Object perspective device, control circuit, storage medium, and object perspective method

Abstract

An object perspective device (10A) generates an image of an electric wave scatterer (30) as a measurement target from a reflected wave (W) of an electric wave containing a plurality of frequencies, which is irradiated to the electric wave scatterer (30) as the measurement target arranged in a measurement region, wherein the object perspective device (10A) has a phase-combined image generation section (28) that generates a phase-combined image in which a plurality of images obtained by performing imaging based on the reflected wave (W) are combined, by performing complex addition for each pixel of the plurality of images.

Description

Technical Field

[0001] This invention relates to an object perspective device, control circuit, storage medium, and object perspective method. Background Technology

[0002] One type of device that illuminates an object as the object of measurement with millimeter waves, terahertz waves, etc., and uses the reflected waves from the object to visualize it is an object visualization device that uses a matched filter (MF) to image the object. This object visualization device illuminates the object with radio waves while moving the transmitting and receiving antennas used for measurement along a predetermined path, receives the reflected waves from the scattering points of the object, and records the timing data of the reflected waves.

[0003] The object-viewing device superimposes reflected waves of various waveforms received from various scattering points, thereby generating the received signal waveform, i.e., the received waveform. If the positional relationship between the measurement area and the transmitting / receiving antenna is known, the object-viewing device can estimate the waveform of the reflected wave from a scattering point located at any coordinate within the measurement area. When performing imaging using multiple-mode (MF), the object-viewing device pre-positions observation points throughout the measurement area, generates an estimated waveform of the reflected wave for each observation point, and obtains the correlation between the estimated waveform and the received waveform, thereby mapping the reflection intensity from each observation point. In this case, the correlation value between the estimated waveform and the received waveform is obtained as a correlation vector with phase information. That is, the correlation vector represents the correlation between the estimated waveform and the received waveform and contains phase information. The object-viewing device can obtain a high correlation value when the observation point and the scattering point are close, and a low correlation value when there are no scattering points near the observation point.

[0004] When performing imaging using multiple frequency radio waves, the object perspective device repeatedly performs the same measurements using multiple frequencies of radio waves. This reduces sidelobes caused by the configuration of the transmitting and receiving antennas and scattering objects around the measurement area. Methods for synthesizing images measured using multiple frequencies of radio waves include power synthesis based on the magnitude of the correlation vector accumulated for each pixel, and phase synthesis based on complex addition considering phase information for each pixel.

[0005] Compared to power combining, phase combining achieves higher sidelobe reduction. However, if the phases of the correlation vectors measured from the same observation point using radio waves of different frequencies are not accurately aligned, the correlation vectors will cancel each other out during complex addition. Therefore, phase combining requires signal processing that considers information about the positional relationship between the observation point and the transmitting and receiving antennas, or the influence of the frequency characteristics of the measurement system.

[0006] One method for achieving phase synthesis involves estimating or pre-measuring the phase shift generated when measuring a pixel using radio waves of different frequencies, subtracting the phase shift from the measurement result, and thereby correcting the phase. Patent Document 1 describes a millimeter-wave image processing apparatus comprising a signal processing unit that processes signals received using an antenna, and a correction signal generating unit disposed outside the signal processing unit. The correction signal generating unit acquires phase shift information applicable to the signal processing unit, and the signal processing unit uses the phase shift information to correct the phase of the radio waves received by the antenna.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2007-256171 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, in the technology of the aforementioned Patent Document 1, a calibration signal generating device is required, which leads to a problem where the device structure becomes complex.

[0012] The present invention was made in view of the above circumstances, and its object is to provide an object perspective device that can accurately see through objects even when the exact distance between the object and the device cannot be determined, through a simple structure.

[0013] Methods for solving problems

[0014] To solve the aforementioned problems and achieve the objective, the object perspective apparatus of the present invention generates an image of the object to be measured based on the reflected waves of radio waves containing multiple frequencies irradiated onto the object to be measured within the measurement area. The object perspective apparatus is characterized by having a phase synthesis image generation unit, which performs complex summation on each pixel of multiple images obtained by imaging based on reflected waves, thereby generating a phase synthesis image composed of the multiple images.

[0015] Invention Effects

[0016] The object perspective device of the present invention has the following effect: even in environments where the accurate distance between the object and the device cannot be determined, it can accurately see through the object through a simple structure. Attached Figure Description

[0017] Figure 1 This is a diagram showing the structure of the object perspective device according to Embodiment 1.

[0018] Figure 2This is a diagram illustrating another example of the antenna movement path used in the object perspective device of Embodiment 1.

[0019] Figure 3 This diagram illustrates the signal generation process performed by the object perspective device in Embodiment 1.

[0020] Figure 4 This is a diagram used to illustrate the observation points set by the object perspective device in Embodiment 1.

[0021] Figure 5 This is a graph used to illustrate the correlation between the estimated waveform of the reflected wave calculated by the object perspective device of Embodiment 1 and the received waveform.

[0022] Figure 6 This is a diagram illustrating the frequency update pattern of the high-frequency signal used in the object perspective device of Embodiment 1.

[0023] Figure 7 This is a diagram illustrating the structure of the orthogonal detector section of the object perspective device in Embodiment 1.

[0024] Figure 8 This is a diagram showing the structure of the waveform recording section of the object perspective device according to Embodiment 1.

[0025] Figure 9 This diagram illustrates the power synthesis image generation process performed by the power synthesis image generation unit of the object perspective device according to Embodiment 1.

[0026] Figure 10 This diagram illustrates the calculation process of the correction phase for each frequency performed by the correction phase calculation unit of the object perspective device of Embodiment 1.

[0027] Figure 11 This diagram illustrates the phase synthesis image generation process performed by the phase synthesis image generation unit of the object perspective device according to Embodiment 1.

[0028] Figure 12 This is a flowchart illustrating the phase synthesis image generation process performed by the object perspective device of Embodiment 1.

[0029] Figure 13 This is a diagram showing the structure of the object perspective device according to Embodiment 2.

[0030] Figure 14 This is a flowchart illustrating the phase synthesis image generation process performed by the object perspective device of Embodiment 3.

[0031] Figure 15This is a diagram used to illustrate the combination of the set of observation coordinates calculated by the object perspective device in Embodiment 3, and the sum of the Euclidean distances in each combination.

[0032] Figure 16 This is a diagram illustrating an example of the structure of the processing circuit in the case where the processing circuit of the object perspective device of Embodiment 1 is implemented by a processor and a memory.

