Abnormality monitoring system, abnormality monitoring method and program

Abstract

This abnormality-monitoring system (80) is a system for monitoring abnormalities in an electromagnetic field spatial distribution measurement system (10) provided with a reference signal generator (second EO probe (22), etc.) for generating a reference signal, a measurement probe (first EO probe (21), etc.) for detecting an electrical field while scanning a measurement point in an electromagnetic field having a given relationship with the reference signal, and a signal-processing unit (signal-processing unit (30), etc.) for calculating the amplitude and the phase of the electrical field indicated by a measurement signal outputted by the measurement probe and outputting the calculated amplitude and phase as measurement results, the abnormality-monitoring system comprising a distributor (50), etc., for distributing the reference signal, and a monitoring unit (62) for determining the presence / absence of an abnormality in the electromagnetic field spatial distribution measurement system (10) on the basis of the reference signal distributed by the distributor (50), etc.

Description

[Technical Field]

[0001] The present disclosure relates to an abnormality monitoring system, an abnormality monitoring method, and a program, and in particular to a system for monitoring an abnormality in an electromagnetic field space distribution measuring system. [Background technology]

[0002] As an application example of an electromagnetic field spatial distribution measurement system that measures the spatial distribution of an electromagnetic field caused by electromagnetic waves radiated from an antenna, an imaging device that visualizes the inside of an object nondestructively has been proposed (see Patent Document 1).

[0003] The imaging device of Patent Document 1 is a device that measures the amount of phase shift of electromagnetic waves, such as millimeter waves, when they pass through or reflect off an object, and creates an image. It includes a first probe and a second probe that are arranged in space to measure the electric field, a reference signal generator that generates a reference signal, a first multiplier that multiplies the signal obtained by the first probe by the reference signal, a second multiplier that multiplies the signal output from the first multiplier by the signal obtained by the second probe, and a synchronous detector that extracts a signal component that is synchronized with the reference signal from the signal output from the second multiplier. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 026494 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology of Patent Document 1 does not have a function to detect abnormalities when they occur in the imaging device, so measurements may be taken without noticing the abnormality, rendering the measurement results unusable, or in the worst case, the validity of the results cannot be determined, so the measurement results may be processed without being determined to be abnormal (for example, a GO / NO decision may be made incorrectly, or the results may be over- or underestimated).In particular, with an electromagnetic field spatial distribution measurement system that handles high-frequency signals, it is not easy to determine just by looking at the measurement results whether they were obtained as a result of normal operation of the device.

[0006] Therefore, an object of the present disclosure is to provide an abnormality monitoring system, an abnormality monitoring method, and a program that can monitor abnormalities in an electromagnetic field space distribution measuring system. [Means for solving the problem]

[0007] In order to achieve the above object, an anomaly monitoring system according to one embodiment of the present disclosure is an anomaly monitoring system that monitors an anomaly in an electromagnetic field spatial distribution measurement system, the electromagnetic field spatial distribution measurement system comprising: a reference signal generator that generates a reference signal; a measurement probe that detects an electric field while scanning a measurement point in an electromagnetic field that has a certain relationship with the reference signal; and a signal processing unit that calculates the amplitude and phase of the electric field indicated by the measurement signal output from the measurement probe and outputs the calculated amplitude and phase as measurement results, and the anomaly monitoring system comprises: a distributor that distributes the reference signal; and a monitoring unit that determines whether or not there is an anomaly in the electromagnetic field spatial distribution measurement system based on the reference signal distributed by the distributor.

[0008] In order to achieve the above object, an abnormality monitoring method according to one embodiment of the present disclosure is an abnormality monitoring method using an abnormality monitoring system that monitors abnormalities in an electromagnetic field spatial distribution measurement system, wherein the electromagnetic field spatial distribution measurement system comprises a reference signal generator that generates a reference signal, a measurement probe that detects an electric field while scanning a measurement point in an electromagnetic field that has a certain relationship with the reference signal, and a signal processing unit that calculates the amplitude and phase of the electric field indicated by the measurement signal output from the measurement probe and outputs the calculated amplitude and phase as measurement results, and the abnormality monitoring method includes a distribution step that distributes the reference signal, and a monitoring step that determines whether or not there is an abnormality in the electromagnetic field spatial distribution measurement system based on the distributed reference signal.

[0009] In order to achieve the above object, a program according to one embodiment of the present disclosure is a program for monitoring an abnormality in an electromagnetic field space distribution measuring system, and causes a computer to execute the above monitoring step. [Effects of the Invention]

[0010] The present disclosure provides an abnormality monitoring system, an abnormality monitoring method, and a program that can monitor an abnormality in an electromagnetic field space distribution measuring system. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing the configuration of an electromagnetic field space distribution measuring system including an anomaly monitoring system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an external appearance and an example of operation of the electromagnetic field space distribution measuring system according to the embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of a display on the display unit when an abnormality occurs in the electromagnetic field space distribution measuring system according to the embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of criteria for determining an abnormality by the monitoring unit included in the electromagnetic field space distribution measuring system according to the embodiment. [Figure 5]FIG. 5 is a flowchart showing the operation of the electromagnetic field space distribution measuring system according to the embodiment in the first operation mode. [Figure 6] FIG. 6 is a flowchart showing the operation of the electromagnetic field space distribution measuring system according to the embodiment in the second operation mode. [Figure 7] FIG. 7 is a block diagram showing the configuration of an electromagnetic field space distribution measuring system including an anomaly monitoring system according to a first modified example of the embodiment. [Figure 8] FIG. 8 is a block diagram showing the configuration of an electromagnetic field space distribution measuring system including an anomaly monitoring system according to a second modified example of the embodiment. [Figure 9] FIG. 9 is a block diagram showing the configuration of an electromagnetic field space distribution measuring system including an anomaly monitoring system according to a third modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that each embodiment described below represents a specific example of the present disclosure. The numerical values, shapes, materials, components, component arrangement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, each figure is not necessarily an exact illustration. In each figure, substantially identical configurations are assigned the same reference numerals, and redundant explanations are omitted or simplified. Furthermore, "A and B are connected" means that A and B are electrically connected, and includes not only the case where A and B are directly connected, but also the case where A and B are indirectly connected with another circuit element interposed between A and B.

