimeter wave sensor corresponding to the value of the counter C among the plurality of millimeter wave sensors 12.

  In subsequent S130, the signal level of the correction signal (hereinafter referred to as the correction signal level) output to the addition circuit 36 of the millimeter wave sensor 12 so that the detection signal level becomes a preset reference level (zero in the present embodiment). In step S140, the set correction signal level is stored in the RAM or nonvolatile memory as the correction signal level of the C-th millimeter wave sensor 12.

  Next, in S150, it is determined whether or not the value of the counter C is greater than or equal to a value n representing the number of millimeter wave sensors 12 provided in the main body unit 10, and the value of the counter C must be greater than or equal to the value n. For example, after incrementing (+1) the value of the counter C in S160, the process proceeds to S120 again. If the value of the counter C is equal to or greater than the value n, it is determined that the calibration processing for all the millimeter wave sensors 12 has been completed. Then, the millimeter wave sensor calibration process ends.

  As described above, the handy scanner 2 of the present embodiment is provided with a function of automatically calibrating the reception characteristics of the millimeter wave sensor 12. At the time of this calibration, a millimeter wave signal input to each millimeter wave sensor 12 is provided. The level needs to be small enough and constant.

  For this reason, conventionally, such a calibration operation is performed so that the millimeter wave sensor 12 is directed toward the floor surface or the wall surface, but this is affected by the millimeter wave reflected from the floor surface or the wall surface, The millimeter wave sensor 12 could not be accurately calibrated.

  Therefore, in the present embodiment, as shown in FIG. 1, the handy scanner 2 is placed on the cradle 5 with the side surface on which each millimeter wave sensor 12 (specifically, the antenna 30) is disposed downward facing the handy scanner 2. A mounting portion 4 for mounting is provided, and a plate-shaped radio wave absorber 8 is disposed at a position facing each millimeter wave sensor 12 in the mounting portion 4.

  That is, in the present embodiment, with the mounting portion 4 of the cradle 5 placed on the millimeter wave sensor 12 side surface of the main body 10 of the handy scanner 2 so as to face each other, the rear end of the gripping portion 20 of the handy scanner 2 is placed. The cradle 5 is configured with a case made of synthetic resin and having an L shape so that the provided connection terminal 24 can be connected to the connector portion 6 of the cradle 5, and the radio wave absorber 8 is disposed therein. Thus, the handy scanner 2 can be calibrated with the antenna 30 of each millimeter wave sensor 12 facing the radio wave absorber 8.

  Therefore, according to the portable microwave measuring apparatus of the present embodiment, the handy scanner 2 is placed on the cradle 5 when the reception characteristics of the plurality of millimeter wave sensors 12 provided in the handy scanner 2 are calibrated. Thus, the reception characteristics of each millimeter wave sensor 12 can be calibrated with the millimeter wave incident on each millimeter wave sensor 12 being constant, and the calibration is radiated from the surrounding thermal noise generation sources. It is possible to carry out the optimum implementation without being affected by the thermal noise.

  The radio wave absorber 8 includes a conductive radio wave absorber material composed of conductive fibers, a dielectric radio wave absorber material in which a dielectric loss is increased by mixing carbon powder or the like with a dielectric material such as rubber or urethane foam, Various conventionally known radio wave absorbing materials such as a magnetic radio wave absorbing material that absorbs radio waves by magnetic loss of a magnetic material such as iron, nickel, and ferrite can be used.

  Moreover, as a general thing of a radio wave absorber, what has ferrite, rubber ferrite, urethane, carbon, etc. as a main component is known, but since a radio wave can be absorbed also with water, A solution in which an aqueous solution is filled in a synthetic resin bag can also be used.

  Here, in the present embodiment, the handy scanner 2 corresponds to the measuring apparatus main body of the present invention, and the cradle 5 corresponds to the mounting table of the present invention. The antenna 30 constituting the millimeter wave sensor 12 corresponds to the receiving element of the present invention, the detection circuit 34 corresponds to the measuring means of the present invention, and the adding circuit 36 corresponds to the correcting means of the present invention. The control circuit 18 corresponds to the calibration means of the present invention.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various aspect can be taken in the range which does not deviate from the summary of this invention.
For example, in the above-described embodiment, the radio wave absorber 8 is described as being housed in the case constituting the placement unit 4 of the cradle 5, but as illustrated in FIG. 6, the surface of the placement unit 4 of the cradle 5. (In other words, it may be provided on the mounting surface of the handy scanner 2).

  In the above embodiment, the radio wave absorber 8 is provided in the cradle 5 for charging the handy scanner 2 so that the millimeter wave sensor 12 can be properly calibrated. Even if a calibration mounting table including the radio wave absorber 8 is provided, the same effect as in the above embodiment can be obtained.

  In this case, unlike the cradle 5, the mounting table does not need to be provided with a signal line (not shown) for connecting the connector unit 6 and the connector unit 6 to an external device such as a charger. It may be configured by a radio wave absorber.

  In the above-described embodiment, the handy scanner 2 as the measuring apparatus main body has a plurality of millimeter wave sensors 12 arranged in a straight line along the side wall thereof, and the handy scanner 2 includes the plurality of millimeter wave sensors. 12 has been described as functioning as a so-called line sensor.

  However, according to the present invention, one handy millimeter wave sensor 12 is provided in the handy scanner as the main body of the measuring device, and the user adjusts the direction of the handy scanner 2 so that the thermal noise caused by the millimeter wave sensor 12 is adjusted. Even if it is configured to manually adjust the measurement position, it can be applied in the same manner as in the above embodiment to obtain the same effect.

  Furthermore, in the above-described embodiment, the millimeter wave sensor 12 has been described as receiving the thermal noise of the millimeter wave band radiated from the subject to be inspected. Noise may be received.

  DESCRIPTION OF SYMBOLS 2 ... Handy scanner, 4 ... Mounting part, 5 ... Cradle, 6 ... Connector part, 8 ... Radio wave absorber, 10 ... Main part, 12 ... Millimeter wave sensor, 14 ... Operation part, 16 ... Display part, 18 ... Control Circuit: 20 ... Grasping part, 22 ... Secondary battery, 24 ... Connection terminal, 30 ... Antenna, 32 ... RF amplifier, 34 ... Detection circuit, 36 ... Addition circuit, 38 ... DC amplification circuit.

Claims (2)

A receiving element for receiving microwaves;
Measuring means for measuring the signal level of the received signal by detecting the received signal from the receiving element;
Correction means for correcting the measurement result by the measurement means;
When a calibration command is input from the outside, a calibration unit that sets a correction amount by the correction unit so that a measurement result obtained through the correction unit becomes a preset reference level;
A measuring device body that is housed in a case that can be hand-held,
A mounting table for mounting the measuring device main body;
With
The mounting table is provided with a facing area that can be opposed to the receiving element when the measuring device main body is placed, and in the facing area, a radio wave having a frequency corresponding to the reception frequency of the receiving element is formed. A portable microwave measuring device provided with an absorbable radio wave absorber.   2. The portable type according to claim 1, wherein the mounting table is made of a synthetic resin capable of transmitting the microwave, and the radio wave absorber is disposed inside or on the surface of the mounting table. Microwave measuring device.

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