[0033] Figure 17 This is a diagram showing an example of the processing circuit in the case where the object perspective device of Embodiment 1 is configured with dedicated hardware. Detailed Implementation

[0034] Hereinafter, the object perspective device, control circuit, storage medium, and object perspective method according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0035] Implementation Method 1

[0036] Figure 1 This diagram illustrates the structure of the object perspective apparatus according to Embodiment 1. The object perspective apparatus 10A is a device that irradiates a high-frequency electromagnetic wave (such as a millimeter wave or terahertz wave) 30, which is the object to be measured, with electromagnetic waves, and uses the reflected wave W from the electromagnetic wave scatterer 30 to see through the electromagnetic wave scatterer 30. The object perspective apparatus 10A performs imaging using multiple frequency (MF) signals, thereby seeing through the electromagnetic wave scatterer 30. The object perspective apparatus 10A performs MF using a phase synthesis method employing high-frequency signals of multiple frequencies. Furthermore, in Embodiment 1, the object perspective apparatus 10A is designed to see through the electromagnetic wave scatterer 30 in situations where the accurate distance between the object and the electromagnetic wave scatterer 30 cannot be determined.

[0037] The object perspective device 10A includes a transmitting antenna 11, a receiving antenna 12, a quadrature detector 21, a high-frequency signal generator 24, a waveform recording unit 22, a position control unit 25, and a frequency control unit 23. Furthermore, the object perspective device 10A includes a power synthesis image generation unit 26, a phase correction calculation unit 27, and a phase synthesis image generation unit 28. Additionally, the transmitting antenna 11 may be a separate structure from the object perspective device 10A. Similarly, the receiving antenna 12 may also be a separate structure from the object perspective device 10A.

[0038] The frequency control unit 23 outputs a frequency command specifying the frequency of the high-frequency signal to the high-frequency signal generator 24, thereby controlling the frequency of the high-frequency signal output from the high-frequency signal generator 24. The frequency control unit 23 updates the frequency of the high-frequency signal specified by the high-frequency signal generator 24 according to a predetermined pattern. The frequency control unit 23 outputs the frequency of the high-frequency signal indicated by the frequency command as frequency data to the waveform recording unit 22.

[0039] The high-frequency signal generator 24 generates a high-frequency signal for use in the measurement according to the frequency command from the frequency control unit 23, and outputs it to the transmitting antenna 11 and the quadrature detector 21.

[0040] The output of the high-frequency signal generator 24 is coupled to the local input of the quadrature detector 21 and the local input of the transmitting antenna 11. The high-frequency signal generator 24 supplies high-frequency signals of various frequencies to the transmitting antenna 11 and the quadrature detector 21. An example of the high-frequency signal generator 24 is a high-frequency signal generator.

[0041] The transmitting antenna 11 is a component that radiates the high-frequency signal output from the high-frequency signal generator 24 into space as an electromagnetic wave. The transmitting antenna 11 irradiates the electromagnetic wave of the high-frequency signal onto the electromagnetic wave scatterer 30, which is the object of measurement. For example, a horn antenna, a patterned antenna formed on a substrate, or an array antenna composed of multiple antennas can be used as the transmitting antenna 11.

[0042] The receiving antenna 12 is a component that receives the reflected wave W from the radio wave scatterer 30. The receiving antenna 12 receives the reflected wave W reflected from multiple radio wave scattering points such as scattering points 1A to 1C, and outputs it to the orthogonal detector 21. For example, a horn antenna, a patterned antenna formed on a substrate, or an array antenna composed of multiple antennas can be used as the receiving antenna 12. Furthermore, the receiving antenna 12 does not necessarily have the same structure as the transmitting antenna 11.

[0043] The position control unit 25 controls at least one of the positions of the transmitting antenna 11 and the receiving antenna 12. The position control unit 25 can control the positions of both the transmitting antenna 11 and the receiving antenna 12, or it can control only the position of the transmitting antenna 11, or it can control only the position of the receiving antenna 12.

[0044] With the position of the receiving antenna 12 fixed, the position control unit 25 controls the position of the transmitting antenna 11. With the position of the transmitting antenna 11 fixed, the position control unit 25 controls the position of the receiving antenna 12.

[0045] The position of the transmitting antenna 11 corresponds to the radio wave radiation direction based on the transmitting antenna 11. The following describes the situation where the position control unit 25 controls the positions of both the transmitting antenna 11 and the receiving antenna 12. Furthermore, assuming the relative positions of the transmitting antenna 11 and the receiving antenna 12 remain unchanged, the position control unit 25 moves the transmitting antenna 11 and the receiving antenna 12 together.

[0046] The position control unit 25 is connected to a conveying mechanism (not shown) equipped with a transmitting antenna 11 and a receiving antenna 12. By controlling the position of the conveying mechanism, the position of the transmitting antenna 11 and the receiving antenna 12 is controlled.

[0047] The position control unit 25 moves the transmitting antenna 11 and the receiving antenna 12 along a predetermined antenna movement path 71, and outputs position data indicating the positions of the transmitting antenna 11 and the receiving antenna 12 to the waveform recording unit 22. When the position of the transmitting antenna 11 is fixed, the position data for the transmitting antenna 11 is a fixed value. Similarly, when the position of the receiving antenna 12 is fixed, the position data for the receiving antenna 12 is a fixed value. The position data output by the position control unit 25 to the waveform recording unit 22 corresponds to the movement command output by the position control unit 25 to the conveying mechanism.

[0048] For example, Figure 1 As shown, the antenna movement path 71 is a path that moves along a circle that surrounds the radio wave scatterer 30, which is the object of measurement. However, the antenna movement path 71 is not limited to a path along a circle.

[0049] Figure 2 This diagram illustrates another example of the antenna movement path used in the object perspective device of Embodiment 1. Antenna movement path 72, another example of antenna movement path 71, is a path that moves the transmitting antenna 11 and the receiving antenna 12 up, down, left, and right within a specific plane. When the plane set in antenna movement path 72 is defined as the XY plane, the position control unit 25 performs various combinations of movement in the X direction and movement in the Y direction, thereby moving the transmitting antenna 11 and the receiving antenna 12 in various directions within the XY plane.

[0050] When the object perspective device 10A uses the antenna movement path 72, it employs an XY stage that allows the transmitting antenna 11 and the receiving antenna 12 to move within the XY plane. The XY stage is a stage that can move in the X-axis direction and the Y-axis direction when two mutually perpendicular axes in a specific plane are set as the X-axis and the Y-axis.

[0051] The quadrature detector 21 down-converts the received signal from the receiving antenna 12 using a high-frequency signal supplied from the high-frequency signal generator 24, thereby obtaining a baseband signal as a complex signal. This baseband signal contains information about the amplitude and phase difference between the high-frequency signal output from the transmitting antenna 11 and the reflected wave received by the receiving antenna 12, i.e., amplitude-phase difference information. The quadrature detector 21 outputs the baseband signal containing the amplitude-phase difference information to the waveform recording unit 22. An example of the quadrature detector 21 is a quadrature detector circuit.

[0052] The waveform recording unit 22 records the received waveform data obtained by converting the baseband signal output from the quadrature detector 21 from an analog signal to a digital signal. The waveform recording unit 22 records the received waveform data, frequency data, and position data, which contain amplitude and phase difference information, in a corresponding manner.