[0013] 1 is a block diagram showing the configuration of an electromagnetic field space distribution measuring system 10 according to an embodiment, which includes an anomaly monitoring system 80. The electromagnetic field space distribution measuring system 10 is an imaging device that measures the spatial distribution of an electromagnetic field due to electromagnetic waves (RF signals) radiated from an antenna 15, and includes an EO type detection unit 20, a signal processing unit 30, a controller 60, an input unit 70, and a display unit 71.

[0014] The EO type detection unit 20 is a processing unit that detects the electromagnetic field to be measured using two probes and outputs two electrical signals of intermediate frequencies, and is composed of a sweep device 40, a first EO (electro-optical) probe 21, a second EO (electro-optical) probe 22, a first optical circulator 23, a second optical circulator 24, a first optical filter 25, a second optical filter 26, a first optical detector 27, and a second optical detector 28.

[0015] The first EO probe 21 is a measurement probe that is fixed to a sweeping device 40 such as an XY stage and detects an electric field while scanning a measurement point in the electromagnetic field to be measured. The first optical circulator 23 outputs an optical LO signal input from the outside to the first EO probe 21 and converts the electric field signal (frequency f RF The first optical circulator 23 outputs an optical signal of a plurality of frequency components generated by the interaction between the optical signal of the plurality of frequency components (optical signal of frequency f) and the optical LO signal to the first optical filter 25. The first optical filter 25 passes only the optical signal of a specific frequency band among the optical signals of the plurality of frequency components input from the first optical circulator 23, and outputs the passed optical signal to the first optical detector 27. The first optical detector 27 detects the optical signal input from the first optical filter 25 as a signal of frequency f IF The signal is converted into an electrical signal (first IF (intermediate) signal) and output as a measurement signal.

[0016] The second EO probe 22 is a reference probe that detects an electric field in a fixed state in the electromagnetic field to be measured. The second optical circulator 24 outputs an optical LO signal input from the outside to the second EO probe 22 and converts the electric field signal (frequency f RFThe optical signals of a plurality of frequency components generated by the interaction between the optical signal) and the optical LO signal are output to the second optical filter 26. The second optical filter 26 passes only the optical signals in a specific frequency band among the optical signals of a plurality of frequency components input from the second optical circulator 24 and outputs them to the second photodetector 28. The second photodetector 28 converts the optical signal input from the second optical filter 26 into an electrical signal (second IF (intermediate) signal) of frequency f IF and outputs it as a reference signal.

[0017] The first optical circulator 23, the first optical filter 25, and the first photodetector 27 correspond to a first frequency converter that converts the optical signal output from the first EO probe 21 into an electrical signal (measurement signal) of an intermediate frequency lower than the frequency of the optical signal. Similarly, the second optical circulator 24, the second optical filter 26, and the second photodetector 28 correspond to a second frequency converter that converts the optical signal output from the second EO probe 22 into an electrical signal (reference signal) of an intermediate frequency lower than the frequency of the optical signal. Also, the second EO probe 22 can be said to be a reference signal generator that generates a reference signal. In that case, the measurement probe that detects the electric field while scanning the measurement point in an electromagnetic field having a certain relationship with the reference signal corresponds to the first EO probe 21.

[0018] The signal processing unit 30 is a processing unit that performs signal processing for canceling the phase and frequency fluctuations of the electric field in the measured electromagnetic field, and is composed of a reference signal generator 31, a first multiplier 32, a filter 33, a second multiplier 34, a synchronous detector 35, and a distributor 50.

[0019] The distributor 50 distributes the second IF signal (frequency f IF ) which is the reference signal output from the second photodetector 28 with a branching ratio of n:m (m < n), outputs the electrical signal corresponding to m of the distributed signals to the first multiplier 32, and outputs the optical signal corresponding to n of the distributed signals to the measurement control unit 61 of the controller 60.

[0020] The reference signal generator 31 is a circuit that generates a reference signal used to cancel the above-mentioned phase and frequency fluctuations, and generates, for example, a signal of a single frequency fs. The first multiplier 32 multiplies the second IF signal (frequency fs) output from the second photodetector 28 via the distributor 50. IF ) by the reference signal (frequency fs) generated by the reference signal generator 31, the frequency (fs+f IF ) and frequency (fs-f IF The filter 33 outputs a signal containing a signal component having the frequency (fs+f IF ) and frequency (fs-f IF ) from a signal containing a signal component with frequency (fs-f IF ) and bandpass filters that select signal components with

[0021] The second multiplier 34 multiplies the signal (frequency (fs-f IF )) is the first IF signal (frequency f IF ) to obtain the frequency fs (=fs-f IF +f IF ) and frequency (fs-2f IF ) and outputs a signal containing a signal component with the

[0022] The synchronous detector 35 is a lock-in amplifier that receives the signal output from the second multiplier 34, extracts only the signal component that is synchronized with the reference signal generated by the reference signal generator 31, and outputs the signal to the measurement control section 61 of the controller 60. The detection signal output from the synchronous detector 35 indicates the amplitude and phase of the electric field to be measured at the measurement point where the first EO probe 21 is placed (the phase is based on the phase of the electric field to be measured at the reference point where the second EO probe 22 is placed in the electric field to be measured). In this way, the synchronous detector 35 extracts the signal output from the second multiplier 34 at the frequency fs (=f) of the reference signal, in which the phase and frequency fluctuations of the electric field to be measured are canceled and the signal component dependent on the intermediate frequency is canceled. s -f IF +f IF) is extracted and the amplitude and phase of the electric field to be measured are identified.

[0023] The controller 60 is an integrated system having a measurement control unit 61 that controls the electromagnetic field space distribution measurement system 10 and performs measurements using the electromagnetic field space distribution measurement system 10, and a monitoring unit 62 that determines whether or not there are any abnormalities in the electromagnetic field space distribution measurement system 10, and is realized by a computer device connected to a display unit 71 such as a display and an input unit 70 such as a mouse.

[0024] The measurement control unit 61 is connected to each component of the electromagnetic field space distribution measurement system 10 and controls the execution of measurements by the electromagnetic field space distribution measurement system 10 while communicating with each component of the electromagnetic field space distribution measurement system 10. For example, the measurement control unit 61 controls the sweep device 40 to cause the first EO probe 21 to scan measurement points in the electromagnetic field to be measured, while acquiring measurement results (the amplitude and phase of the electric field indicated by the measurement signal with respect to the reference signal) output from the synchronous detector 35, thereby visualizing at least one of the amplitude and phase for each measurement point and displaying the obtained image on the display unit 71. The measurement control unit 61 is composed of an input / output interface circuit for connecting to the sweep device 40 and the synchronous detector 35, a memory for storing programs, etc., a processor for executing the programs, etc.

[0025] The monitoring unit 62 is a processing unit that determines whether or not there is an abnormality in the electromagnetic field space distribution measuring system 10 based on the reference signal distributed by the distributor 50, and is composed of a frequency analyzer 62a that analyzes the reference signal output from the distributor 50, an interface circuit that connects to the frequency analyzer 62a, a memory that stores programs and the like, a processor that executes programs, etc. The monitoring unit 62 has the following characteristic functions.

[0026] That is, the monitoring unit 62 includes a notification unit (here, the display unit 71) that notifies the user of the abnormality when it determines that there is an abnormality in the electromagnetic field space distribution measurement system 10. Furthermore, when it determines that there is an abnormality in the electromagnetic field space distribution measurement system 10, the monitoring unit 62 invalidates the measurement result output by the measurement control unit 61. Furthermore, the monitoring unit 62 determines whether there is an abnormality in the electromagnetic field space distribution measurement system 10 before scanning by the measurement probe (first EO probe 21) is started, and when it determines that there is an abnormality in the electromagnetic field space distribution measurement system 10, it performs control to prevent scanning by the measurement probe (first EO probe 21) from starting.

[0027] The distributor 50 , the monitoring unit 62 and the display unit 71 constitute an abnormality monitoring system 80 that monitors the electromagnetic field space distribution measuring system 11 for abnormalities.

[0028] FIG. 2 illustrates an external view and an example of operation of an electromagnetic field space distribution measurement system 10 according to an embodiment. More specifically, (a) of FIG. 2 illustrates the external view of the electromagnetic field space distribution measurement system 10, (b) of FIG. 2 illustrates an example of a spatial distribution display of the amplitude of the electric field on an XY plane orthogonal to the radiation direction of the electromagnetic wave in the electromagnetic field to be measured, visualized by the measurement control unit 61 of the electromagnetic field space distribution measurement system 10, (c) of FIG. 2 illustrates an example of a spatial distribution display of the phase of the electric field on an XY plane orthogonal to the radiation direction of the electromagnetic wave in the electromagnetic field to be measured, visualized by the measurement control unit 61 of the electromagnetic field space distribution measurement system 10, and (d1) and (d2) of FIG. 2 illustrate examples of the directional characteristics of the electromagnetic wave radiated from the antenna 15, visualized by the measurement control unit 61 of the electromagnetic field space distribution measurement system 10. (d1) and (d2) of FIG. 2 respectively illustrate the directional characteristics of the electromagnetic wave radiated from the antenna 15 on the electric field plane and the magnetic field plane. In these examples, the frequency of the electromagnetic wave radiated from the antenna 15 is 77 GHz. The display examples shown in (b) and (c) of FIG. 2 are actually displayed on the display unit 71 as color images.

[0029] Fig. 3 is a diagram illustrating an example of a display by the display unit 71 when there is an abnormality in the electromagnetic field space distribution measurement system 10 according to the embodiment. More specifically, (a) of Fig. 3 shows an example of a display of the spatial distribution of the amplitude of the electric field on a plane along the radiation direction (Z-axis) of the electromagnetic wave in the measured electromagnetic field when there is an abnormality in the electromagnetic field space distribution measurement system 10, and (b) of Fig. 3 shows an example of a display when there is no abnormality in the electromagnetic field space distribution measurement system 10.

[0030] 3(a), unlike FIG. 3(b), which shows a continuous change in the measurement result value, the measurement result (amplitude) changes suddenly at the boundary between the upper and lower halves, which is unnatural and suggests that an abnormality has occurred in the measurement by the electromagnetic field space distribution measurement system 10. However, in many cases, the image in which the measurement result is visualized shows an unknown measurement result, and it is not easy to determine whether the result is a normal measurement by the electromagnetic field space distribution measurement system 10 or whether an abnormality has occurred in the measurement. Therefore, the electromagnetic field space distribution measurement system 10 according to this embodiment is provided with an abnormality monitoring system 80 (i.e., a distributor 50, a monitoring unit 62, and a display unit 71) that determines whether an abnormality has occurred in the electromagnetic field space distribution measurement system 10.