[0053] The power-combined image generation unit 26 uses the received waveform data, frequency data, and position data recorded in the waveform recording unit 22 to generate a power-combined image of the radio wave scatterer 30, which is the object of measurement, using an imaging method employing power combining (MF). The power-combined image is an image generated using an imaging method employing power combining (MF).

[0054] The power combining method is as follows: for all observation points, the correlation value between the estimated waveform and the received waveform, i.e., the correlation vector containing phase information, is calculated for each frequency. Only the magnitude of the obtained correlation vectors is accumulated. The power combining method has the following advantages: even if there are phase deviations among the various correlation vectors, stable imaging can still be achieved because phase is not considered.

[0055] The coordinates of the observation point with the highest reflection intensity in the coordinates of the power composite image generated by the power composite image generation unit 26 are the maximum reflection intensity coordinates. The power composite image generation unit 26 outputs the power composite image data containing the maximum reflection intensity coordinates to the correction phase calculation unit 27.

[0056] The correction phase calculation unit 27 calculates the correction phase Arg(c) for each frequency based on the power combined image output from the power combined image generation unit 26 and the received waveform data, frequency data, and position data recorded in the waveform recording unit 22. n (λ)). In this case, the correction phase calculation unit 27 searches for the maximum reflection intensity coordinate in the power combined image output from the power combined image generation unit 26, and calculates the correction phase Arg(c) at the maximum reflection intensity coordinate at each frequency. n (λ)). The correction phase calculation unit 27 calculates the correction phase Arg(c) for each frequency. n (λ)) is output to the phase synthesis image generation unit 28.

[0057] The phase synthesis image generation unit 28 generates images based on the corrected phase Arg(c) of each frequency output from the corrected phase calculation unit 27. n (λ) and the received waveform data, frequency data, and position data recorded in the waveform recording unit 22 are used to generate a phase-composite image. In this case, the phase-composite image generation unit 28 generates the phase-composite image using a phase-composite imaging method. The phase-composite image is an image generated by an imaging method using phase-composite MF. The phase-composite image generation unit 28 outputs the phase-composite image as the imaging result to an external device such as a display device.

[0058] Here, the relationship between the timing data of the reflected wave obtained by the measurement system of the object perspective device 10A and the received signal will be explained. Figure 3This diagram illustrates the signal generation process performed by the object perspective device in Embodiment 1.

[0059] like Figure 3 As shown, the reflected waves from scattering points 1A to 1C at different locations have different waveforms. The receiving antenna 12 makes the timing data of the reflected waves coincide, thereby generating a received signal. Here, the receiving antenna 12 makes the reflected waves from scattering point 1A, scattering point 1B, and scattering point 1C coincide, thereby generating the waveform of the received signal, i.e., the received waveform. Thus, the received signal is obtained by coinciding the reflected waves from all scattering points.

[0060] In this case, if the positional relationship between the measurement area where the scattering point is located and the positions of the transmitting antenna 11 and the receiving antenna 12 (i.e., the positions of the transmitting and receiving antennas) is known, the waveform of the reflected wave from a scattering point located at any coordinate on the measurement area can be estimated. The position of the measurement area is pre-registered in the object perspective device 10A. The positions of the transmitting and receiving antennas correspond to the position data recorded by the waveform recording unit 22 by the position control unit 25.

[0061] When performing imaging using MF, the object perspective device 10A pre-sets observation points in a comprehensive manner within the measurement area and generates an estimated waveform of the reflected wave for each observation point. Figure 4 This is a diagram used to illustrate the observation points set by the object perspective device in Embodiment 1.

[0062] The object perspective device 10A comprehensively sets observation points at various locations within the measurement area. Figure 4 The image shows the object perspective device 10A with observation points 2A to 2C set.

[0063] The object perspective device 10A obtains the correlation between the estimated waveform of the reflected wave and the received waveform, thereby mapping the reflection intensity from each observation point. Figure 5 This is a graph used to illustrate the correlation between the estimated waveform of the reflected wave calculated by the object perspective device of Embodiment 1 and the received waveform.

[0064] The power combining image generation unit 26 of the object perspective device 10A obtains the correlation between the estimated waveform of the reflected wave and the received waveform. Specifically, the power combining image generation unit 26 obtains the correlation between the estimated waveform of the reflected wave at observation point 2A and the received waveform. Furthermore, the power combining image generation unit 26 obtains the correlation between the estimated waveform of the reflected wave at observation point 2B and the received waveform, and also obtains the correlation between the estimated waveform of the reflected wave at observation point 2C and the received waveform.

[0065] The power combining image generation unit 26 maps the reflection intensity from each observation point based on the correlation result between the estimated waveform representing the reflected wave and the received waveform. In this case, the correlation value is obtained as a correlation vector with phase information. A high correlation value is obtained when the distance between the observation point and the scattering point is close, and a low correlation value is obtained when there is no scattering point near the observation point.

[0066] In the imaging using MF performed by the object perspective device 10A, the same measurement is repeatedly performed using multiple frequencies, thereby reducing sidelobes caused by the configuration of the transmitting antenna 11 and the receiving antenna 12 and by scattering objects located around the radio wave scatterer 30.

[0067] When synthesizing images measured at multiple frequencies, the object perspective device 10A uses both a power synthesis method that accumulates the correlation vector for each pixel and a phase synthesis method that performs complex addition considering phase information for each pixel.

[0068] In the phase synthesis method, if the phases of the correlation vectors of the same observation point measured at different frequencies are not made to be exactly consistent, the correlation vectors will be canceled out when the complex numbers are added. Therefore, the object perspective device 10A performs signal processing that takes into account the positional relationship between the position of the observation point and the position of the transmitting and receiving antennas, as well as the influence of the frequency characteristics of the measurement system.

[0069] Here, a summary of the phase-composite image generation process performed by the object perspective device 10A is explained. When the object perspective device 10A synthesizes images measured at multiple frequencies using a phase-composite method, it removes phase shifts contained in the observation system to ensure the phase consistency of the correlation vectors of the same observation point measured at different frequencies. That is, to achieve phase synthesis, the object perspective device 10A subtracts the phase shift of the correlation vector generated when measuring a pixel at different frequencies from the phase of the measurement result, thereby correcting the phase of the radio waves.

[0070] exist Figure 4 In the measurement system shown, the reciprocating propagation distance between the transmitting and receiving antenna positions at time t and a certain observation point n is denoted as d. n At time (t), the phase θ(t, λ) of the received signal is expressed by the following equation (1). The wavelength of the radio wave used in the measurement is wavelength λ, and the fixed phase offset included in the measurement system for wavelength λ is...

[0071]

[0072] Furthermore, without considering the fixed phase shift included in the measurement system, the estimated value θ^(t, λ) of the reflected wave phase from the observation point n at time t is expressed by the following equation (2). θ^ indicates a hat symbol directly above "θ". The fixed error between the actual distance between the transmitting and receiving antenna positions and the observation point and the estimated value is E.

[0073]

[0074] The reflected wave y from observation point n at time t n (t, λ) and their estimated value y n ^(t, λ) is expressed using equations (1) and (2), and further expressed by equations (3) and (4) below. n ^ indicates in "y n The hat symbol is located directly above the character.

[0075] y n (t, λ)=exp{-jθ(t, λ)}…(3)

[0076]

[0077] Furthermore, to simplify the conditions, we assume that the amplitude variation of the reflected wave is negligible. In this case, the wavelength λ and the correlation value c at the observation point n are... n (λ) is represented by the following equation (5).

[0078]

[0079] As shown in equation (5), it can be seen that the phase component of the correlation vector at each observation point depends only on the wavelength λ of the radio wave used in the measurement, and not on the location of the observation point. Therefore, the object perspective device 10A of this embodiment utilizes the fact that the phase component of the correlation vector at each observation point depends only on the wavelength λ of the radio wave used in the measurement, and not on the nature of the location of the observation point. The object perspective device 10A calculates the phase Arg(c) of the correlation vector at the coordinates (calibration coordinates) where the reflection intensity is greater than a specific value in the measurement area for each frequency. n (λ)), using the phase Arg(c n (λ) is used as the correction phase when synthesizing frequency.

[0080] The object perspective device 10A corrects the image at each frequency using a phase correction method and then synthesizes the images to generate a phase-synthesized image. Thus, the object perspective device 10A avoids the cancellation of correlation vectors when performing phase synthesis on images acquired at different frequencies.

[0081] The following is a detailed explanation of the structure and operation of each structural element of the object perspective device 10A. Figure 6This is a diagram illustrating the frequency update pattern of the high-frequency signal used in the object perspective device of Embodiment 1. Figure 6 The horizontal axis of the graph shown represents time. Figure 6 The vertical axis of the graph shown above represents the position of the transmitting and receiving antennas. Figure 6 The vertical axis of the graph shown in the lower layer is the frequency specified by the frequency control unit 23 for the high-frequency signal generation unit 24.

[0082] The position control unit 25 moves the transmitting antenna 11 and the receiving antenna 12 at a fixed speed. Considering the frequency update mode PT for the high-frequency signal, the following mode is considered: Figure 6 As shown, the frequency is repeated in a stepped manner within a certain range for the transmit and receive antenna positions set by the position control unit 25.

[0083] exist Figure 6 The graph shown above illustrates how the position control unit 25 controls the positions of the transmitting antenna 11 and the receiving antenna 12 so that the positions of the transmitting and receiving antennas are successively position P1, position P2, and position P3.

[0084] In addition, Figure 6 The lower layer graph shows the frequency control unit 23 controlling the frequency to increase it in a stepwise manner, such as frequency F1, frequency F2, and frequency F3. Frequency F1 is the frequency when the transmitting and receiving antennas are at position P1. Furthermore, frequency F2 is the frequency when the transmitting and receiving antennas are at position P2, and frequency F3 is the frequency when the transmitting and receiving antennas are at position P3.

[0085] After the frequency reaches a specific value, the frequency control unit 23 controls the frequency again to increase it in a stepwise manner, such as frequency F1, frequency F2, and frequency F3. The frequency control unit 23 repeats these processes.

[0086] in addition, Figure 6 The update mode PT shown is just one example; the combination of frequency and transmit / receive antenna positions can also be recombined, and the order of measurements can also be changed.

[0087] Here, a specific example of the orthogonal detector 21 will be explained. Figure 7 This is a diagram illustrating the structure of the orthogonal detector section of the object perspective device according to Embodiment 1. The orthogonal detector section 21 includes mixers 31 and 32 and a 90-degree phase section 33. An example of the 90-degree phase section 33 is a 90-degree phaser.

[0088] The high-frequency signal supplied from the high-frequency signal generator 24 is locally input to the quadrature detector 21, and the received signal is input from the receiving antenna 12 to the quadrature detector 21. The high-frequency signal from the high-frequency signal generator 24 is input to the 90-degree phase unit 33 and the mixer 32. The received signal from the receiving antenna 12 is input to the mixer 31 and the mixer 32.

[0089] The 90-degree phase unit 33 generates a high-frequency signal with a 90-degree phase difference at the same frequency based on the high-frequency signal, and outputs it to the mixer 31. Thus, the high-frequency signal from the high-frequency signal generator 24 is directly input to the mixer 32, and the high-frequency signal with a 90-degree phase difference at the same frequency relative to the high-frequency signal from the high-frequency signal generator 24 is input to the mixer 31.

[0090] Mixer 32 mixes the high-frequency signal from high-frequency signal generator 24 and the received signal and outputs the result. Mixer 31 mixes the high-frequency signal with a 90-degree phase difference and the received signal and outputs the result. As a result, quadrature detector 21 down-converts the received signal output from receiving antenna 12, calculates the baseband signal (received waveform data) as a complex signal, and outputs it to waveform recording unit 22.

[0091] Next, the detailed structure and operation of the waveform recording unit 22 will be explained. The waveform recording unit 22 has a memory unit that records the received waveform data as a complex signal output from the quadrature detector unit 21, the position data output from the position control unit 25, and the frequency data output from the frequency control unit 23.

[0092] Figure 8 This is a diagram showing the structure of the waveform recording unit of the object perspective device according to Embodiment 1. The waveform recording unit 22 has a memory unit 41, which stores correspondence information 44 that matches received waveform data, frequency data, and position data represented by complex signals.

[0093] In addition, the waveform recording unit 22 has ADCs (Analog to Digital Converters) 42 and 43, which convert the complex signals output from the quadrature detector unit 21 into digital signals and record them in the memory unit 41.

[0094] ADC42 converts the complex signal output from the mixer 31 of the quadrature detector 21 into a digital signal and records it in the memory unit 41. ADC43 converts the complex signal output from the mixer 32 of the quadrature detector 21 into a digital signal and records it in the memory unit 41.

[0095] Figure 8 The corresponding information 44 shown is in the setting Figure 6The information stored in the memory unit 41 is based on the location and frequency of the transmitting and receiving antennas shown.

[0096] The frequency data, position data, and received waveform data stored in the corresponding information 44 are read out by the power combining image generation unit 26, the phase correction calculation unit 27, and the phase combining image generation unit 28. For example, the received waveform r1 of the received waveform data corresponds to the frequency F1 of the frequency data and the position P1 of the position data.

[0097] Next, the detailed structure and operation of the power combining image generation unit 26 will be explained. The power combining image generation unit 26 reads the received waveform data, frequency data, and position data recorded in the waveform recording unit 22. The power combining image generation unit 26 uses the received waveform data, frequency data, and position data recorded in the waveform recording unit 22 to generate a power combining image.

[0098] Figure 9 This diagram illustrates the power-combining image generation process performed by the power-combining image generation unit of the object perspective device according to Embodiment 1. Figure 9 The diagram shows the relationship between the data read from the waveform recording unit 22 by the power combining image generation unit 26, namely the correspondence information 44, and the power combining image generated using the read correspondence information 44.