[0031] 4 is a diagram illustrating an example of criteria for determining an abnormality by the monitoring unit 62 included in the electromagnetic field space distribution measuring system 10 according to the embodiment. An example of a display of the frequency analyzer 62a included in the monitoring unit 62 is shown here.

[0032] As shown in the figure, the frequency analyzer 62a generates the spectrum of the reference signal distributed by the distributor 50. The monitoring unit 62 acquires the spectrum obtained by the frequency analyzer 62a and determines that there is an abnormality in the electromagnetic field space distribution measuring system 10 if (1) the frequency of a peak in the acquired spectrum is not within a predetermined frequency range, or (2) at least one of the signal-to-noise ratio and signal strength of the peak does not reach a threshold. For example, as shown in the figure, the monitoring unit 62 determines that there is an abnormality in the electromagnetic field space distribution measuring system 10 if the peak of the second IF signal is not within a frequency range of 1.8 MHz ± 0.1 MHz, or if the S / N is not 40 dB or more.

[0033] Next, the operation of the electromagnetic field space distribution measuring system 10 (particularly the anomaly monitoring system 80 provided in the electromagnetic field space distribution measuring system 10) according to this embodiment configured as described above will be described. The electromagnetic field space distribution measuring system 10 operates in two operation modes that can be selected by user instructions entered via the input unit 70. The first operation mode is an anomaly monitoring method that does not stop measurement even if an abnormality is found before or during measurement, and notifies the user whether the final result is good or bad. The second operation mode is an anomaly monitoring method that does not start measurement if an abnormality is found before measurement (however, measurement is not stopped midway even if an abnormality occurs after measurement has started).

[0034] FIG. 5 is a flowchart showing the operation of the electromagnetic field space distribution measuring system 10 according to the embodiment in the first operation mode.

[0035] When the measurement starts, the measurement control unit 61 controls the sweep equipment 40 to move the measurement probe (first EO probe 21) to the next measurement point in the electromagnetic field to be measured (S10), and then obtains the measurement results (amplitude and phase) at that measurement point from the synchronous detector 35 (S11) and stores them in association with the position of the measurement point.

[0036] Next, the monitoring unit 62 performs an abnormality diagnosis (S12). Specifically, the monitoring unit 62 receives the reference signal (second IF signal) output from the distributor 50 as input, acquires from the frequency analyzer 62a a spectrum obtained by the frequency analyzer 62a, and determines whether (1) the frequency of the peak of the reference signal is within a predetermined frequency range, and (2) both the signal-to-noise ratio and the signal strength of the peak of the reference signal reach thresholds.

[0037] As a result, if an abnormality has occurred (No in S12), that is, if (1) the frequency of the peak of the reference signal is not within a predetermined frequency range, or (2) at least one of the signal-to-noise ratio and signal strength of the peak of the reference signal does not reach a threshold, the monitoring unit 62 determines that an abnormality has occurred in the electromagnetic field space distribution measuring system 10, and displays "abnormality present" on the display unit 71 (S13). Note that the display of "abnormality present" (S13) may also display the position of the current measurement point and the details of the abnormality (peak frequency / SN ratio / signal strength), and in addition, a flag indicating that an abnormality has occurred and the details of the abnormality may be stored together with the measurement result, in association with the position of the current measurement point.

[0038] On the other hand, if no abnormality has occurred (Yes in S12) and after step S13, the measurement control unit 61 determines whether all measurements (sweeps) have been completed by determining whether the current measurement point is the final position (S14). If it is determined that all measurements (sweeps) have not been completed (No in S14), the measurement control unit 61 repeats steps S10 to S14.

[0039] On the other hand, if the measurement control unit 61 determines that all measurements (sweeps) have been completed (Yes in S14), the monitoring unit 62 determines whether any abnormality has occurred during the measurements (S15).

[0040] As a result, if it is determined that an abnormality has occurred at least once during the measurement (No in S15), the monitoring unit 62 assigns a flag to the series of measurement results obtained, indicating that the results are "reference results" (S16). The flag indicating that the results are "reference results" indicates that the measurement results are not valid, and is an example of information for invalidating the measurement results.

[0041] In step S15, if the measurement control unit 61 determines that no abnormality has occurred during the measurement (Yes in S15), and after step S16, the measurement control unit 61 and monitoring unit 62 end the processing.

[0042] In this way, in the first operating mode, even if there is an abnormality before or during the measurement, the measurement is carried out to the end without being stopped, and when an abnormality occurs, this is displayed in real time on the display unit 71, and a flag indicating that the series of measurement results obtained are "reference results" is assigned, making it possible to refer to the measurement results after recognizing that they are measurement results obtained in a situation where an abnormality occurred (i.e., invalid measurement results).

[0043] In the flowchart of FIG. 5, the process starts from step S10 in which the measurement probe (first EO probe 21) is moved to the next measurement point in the electromagnetic field to be measured. However, prior to this, the monitoring unit 62 may perform an abnormality diagnosis before the measurement starts.

[0044] FIG. 6 is a flowchart showing the operation of the electromagnetic field space distribution measuring system 10 according to the embodiment in the second operation mode.

[0045] When the electromagnetic field space distribution measurement system 10 is started up, first the measurement control unit 61 initializes the electromagnetic field space distribution measurement system 10 (S20). Here, initialization of the electromagnetic field space distribution measurement system 10 means adjustment and setup of each component of the electromagnetic field space distribution measurement system 10, and specifically includes the measurement control unit 61 sending an initialization command or a command to set each component of the electromagnetic field space distribution measurement system 10 to an initial state, or conveying a message to the user via the display unit 71 to prompt the user to adjust and setup each component of the electromagnetic field space distribution measurement system 10.