[0099] The power combining image generation unit 26 reads the corresponding information 44 from the waveform recording unit 22, which is information that maps the received waveform data, frequency data, and position data. The power combining image generation unit 26 divides the read corresponding information 44 into data of the same frequency and generates an image using MF for each frequency.

[0100] Here, we show the case where the power combining image generation unit 26 generates image 51 based on data of frequency F1, image 52 based on data of frequency F2, and image 53 based on data of frequency F3.

[0101] Then, the power-combined image generation unit 26 combines the images generated according to each frequency using a power-combining method to generate a single power-combined image. Figure 9 The image shows a case where the power combining image generation unit 26 combines images 51 to 53 using a power combining method to generate a power combining image 55.

[0102] Next, the detailed structure and operation of the correction phase calculation unit 27 will be explained. The correction phase calculation unit 27 calculates the correction phase Arg(c) for each frequency based on the power composite image output from the power composite image generation unit 26 and the received waveform data, frequency data, and position data recorded in the waveform recording unit 22. n (λ)).

[0103] Figure 10 This diagram illustrates the calculation process of the correction phase for each frequency performed by the correction phase calculation unit of the object perspective device in Embodiment 1. Figure 10 In this process, the correction phase calculation unit 27 uses the power synthesis image 55 and corresponding information 44 to calculate the correction phase Arg(c) for each frequency. n The case of (λ) will be explained.

[0104] The phase correction calculation unit 27 divides the read corresponding information 44 into data of the same frequency. Furthermore, the phase correction calculation unit 27 searches for the maximum reflection intensity coordinates of the power composite image 55 output from the power composite image generation unit 26. Here, the case where the maximum reflection intensity coordinates are at observation point 2A will be explained.

[0105] The correction phase calculation unit 27 calculates the correction phase Arg(c) of the observation point 2A, which serves as the coordinate of the maximum reflection intensity, for each frequency. n (λ)). Specifically, the correction phase calculation unit 27 calculates the phases of frequencies F1 to F3 at observation point 2A. The phases of frequencies F1 to F3 at observation point 2A are used to generate the correction phases Arg(c) of images 51 to 53 when generating the power composite image 55. n (λ)).

[0106] That is, the phase Arg(c) of frequency F1 at observation point 2A n (λ)) is used to correct the phase Arg(c) of image 51 when generating power-synthesized image 55. n Similarly, the phase Arg(c) of frequency F2 at observation point 2A n (λ)) is used to correct the phase Arg(c) of image 52 when generating power-synthesized image 55. n (λ)). The phase Arg(c) of frequency F3 at observation point 2A. n (λ)) is used to correct the phase Arg(c) of image 53 when generating power-synthesized image 55. n (λ)). In Figure 10 In the process, the phase correction Arg(c) is used. A (λ) represents the corrected phase of frequencies F1 to F3.

[0107] Next, the detailed structure and operation of the phase synthesis image generation unit 28 will be explained. The phase synthesis image generation unit 28 generates the image based on the correction phase Arg(c) output from the correction phase calculation unit 27 for each frequency. n (λ) and the received waveform data, frequency data and position data recorded in the waveform recording unit 22 are used to generate a phase composite image.

[0108] Figure 11This diagram illustrates the phase-composite image generation process performed by the phase-composite image generation unit of the object perspective device in Embodiment 1. Figure 11 In the process, the phase-synthesized image generation unit 28 uses the corrected phase Arg(c) method. n The process of generating a phase composite image 56 using (λ) and corresponding information 44 is explained.

[0109] The phase-composite image generation unit 28 divides the corresponding information 44 read from the waveform recording unit 22 into data of the same frequency, and generates images 51-53 using MF for each frequency. Alternatively, the phase-composite image generation unit 28 can also obtain images 51-53 of each frequency using MF from the power-composite image generation unit 26.

[0110] The phase synthesis image generation unit 28 reverses the correlation vector of each pixel in the images 51-53 generated according to each frequency to correct the phase correction Arg(c) calculated by the phase calculation unit 27 for each frequency by rotating the correlation vector of each pixel in reverse. n (λ)) are then added together to generate a phase composite image 56. This phase composite image 56 corresponds to the image in the measurement area.

[0111] In this way, the object perspective device 10A obtains coordinates of reflection intensity greater than a specific value (e.g., coordinates of maximum reflection intensity) within the measurement area, and calculates the phase Arg(c) of the correlation vector according to each frequency. n (λ)). The object perspective device 10A uses the phase Arg(c) n (λ) is used as the correction phase Arg(c) n (λ)), thereby avoiding the cancellation of correlation vectors when performing phase synthesis on images 51–53 acquired at different frequencies.

[0112] Furthermore, the object perspective device 10A selects coordinates (e.g., coordinates of maximum reflection intensity) from images 51-53 synthesized by power combining, where the reflection intensity is stronger than a specific value, as the coordinates for calculating the corrected phase Arg(c). n The calibration coordinates of (λ)). Therefore, the object perspective device 10A can use the calibration phase Arg(c) without configuring a correction signal generator in the measurement area and without setting up a correction scatterer at known coordinates. n (λ)) Generates a phase composite image in the measurement area 56.

[0113] Furthermore, when the object perspective device 10A corrects the phase of the images 51-53 generated according to each frequency, the correction signal generating device does not need to periodically generate correction signals, and it does not need to stop the measurement of reflected waves during the phase correction process. Moreover, the object perspective device 10A does not require the placement of an RFID (Radio Frequency Identification) tag, for example, as a scattering object for correction, at an accurate location within the measurement environment; therefore, the measurement environment is not limited.

[0114] Next, the phase synthesis image generation process performed by the object perspective device 10A will be explained. Figure 12 This is a flowchart illustrating the phase synthesis image generation process performed by the object perspective apparatus of Embodiment 1. The object perspective apparatus 10A receives reflected waves while changing the frequency and the position of the transmitting and receiving antennas, and records the received waveform data as information of the reflected waves (step S10).

[0115] Specifically, the position control unit 25 controls the position of the transmitting and receiving antennas, and the frequency control unit 23 controls the frequency. After receiving the reflected wave from the radio wave scatterer 30, the receiving antenna 12 outputs the received signal to the quadrature detector 21. The quadrature detector 21 uses the received signal from the receiving antenna 12 and the high-frequency signal from the high-frequency signal generator 24 to generate a baseband signal as a complex signal.

[0116] The waveform recording unit 22 generates and records the received waveform data based on the baseband signal. Furthermore, the waveform recording unit 22 records the position data output by the position control unit 25 and the frequency data output by the frequency control unit 23, corresponding to the received waveform data.

[0117] The power combining image generation unit 26 generates a power combining image using the received waveform data, frequency data, and position data recorded in the waveform recording unit 22 (step S20).