[0046] Next, the monitoring unit 62 performs an abnormality diagnosis (S21). Specifically, the monitoring unit 62 receives the reference signal (second IF signal) output from the distributor 50 as an input, acquires from the frequency analyzer 62a a spectrum obtained by the frequency analyzer 62a, and determines whether (1) the frequency of the peak of the reference signal is within a predetermined frequency range, and (2) both the signal-to-noise ratio and the signal strength of the peak of the reference signal reach thresholds.

[0047] As a result, if an abnormality has occurred (No in S21), that is, (1) if the frequency of the peak of the reference signal is not within a predetermined frequency range, or (2) if at least one of the signal-to-noise ratio and the signal strength of the peak of the reference signal does not reach a threshold, the monitoring unit 62 determines that an abnormality has occurred in the electromagnetic field space distribution measuring system 10, and displays "abnormality present" on the display unit 71 (S22). Thereafter, steps S20 and S21 are repeated again.

[0048] On the other hand, if no abnormality has occurred or if the abnormality has been resolved (Yes in S21), the measurement (S10 to S16) is performed in the first operation mode shown in Fig. 5. In other words, the measurement is started, and even if an abnormality occurs, the measurement is not stopped midway and is carried out to the end.

[0049] In this way, in the second operation mode, if there is an abnormality before measurement, the measurement will not be started until the abnormality is resolved. However, after the measurement starts, it enters the first operation mode, and the measurement will be executed until the end without interruption even if there is an abnormality from before the measurement to during the measurement.

[0050] In the flowchart of FIG. 6, when an abnormality is detected (No in S21), the initialization (S20) and abnormality diagnosis (S21) of the electromagnetic field spatial distribution measurement system 10 are repeated until the abnormality is resolved. Instead of this, when a certain number of repetitions is exceeded, or when there is an instruction from the user or the like, this repetitive process may be terminated

[0051] FIG. 7 is a block diagram showing the configuration of an electromagnetic field spatial distribution measurement system 11 including an abnormality monitoring system 80 according to the first modification of the embodiment. In this electromagnetic field spatial distribution measurement system 11, unlike the above embodiment where the distributor 51 is connected to the output side of the second photodetector 28, it is connected to the input side of the second photodetector 28. That is, the distributor 51 distributes the intermediate frequency optical signal output from the second optical filter 26 with a branching ratio of n:m (m < n), outputs the optical signal corresponding to m of the distributed signals to the frequency analyzer 62a (input terminal for this optical signal) of the monitoring unit 62, and outputs the optical signal corresponding to n of the distributed signals to the second photodetector 28. Even in the electromagnetic field spatial distribution measurement system 11 provided with such a distributor 51, the same processing as the electromagnetic field spatial distribution measurement system 10 and the abnormality monitoring system 80 according to the above embodiment is possible.

[0052] 8 is a block diagram showing the configuration of an electromagnetic field space distribution measuring system 12 equipped with an anomaly monitoring system 80 according to a second modified example of the embodiment. In this electromagnetic field space distribution measuring system 12, the second EO probe 22, the second optical circulator 24, the second optical filter 26, and the second photodetector 28 in the embodiment shown in FIG. 1 are replaced with a reference signal generator 42. The reference signal generator 42 is, for example, an arbitrary signal generating device capable of generating an electrical signal of an arbitrary frequency and an arbitrary waveform, and is set to generate a signal of the same frequency as the reference signal output by the second photodetector 28.

[0053] In the above embodiment, the second EO probe 22, the second optical circulator 24, the second optical filter 26, and the second photodetector 28 generate a second IF signal (frequency f IF ) was generated, but in the electromagnetic field space distribution measuring system 12 according to this modification, instead, a reference signal generator 42 generates a second IF signal (frequency f IF ) is generated. The electromagnetic field space distribution measuring system 12 including such a reference signal generator 42 can also perform processing similar to that of the electromagnetic field space distribution measuring system 10 and the anomaly monitoring system 80 according to the above-described embodiments.

[0054] In this modification, the reference signal generator 42 is a device that generates a reference signal as an electrical signal, but it may also be a device that generates a reference signal as an optical signal. That is, the reference signal generator 42 may be replaced with the second EO probe 22 in the electromagnetic field spatial distribution measurement system 10 according to the above embodiment, or may be replaced with a combination of the second EO probe 22 and the second optical circulator 24, or may be replaced with a combination of the second EO probe 22, the second optical circulator 24, and the second optical filter 26.

[0055] 9 is a block diagram showing the configuration of an electromagnetic field spatial distribution measuring system 13 including an anomaly monitoring system 80 according to a third modified example of the embodiment. This electromagnetic field spatial distribution measuring system 13 is an imaging device that measures the spatial distribution of an electromagnetic field due to an electromagnetic field (RF signal) radiated from an antenna 122, and includes light-emitting elements 101 and 102, optical amplifiers 103 and 104, branching filters 105 and 106, an optical shifter 109, multiplexers 107 and 108, an electromagnetic radiator 110 (a photoelectric converter 121 and an antenna 122), an optical probe 130, a sweep device 40, an optical circulator 112, an optical filter 113, a light-receiving element 114, a reference signal generator 111, an amplitude / phase detector 115, and an anomaly monitoring system 80.

[0056] The first light of the first frequency f1 output from the light-emitting element 101, which is an example of a first light source, is amplified by the optical amplifier 103, then split by the splitter 105, and input to the optical shifter 109 and the multiplexer 108.

[0057] On the other hand, the second light of the second frequency f2 output from the light-emitting element 102, which is an example of the second light source, is amplified by the optical amplifier 104, then split by the splitter 106, and input to the multiplexer 107 and the multiplexer 108.

[0058] The light input to the optical shifter 109 is frequency shifted by a reference signal of frequency fs from a reference signal generator 111, and then multiplexed with light of frequency f2 by a multiplexer 107. The multiplexed light is then split by a splitter 52 and input to an electromagnetic emitter 110 and a monitoring unit 62 of a controller 60.

[0059] Light input to the electromagnetic emitter 110 is converted by the photoelectric converter 121 into an electromagnetic wave having a frequency of (f1-f2-fs), and then emitted by the antenna 122 as electromagnetic wave 123 toward the space in which the target object or the like is placed.

[0060] Electromagnetic waves 123 emitted from antenna 122 pass through a space in which an object or the like is placed, are received by optical probe 130, and are input to optical circulator 112 via optical fiber 131. Optical probe 130 is a measurement probe that scans a measurement point under the control of measurement control unit 61 of controller 60.

[0061] On the other hand, the first light of frequency f1 and the second light of frequency f2 input to the multiplexer 108 are multiplexed by the multiplexer 108 and then input to the optical circulator 112, where they interact with the light from the optical probe 130 and are then output to the optical filter 113, which filters out only the component light of frequencies f1 and (f1-fs) or the component light of frequencies f2 and (f2+fs), which are then photoelectrically converted by the photodetector 114 into an electrical signal and input to the amplitude / phase detector 115.

[0062] The amplitude / phase detector 115 performs synchronous detection using a reference signal of frequency fs from the reference signal generator 111, thereby detecting the amplitude and phase of the signal component that is synchronized with the reference signal among the signals input to the amplitude / phase detector 115 from the light receiving element 114, and information indicating the detected amplitude and phase is input to the measurement control unit 61 of the controller 60.

[0063] In the electromagnetic field space distribution measurement system 13 according to this modified example configured as described above, the multiplexer 107 that outputs light to the distributor 52 can be considered a reference signal generator that generates a reference signal. In this case, the measurement probe that detects the electric field while scanning a measurement point in an electromagnetic field that has a certain relationship with the reference signal corresponds to the optical probe 130. Furthermore, the signal processing unit that calculates the amplitude and phase of the electric field indicated by the measurement signal output from the measurement probe and outputs the calculated amplitude and phase as the measurement result corresponds to the optical circulator 112, optical filter 113, light receiving element 114, and amplitude / phase detector 115 (processing units from the optical filter 113 to the amplitude / phase detector 115).

[0064] The abnormality monitoring system 80 in the electromagnetic field space distribution measuring system 13 according to this modification has the same functions as the abnormality monitoring system 80 in the electromagnetic field space distribution measuring system 10 according to the above embodiment.

[0065] As described above, the anomaly monitoring system 80 according to the present disclosure is a system for monitoring anomalies in the electromagnetic field spatial distribution measuring system 10 and the like, and the electromagnetic field spatial distribution measuring system 10 includes a reference signal generator (second EO probe 22, multiplexer 107, etc.) that generates a reference signal, a measurement probe (first EO probe 21, optical probe 130, etc.) that detects an electric field while scanning a measurement point in an electromagnetic field that has a certain relationship with the reference signal, and a signal processing unit (signal processing unit 30, optical filter 113 to amplitude / phase detector 115, etc.) that calculates the amplitude and phase of the electric field indicated by the measurement signal output from the measurement probe and outputs the calculated amplitude and phase as the measurement result, and the anomaly monitoring system 80 includes a distributor 50, etc. that distributes the reference signal, and a monitoring unit 62 that determines whether or not an anomaly exists in the electromagnetic field spatial distribution measuring system 10 based on the reference signal distributed by the distributor 50, etc.

[0066] More specifically, in the electromagnetic field spatial distribution measuring system 10 of the first embodiment etc., the reference signal generator is a reference probe (second EO probe 22) that detects the electric field while being fixed in the electromagnetic field, and the signal processing unit mixes the reference signal output from the reference probe with the measurement signal to calculate the amplitude and phase of the electric field indicated by the measurement signal using the reference signal as a reference, and outputs the calculated amplitude and phase as the measurement results.

[0067] Furthermore, in the electromagnetic field space distribution measuring system 13 according to the third modification, the electromagnetic field space distribution measuring system 13 further includes a first light source (light-emitting element 101) that outputs a first light of a first frequency and a second light source (light-emitting element 102) that outputs a second light of a second frequency, the reference signal is light obtained by combining the second light with light of a frequency obtained by shifting the frequency of the first light by a fixed amount, and is used to generate an electromagnetic field, and the signal processing unit (optical filter 113 to amplitude / phase detector 115) processes the measurement signal using the light obtained by combining the first light and the second light, thereby outputting the amplitude and phase as the measurement result.

[0068] In this way, by utilizing a reference signal that is reliably generated in the electromagnetic field space distribution measurement system 10 or the like, abnormalities in the electromagnetic field space distribution measurement system 10, which is not necessarily easy to determine whether it is operating normally or an abnormality has occurred, can be monitored, and the determination of whether it is operating normally or an abnormality can be made clearly. This improves the reliability of measurements by the electromagnetic field space distribution measurement system 10. It is also possible to avoid wasting time when measurements are performed without realizing that an abnormality has occurred.

[0069] Here, the abnormality monitoring system 80 further includes a notification unit (display unit 71) that notifies the user of the abnormality when the monitoring unit 62 determines that an abnormality has occurred in the electromagnetic field space distribution measuring system 10. This allows the user to know in real time that an abnormality has occurred.

[0070] Furthermore, when the monitoring unit 62 determines that there is an abnormality in the electromagnetic field space distribution measuring system 10, it invalidates the measurement results output by the signal processing unit 30. This prevents measurement results obtained when an abnormality has occurred from being mistakenly treated as normal measurement results.

[0071] Furthermore, the monitoring unit 62 determines whether there is an abnormality in the electromagnetic field space distribution measurement system 10 before scanning by the measurement probe (first EO probe 21) is started, and if it determines that there is an abnormality in the electromagnetic field space distribution measurement system 10, it performs control to prevent scanning by the measurement probe (first EO probe 21) from starting. This makes it possible to avoid measurement being performed in a state where an abnormality has occurred.