[0118] The phase correction calculation unit 27 searches for the coordinates of the maximum reflection intensity within the power composite image (step S30). The phase correction calculation unit 27 calculates the phase of the correlation vector at the coordinates of the maximum reflection intensity for each frequency as the correction phase (step S40). The phase composite image generation unit 28 generates a phase composite image using the correction phase (step S50).

[0119] Thus, in Embodiment 1, the object perspective device 10A performs complex summation on each pixel of multiple images obtained by imaging based on reflected waves from the radio wave scatterer 30, thereby generating a phase composite image synthesized from the multiple images. Therefore, the object perspective device 10A can determine the correction phase amount at each frequency required for phase synthesis of images measured using multiple frequencies without setting up a correction signal generating device in the measurement area or a correction scatterer at known coordinates. Therefore, even in environments where the accurate distance between the object perspective device 10A and the radio wave scatterer 30 cannot be measured, the object perspective device 10A can accurately perceive the radio wave scatterer 30 using multiple frequencies of radio waves through a simple structure.

[0120] Implementation Method 2

[0121] Next, use Figure 13 Embodiment 2 will be described. In Embodiment 2, the transmitting antenna 11 and the receiving antenna 12 are fixed, while the radio wave scatterer 30 is moved.

[0122] Figure 13 This is a diagram showing the structure of the object perspective device according to Embodiment 2. Figure 13 The realization and implementation of each structural element Figure 1 Structural elements with the same function as those in the object perspective device 10A of Embodiment 1 shown are labeled with the same reference numerals, and repeated descriptions are omitted.

[0123] The object perspective device 10B differs from the object perspective device 10A in its measurement system. Instead of fixing the transmitting antenna 11 and receiving antenna 12, the object perspective device 10B moves the radio wave scatterer 30, which is the object being measured. The object perspective device 10B has a rotary table 50 on which the object being measured is placed and rotated.

[0124] The position control unit 25 of the object perspective device 10B controls the rotational position of the rotary table 50. As the rotary table 50 rotates, the radio wave scatterer 30 reflects radio waves at various positions. Consequently, the receiving antenna 12 of the object perspective device 10B receives the same reflected wave W as the object perspective device 10A. Therefore, the object perspective device 10B can generate a phase-composite image through the same processing as the object perspective device 10A.

[0125] In addition, Figure 13 The diagram shows a structure in which the radio wave scatterer 30 is rotated by a rotating stage 50. However, the object perspective device 10B can also replace the rotating stage 50 and be used in Embodiment 1. Figure 2 The mechanism described in the text, such as the XY stage, causes the radio wave scatterer 30 to move.

[0126] Thus, in Embodiment 2, the object perspective device 10B rotates the radio wave scatterer 30 via the rotary table 50, and generates a phase-composite image through the same processing as the object perspective device 10A. Therefore, similar to the object perspective device 10A, the object perspective device 10B can accurately perceive the radio wave scatterer 30 using multiple frequencies of radio waves through a simple structure, even in environments where the precise distance between itself and the radio wave scatterer 30 cannot be determined.

[0127] Furthermore, since the object perspective device 10B can fix the position of the transmitting and receiving antennas, it is not necessary to consider the movement of the wiring connecting the transmitting antenna 11 and the high-frequency signal generator 24, or the movement of the wiring connecting the receiving antenna 12 and the quadrature detector 21.

[0128] Implementation Method 3

[0129] Next, use Figure 14 Embodiment 3 will be described. In Embodiment 3, the calculation steps for the correction phase in the correction phase calculation unit 27 are different from those in Embodiments 1 and 2.

[0130] The object perspective device in Embodiment 3 can be either object perspective device 10A or object perspective device 10B. In the following description, the case where the object perspective device in Embodiment 3 is object perspective device 10A will be described.

[0131] Figure 14 This is a flowchart illustrating the phase synthesis image generation process performed by the object perspective device of Embodiment 3. The object perspective device 10A performs the same process as step S10 described in Embodiment 1, receiving reflected waves while changing the frequency and the position of the transmitting and receiving antennas, and recording received waveform data as information of the reflected waves (step S110).

[0132] The power combining image generation unit 26 generates a power combining image through the same process as step S20 described in Embodiment 1 (step S120).

[0133] The phase correction calculation unit 27 selects the top M (M is a natural number greater than 2) observation coordinates (i.e., the coordinates of the observation points within the power combined image output by the power combined image generation unit 26) with high reflection intensity (step S130). For the selected M observation coordinates, the phase correction calculation unit 27 calculates the phase correction Arg(c) for each frequency based on the received waveform data, frequency data, and position data recorded in the waveform recording unit 22. n (λ k (n = 1, ..., M, k = 1, ..., K). Where K represents the number of frequencies used in the observation.

[0134] The correction phase calculation unit 27 defines the correction phase Arg(c) represented by the following equation (6), which has each frequency in the elements. n (λ k The corrected phase vector P) n (n=1…M).

[0135] P n =(Arg(c n (λ1)) Arg(c n (λ2)) … Arg(c n (λ K ))) …(6)

[0136] The phase correction calculation unit 27 extracts x (where x is a natural number less than or equal to M) observation coordinates from the selected M observation coordinates. The phase correction calculation unit 27 then selects two observation coordinates from the extracted set L of x observation coordinates. l C2 combinations are used to calculate the Euclidean distance of the corrected phase vector. The corrected phase calculation unit 27 calculates the sum of the Euclidean distances.

[0137] Correction phase calculation unit 27 for M C x The sum of the Euclidean distances for all combinations is calculated, and the combination with the smallest sum of the Euclidean distances for the corrected phase vector is selected. That is, the corrected phase calculation unit 27 selects the x observation points with the closest phase for each frequency from the upper M observation coordinates (step S140).

[0138] The correction phase calculation unit 27 calculates the average value of the correction phase vector for the selected observation points. That is, for the selected x observation points, the correction phase calculation unit 27 calculates the correction phase vector for each frequency and calculates the average value of the correction phase vector for each frequency (step S150).

[0139] In this way, the correction phase calculation unit 27 extracts the upper M observation coordinates, and extracts x observation coordinates that are the combination with the smallest phase difference at each frequency among the combinations of x observation coordinates contained in the upper M observation coordinates. Then, the correction phase calculation unit 27 calculates the average value of the phase at each frequency for the extracted x observation coordinates as the correction phase.

[0140] The correction phase calculation unit 27 sets the average value of the calculated correction phase vector as the correction phase for each frequency output to the phase synthesis image generation unit 28. For x observation points, the correction phase calculation unit 27 generates a phase synthesis image using the correction phase (average value of the correction phase vector) calculated for each frequency (step S160). Alternatively, x can be the same value as M.

[0141] Figure 15This is a diagram illustrating the combination of the sets of observation coordinates calculated by the object perspective device in Embodiment 3, and the sum of the Euclidean distances in each combination. Figure 15 In this context, the formula is used to represent the combination of the observation coordinate set L with M=4 and x=3, as well as the sum of the Euclidean distances in each combination.