[0072] The reference signal is an optical signal, and the electromagnetic field spatial distribution measurement system 10 further includes a frequency converter that converts the reference signal into an electrical signal with an intermediate frequency lower than the frequency of the reference signal, and the distributor 50 distributes the electrical signal output from the frequency converter. By monitoring the reference signal converted to a low frequency, the frequency analyzer does not need to be an expensive frequency analyzer that can handle high frequencies. This also makes it easy to create an abnormality detection program, and in cooperation with the electromagnetic field spatial distribution measurement system 10 itself, it also makes it easy to handle abnormality notification, measurement invalidation, and other similar processes.

[0073] Furthermore, the monitoring unit 62 generates a spectrum of the reference signal distributed by the distributor 50, and determines that there is an abnormality in the electromagnetic field space distribution measuring system 10 when (1) the frequency of a peak in the generated spectrum is not within a predetermined frequency range, or (2) at least one of the signal-to-noise ratio and signal strength of the peak does not reach a threshold. As a result, the presence or absence of an abnormality is determined for the reference signal using the spectrum, and therefore, an abnormality determination can be performed with higher accuracy than when the presence or absence of an abnormality is determined using a time-domain signal.

[0074] Furthermore, the reference signal may be an optical signal, and the distributor 51 may distribute the reference signal. By branching the optical signal, when an abnormality occurs in the electromagnetic field space distribution measurement system 10, it becomes easier to determine whether the cause is an abnormality in the optical processing system or the electrical processing system at the subsequent stage, or whether the abnormality is in the measurement signal system or the reference signal system.

[0075] Further, the distributor 50 distributes the reference signal at a branching ratio of n:m (m < n), and the monitoring unit 62 determines the presence or absence of an abnormality in the electromagnetic field spatial distribution measurement system 10 based on the optical signal corresponding to m distributed by the distributor 50. Thereby, it becomes possible to monitor the abnormality of the electromagnetic field spatial distribution measurement system 10 in a state where the influence on the electromagnetic field spatial distribution measurement system 10 is suppressed.

[0076] Further, the abnormality monitoring method according to the present disclosure is an abnormality monitoring method by an abnormality monitoring system 80 that monitors the abnormality of the electromagnetic field spatial distribution measurement system 10. The electromagnetic field spatial distribution measurement system 10 includes a measurement probe (first EO probe 21) that detects an electric field while scanning measurement points in the electromagnetic field, a reference probe (second EO probe 22) that detects an electric field in a fixed state in the electromagnetic field, or a reference signal generator 42 that generates a reference signal having the same frequency as the reference signal output by the reference probe (second EO probe 22), and a signal processing unit 30 that calculates the amplitude and phase of the electric field indicated by the measurement signal with reference to the reference signal by mixing the measurement signal output from the measurement probe (first EO probe 21) and the reference signal output from the reference probe (second EO probe 22) or the reference signal generator 42, and outputs the calculated amplitude and phase as measurement results. The abnormality monitoring method includes a distribution step of distributing the reference signal and a monitoring step of determining the presence or absence of an abnormality in the electromagnetic field spatial distribution measurement system 10 based on the distributed reference signal.

[0077] Further, the program according to the present disclosure is a program for monitoring the abnormality of the electromagnetic field spatial distribution measurement system 10, and is a program that causes a computer to execute the monitoring step in the above abnormality monitoring method.

[0078] Thereby, by using the reference signal that surely occurs in the electromagnetic field spatial distribution measurement system 10, the abnormality of the electromagnetic field spatial distribution measurement system 10, for which it is not always easy to determine whether it is operating normally or an abnormality has occurred, is monitored, and it is clearly determined whether it is operating normally or an abnormality has occurred.

[0079] The anomaly monitoring system, anomaly monitoring method, and a program according to the present disclosure have been described above based on embodiments and modifications, but the present disclosure is not limited to these embodiments and modifications. As long as they do not deviate from the gist of the present disclosure, various modifications that a person skilled in the art may make to the embodiments or modifications, and other forms constructed by combining some of the components of the embodiments and modifications, are also included within the scope of the present disclosure.

[0080] For example, the measurement system to be monitored for abnormalities is not limited to the configuration of abnormality monitoring system 80 according to the above embodiment. The measurement system to be monitored for abnormalities may be any system that includes a measurement probe, a reference probe, and a signal processing unit, and may convert only the optical signal output by the reference probe into an intermediate frequency electrical signal instead of converting each of the optical signals output by the measurement probe and the reference probe into an intermediate frequency electrical signal, or the measurement probe and reference probe may be of a type that outputs electrical signals instead of optical signals.

[0081] Furthermore, with regard to the distribution of the reference signal, in addition to the distributor 50 that distributes the electrical signal, a distributor 51 that distributes the optical signal may also be provided, and the output signals from the two distributors 50 and 51, or the output signal from one selected from the two distributors 50 and 51 via a selector switch, may be input to the frequency analyzer 62a.

[0082] Furthermore, in addition to the divider 50 that divides the reference signal, a divider that divides the measurement signal may be provided, and the output signals from these two dividers, or the output signal from one of the two dividers selected via a selector switch, may be input to the frequency analyzer 62a.

[0083] Furthermore, in the above embodiment, the monitoring unit 62 determines whether (1) the frequency of the peak of the reference signal is within a predetermined frequency range, and (2) both the signal-to-noise ratio and the signal strength of the peak of the reference signal have reached a threshold value. However, the conditions are not limited to these, and for example, the number of conditions may be reduced, and the monitoring unit 62 may determine whether (1) the frequency of the peak of the reference signal is within a predetermined frequency range, and (2) the signal-to-noise ratio of the peak of the reference signal has reached a threshold value. [Industrial Applicability]

[0084] The abnormality monitoring system according to the present disclosure can be used as a device for monitoring abnormalities in an electromagnetic field spatial distribution measurement system, for example, as a device for monitoring abnormalities in an imaging device that uses measurements of electromagnetic field spatial distribution to non-destructively visualize the inside of an object. [Explanation of symbols]

[0085] 10, 11, 12, 13 Electromagnetic field spatial distribution measurement system 15, 122 Antenna 20 EO type detector 21 First EO Probe 22 Second EO Probe 23 First Optical Circulator 24 Second optical circulator 25 First Optical Filter 26 Second Optical Filter 27 First photodetector (PD) 28 Second Photodetector (PD) 30 Signal Processing Unit 31, 111 Reference signal generator 32 First Multiplier 33 Filters 34 Second Multiplier 35 Synchronous detector 40 Sweep equipment 42 Reference Signal Generator 50, 51, 52 distributor 60 Controller 61 Measurement control section 62 Monitoring Department 62a Frequency analyzer 70 Input section 71 Display section 80 Abnormality Monitoring System 101, 102 Light-emitting element 103, 104 Optical amplifier 105, 106 Duplexer 107, 108 Multiplexer 109 Optical Shifter 110 Electromagnetic Radiator 112 Optical Circulator 113 Optical Filter 114 Photodetector 115 Amplitude / Phase Detector 121 Photoelectric converter 123 Electromagnetic Waves 130 Optical Probe 131 Optical Fiber

Claims

1. An abnormality monitoring system for monitoring an abnormality in an electromagnetic field space distribution measurement system, The electromagnetic field spatial distribution measurement system includes: a reference signal generator for generating a reference signal; a measurement probe that detects an electric field while scanning a measurement point in an electromagnetic field having a certain relationship with the reference signal; a signal processing unit that calculates the amplitude and phase of the electric field indicated by the measurement signal output from the measurement probe and outputs the calculated amplitude and phase as a measurement result; The abnormality monitoring system includes: a distributor that distributes the reference signal; a monitoring unit that determines whether or not there is an abnormality in the electromagnetic field space distribution measurement system based on the reference signal distributed by the distributor. Anomaly monitoring system.

2. the reference signal generator is a reference probe that detects an electric field in a fixed state in the electromagnetic field; The signal processing unit mixes the reference signal output from the reference probe with the measurement signal to calculate the amplitude and phase of the electric field indicated by the measurement signal based on the reference signal, and outputs the calculated amplitude and phase as measurement results. The abnormality monitoring system according to claim 1.

3. the electromagnetic field spatial distribution measurement system further includes a first light source that outputs a first light of a first frequency and a second light source that outputs a second light of a second frequency; the reference signal is light obtained by multiplexing the second light with light of a frequency obtained by shifting the frequency of the first light by a certain amount, and is used to generate the electromagnetic field; the signal processing unit processes the measurement signal using light obtained by combining the first light and the second light, and outputs the amplitude and phase as measurement results. The abnormality monitoring system according to claim 1.

4. Further, a notification unit is provided that notifies the user of the abnormality when the monitoring unit determines that the electromagnetic field space distribution measurement system has an abnormality. The abnormality monitoring system according to claim 1.

5. the monitoring unit invalidates the measurement result output by the signal processing unit when determining that there is an abnormality in the electromagnetic field space distribution measurement system. The abnormality monitoring system according to claim 1.

6. the monitoring unit determines whether or not there is an abnormality in the electromagnetic field space distribution measurement system before scanning by the measurement probe is started, and when it determines that there is an abnormality in the electromagnetic field space distribution measurement system, performs control to prevent scanning by the measurement probe from being started. The abnormality monitoring system according to claim 1.

7. the reference signal is an optical signal; the electromagnetic field space distribution measuring system further includes a frequency converter that converts the reference signal into an electric signal having an intermediate frequency lower than a frequency of the reference signal; The divider divides the electrical signal output from the frequency converter. The abnormality monitoring system according to claim 1.

8. The monitoring unit generates a spectrum of the reference signal distributed by the distributor, and determines that there is an abnormality in the electromagnetic field space distribution measurement system when (1) a peak frequency in the generated spectrum is not within a predetermined frequency range, or (2) at least one of a signal-to-noise ratio and a signal strength of the peak does not reach a threshold. The abnormality monitoring system according to claim 1.

9. the reference signal is an optical signal; The distributor distributes the reference signal. The abnormality monitoring system according to claim 1.

10. The distributor distributes the reference signal at a branching ratio of n:m (m<n), the monitoring unit determines whether or not there is an abnormality in the electromagnetic field space distribution measurement system based on the optical signal corresponding to m distributed by the distributor. The abnormality monitoring system according to claim 9.

11. An abnormality monitoring method by an abnormality monitoring system that monitors an abnormality in an electromagnetic field space distribution measurement system, comprising: The electromagnetic field spatial distribution measurement system includes: a reference signal generator for generating a reference signal; a measurement probe that detects an electric field while scanning a measurement point in an electromagnetic field having a certain relationship with the reference signal; a signal processing unit that calculates the amplitude and phase of the electric field indicated by the measurement signal output from the measurement probe and outputs the calculated amplitude and phase as a measurement result; The abnormality monitoring method includes: a distributing step of distributing the reference signal; a monitoring step of determining whether or not there is an abnormality in the electromagnetic field space distribution measurement system based on the distributed reference signal. Anomaly monitoring method.

12. A program for monitoring an abnormality in an electromagnetic field spatial distribution measurement system, A program that causes a computer to execute the monitoring step according to claim 11.

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