[0142] Thus, according to Embodiment 3, the object perspective device 10A can use information from multiple observation points in the calculation of the correction phase, and therefore, compared with Embodiments 1 and 2, it can stably calculate the correction phase.

[0143] Here, the hardware structure of the object perspective devices 10A and 10B will be described. Since the object perspective devices 10A and 10B have the same hardware structure, the hardware structure of the object perspective device 10A according to Embodiment 1 will be described below.

[0144] In the object perspective apparatus 10A of Embodiment 1, the orthogonal detector 21, waveform recording unit 22, frequency control unit 23, high-frequency signal generator 24, position control unit 25, power synthesis image generator 26, phase correction calculation unit 27, and phase synthesis image generator 28 are implemented by a processing circuit. The processing circuit can be a processor and memory that execute programs stored in a memory, or it can be dedicated hardware. The processing circuit is also called a control circuit.

[0145] Figure 16 This is a diagram illustrating an example of the structure of the processing circuit in the case where the processing circuit of the object perspective device of Embodiment 1 is implemented by a processor and a memory. Figure 16 The processing circuit 90 shown is a control circuit, having a processor 91 and a memory 92. When the processing circuit 90 is composed of a processor 91 and a memory 92, the functions of the processing circuit 90 are implemented through software, firmware, or a combination of both. The software or firmware is described as a program and stored in the memory 92. In the processing circuit 90, the processor 91 reads and executes the program stored in the memory 92, thereby implementing the various functions. That is, the processing circuit 90 has a memory 92 used to store programs whose result is the execution of the processing of the object perspective device 10A. This program can also be described as a program used to cause the object perspective device 10A to perform the various functions implemented by the processing circuit 90. This program is provided through a storage medium storing the program, or it can be provided through other means such as a communication medium.

[0146] The above procedure can also be described as enabling the object perspective device 10A to perform... Figure 12The processing procedure of steps S10 to S50. That is, the above procedure can also be described as a procedure in which the object perspective device 10A performs the steps of recording received waveform data, generating a power composite image, searching for the coordinates of the maximum reflection intensity, calculating the phase of the correlation vector at the coordinates of the maximum reflection intensity as a correction phase, and generating a phase composite image using the correction phase.

[0147] Here, the processor 91 is, for example, a CPU (Central Processing Unit), processing device, arithmetic device, microprocessor, microcomputer, or DSP (Digital Signal Processor). Furthermore, the memory 92 is, for example, non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable Memory), magnetic disks, floppy disks, optical disks, high-density disks, mini-disks, or DVDs (Digital Versatile Discs).

[0148] Figure 17 This is a diagram showing an example of the processing circuit in the case where the object perspective device of Embodiment 1 is configured with dedicated hardware. Figure 17 The processing circuit 93 shown may be a single circuit, a composite circuit, a programmable processor, a parallel programmable processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. The processing circuit 93 may also be partially implemented in dedicated hardware and partially implemented in software or firmware. Thus, the processing circuit 93 can implement the aforementioned functions using dedicated hardware, software, firmware, or a combination thereof.

[0149] The structure shown in the above embodiments is an example that can be combined with other known technologies, and the embodiments can be combined with each other. Furthermore, a part of the structure can be omitted or modified without departing from the spirit of the subject.

[0150] Label Explanation

[0151] 1A-1C: Scattering point; 2A-2C: Observation point; 10A, 10B: Object perspective device; 11: Transmitting antenna; 12: Receiving antenna; 21: Orthogonal detector; 22: Waveform recording unit; 23: Frequency control unit; 24: High-frequency signal generation unit; 25: Position control unit; 26: Power synthesis image generation unit; 27: Correction phase calculation unit; 28: Phase synthesis image generation unit; 30: Radio wave scatterer; 31, 32: Mixer; 33: 90-degree phase unit; 41: Memory unit; 42, 43: ADC; 44: Corresponding information; 50: Rotating stage; 51-53: Image; 55: Power synthesis image; 56: Phase synthesis image; 71, 72: Antenna movement path; 90, 93: Processing circuit; 91: Processor; 92: Memory; W: Reflected wave.

Claims

1. An object perspective device, which generates a phase composite image of an object based on reflected waves containing multiple frequencies of radio waves irradiating an object disposed within a measurement area, received while varying the frequency and the position of the transmitting and receiving antennas, wherein the reflected waves are received. The object perspective device has the following features: A phase-combined image generation unit generates a phase-combined image by complex summing each pixel of a plurality of images obtained by imaging reflected waves whose frequencies are the same as those contained in the irradiated radio waves. A power-combined image generation unit generates a power-combined image by combining images of the object at each frequency, based on received waveform data (i.e., waveform data of the reflected wave radiated from a transmitting antenna and reflected by the object and received by a receiving antenna), position data (indicating the positions of the transmitting and receiving antennas relative to the object), and frequency data (i.e., frequency data of the radio waves radiated from the transmitting antenna), using a matched filter imaging method of power combining. The matched filter of the power combining method accumulates a correlation vector representing the correlation between the estimated waveform of the reflected wave and the received waveform data at each pixel. The phase correction calculation unit performs the following processes: searching for the maximum reflection intensity coordinate or a plurality of upper-level observation coordinates representing the maximum reflection intensity in the power-combined image based on the power-combined image, the received waveform data, the position data, and the frequency data; and calculating the phase of the correlation vector at the maximum reflection intensity coordinate or the plurality of upper-level observation coordinates at each frequency as a correction phase to be used in phase correction when performing phase synthesis on the image. The correction phase calculation unit calculates the phase at each frequency of the maximum reflection intensity coordinate as the correction phase, or the correction phase calculation unit calculates the average of the phases at each frequency of the plurality of upper-level observation coordinates as the correction phase. The phase-synthesized image generation unit generates a phase-synthesized image by combining images of the object at each frequency, based on the corrected phase, the received waveform data, the position data, and the frequency data, using an imaging method employing a matched filter that performs complex addition of the correlation vector for each pixel. The object perspective device further includes a position control unit that moves the transmitting antenna and the receiving antenna along a predetermined antenna movement path, which is a circular path that moves in a manner that surrounds the object. Alternatively, the position control unit controls the rotational position of a rotating stage included in the object perspective device, which carries the object and rotates. The change of frequency and transmit / receive antenna position includes: repeating a certain range of frequencies in a stepped manner for the transmit / receive antenna position set by the position control unit.

2. The object perspective device according to claim 1, characterized in that, When generating the phase composite image, the phase composite image generation unit subtracts the correction phase from the phase offset of the correlation vector at each frequency, and performs complex summation on the correlation vector for each pixel.

3. The object perspective device according to claim 1, characterized in that, The correction phase calculation unit extracts multiple observation coordinates from the multiple observation coordinates contained in the upper-level multiple observation coordinates that form the combination with the smallest phase difference for each frequency, and calculates the average value of the phase at each frequency at the extracted multiple observation coordinates as the correction phase.

4. The object perspective device according to any one of claims 1 to 3, characterized in that, The radio waves in question are signals in the Asia-Pacific Hertz to Terahertz bands.

5. A control circuit that generates a phase composite image of an object based on reflected waves containing multiple frequencies of radio waves irradiating an object disposed within a measurement area, which are received while varying the frequency and the position of the transmitting and receiving antennas, wherein the reflected waves are received. The control circuit causes the object perspective device that sees through the object to perform the following processing: A phase composite image is generated by combining multiple images obtained by imaging the reflected waves whose frequencies are the same as those contained in the irradiated radio waves, and by adding a complex number to each pixel of the multiple images. Based on received waveform data (i.e., received waveform data, representing the waveform of the reflected wave radiated from the transmitting antenna and reflected by the object and received by the receiving antenna), position data (representing the positions of the transmitting and receiving antennas relative to the object), and frequency data (i.e., frequency data, representing the frequency of the radio wave radiated from the transmitting antenna), a power-combined image is generated by synthesizing images of the object for each frequency using an imaging method employing a power-combining matched filter. The power-combining matched filter accumulates a correlation vector for each pixel, representing the correlation between the estimated waveform of the reflected wave and the received waveform data. Based on the power-combined image, the received waveform data, the location data, and the frequency data, a maximum reflection intensity coordinate or a plurality of upper-level observation coordinates representing the maximum reflection intensity is searched in the power-combined image. The phase of the correlation vector at the maximum reflection intensity coordinate or the plurality of upper-level observation coordinates is calculated at each frequency as a correction phase used for phase correction during phase synthesis of the image. Alternatively, the correction phase can be calculated as the phase at each frequency of the maximum reflection intensity coordinate, or the average phase at each frequency of the plurality of upper-level observation coordinates can be used as the correction phase. In the process of generating the phase-synthesized image, based on the corrected phase, the received waveform data, the position data, and the frequency data, an imaging method using a matched filter that performs complex addition of the correlation vector for each pixel is used to generate the phase-synthesized image of the object at each frequency. The control circuit further enables the object perspective device to perform the following processes: move the transmitting antenna and the receiving antenna along a predetermined antenna movement path, which is a circular path that moves in a manner that surrounds the object; or control the rotational position of a rotating platform included in the object perspective device, which carries the object and rotates. The change of frequency and position of transmitting and receiving antennas includes: repeating a certain range of frequencies in a stepped manner for a set position of transmitting and receiving antennas.

6. A storage medium storing a program that generates a phase composite image of an object based on reflected waves containing multiple frequencies of radio waves irradiating an object disposed within a measurement area, received while varying the frequency and the positions of transmitting and receiving antennas, wherein the reflected waves are received. The procedure causes the object perspective device that sees the object to perform the following processing: A phase composite image is generated by combining multiple images obtained by imaging the reflected waves whose frequencies are the same as those contained in the irradiated radio waves, and by adding a complex number to each pixel of the multiple images. Based on received waveform data (i.e., received waveform data, representing the waveform of the reflected wave radiated from the transmitting antenna and reflected by the object and received by the receiving antenna), position data (representing the positions of the transmitting and receiving antennas relative to the object), and frequency data (i.e., frequency data, representing the frequency of the radio wave radiated from the transmitting antenna), a power-combined image is generated by synthesizing images of the object for each frequency using an imaging method employing a power-combining matched filter. The power-combining matched filter accumulates a correlation vector for each pixel, representing the correlation between the estimated waveform of the reflected wave and the received waveform data. Based on the power-combined image, the received waveform data, the location data, and the frequency data, a maximum reflection intensity coordinate or a plurality of upper-level observation coordinates representing the maximum reflection intensity is searched in the power-combined image. The phase of the correlation vector at the maximum reflection intensity coordinate or the plurality of upper-level observation coordinates is calculated at each frequency as a correction phase used for phase correction during phase synthesis of the image. Alternatively, the correction phase can be calculated as the phase at each frequency of the maximum reflection intensity coordinate, or the average phase at each frequency of the plurality of upper-level observation coordinates can be used as the correction phase. In the process of generating the phase-synthesized image, based on the corrected phase, the received waveform data, the position data, and the frequency data, an imaging method using a matched filter that performs complex addition of the correlation vector for each pixel is used to generate the phase-synthesized image of the object at each frequency. The procedure causes the object perspective device to further perform the following processes: move the transmitting antenna and the receiving antenna along a predetermined antenna movement path, which is a circular path that moves in a manner that surrounds the object; or control the rotational position of a rotating stage included in the object perspective device, which carries and rotates the object. The change of frequency and position of transmitting and receiving antennas includes: repeating a certain range of frequencies in a stepped manner for a set position of transmitting and receiving antennas.

7. A method for perspective analysis of an object, comprising generating a phase composite image of the object based on reflected waves containing multiple frequencies of radio waves irradiating an object disposed within a measurement area, received while varying the frequency and the position of the transmitting and receiving antennas, wherein the reflected waves are received. The object perspective method includes: In the first image generation step, the control circuit performs complex summation on each pixel of a plurality of images obtained by imaging the reflected waves whose frequencies are the same as those contained in the irradiated radio waves, thereby generating a phase composite image composed of the plurality of images. In the second image generation step, the control circuit generates a power-combined image by synthesizing images of the object at each frequency using a matched filter imaging method with a power combining approach. This image is based on received waveform data (the waveform of the reflected wave radiated from the transmitting antenna and reflected by the object and received by the receiving antenna), position data (indicating the positions of the transmitting and receiving antennas relative to the object), frequency data (indicating the frequency of the radio waves radiated from the transmitting antenna), and positional data (indicating the positions of the transmitting and receiving antennas relative to the object). The calculation step involves the control circuit performing the following processes: searching for the maximum reflection intensity coordinate or multiple upper-level observation coordinates representing the maximum reflection intensity in the power-combined image based on the power-combined image, the received waveform data, the position data, and the frequency data; and calculating the phase of the correlation vector at the maximum reflection intensity coordinate or the multiple upper-level observation coordinates at each frequency as a correction phase used for phase correction during phase synthesis of the image. Specifically, the control circuit calculates the phase at each frequency of the maximum reflection intensity coordinate as the correction phase, or the control circuit calculates the average of the phases at each frequency of the multiple upper-level observation coordinates as the correction phase. In the first image generation step, the control circuit generates a phase-synthesized image by combining the images of the object at each frequency, based on the corrected phase, the received waveform data, the position data, and the frequency data, using an imaging method employing a matched filter that performs complex addition of the correlation vector for each pixel. The object perspective method further includes: The transmitting antenna and the receiving antenna are moved along a predetermined antenna movement path, which is a circular path that moves in a manner that surrounds the object; alternatively, the rotational position of the turntable that carries and rotates the object is controlled. The change of frequency and position of transmitting and receiving antennas includes: repeating a certain range of frequencies in a stepped manner for a set position of transmitting and receiving antennas.

Images