JPH1165406A - Device and method for observing circumferential scanning type hologram - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a dead angle, to realize a 360 deg. visual field angle and to evaluate the propagation of radio waves and sound waves at a real time by using a fixed sensor and a scanning sensor, which conducts a circumferential scanning and obtaining the interference of the signals received by both of the sensors while moving the scanning sensor. SOLUTION: A radiated wave motion is made to a first received signal by receiving the radiated wave motion with a first sensor while the first sensor is scanned on the circumference. A radiated wave motion is made to a second received signal by receiving the radiated wave motion with a second sensor located at a position without changing to the center of the circumference. Then, the both received signals are interferred with each other to obtain interferred signals and the interferred signals are detected to obtain the measured data at each point. That is, as represented by the expression, a point on the circumference is represented by a rotational angle ϕ, the radius of the circle is called r, the imaginary unit is represented by j, the circular constant is called π, the rotational angle of the center position is called ϕ', the wavelength of the radiated wave motion is called λ, the incident angle of the radiated wave motion is called θ and a weighting function is called W(ϕ). Based on the measured data E2 (r, ϕ) at each point, an evaluation function V(ϕ') is calculated and a bearing ϕ' of the radiated wave motion is estimated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for observing radio wave holograms and sound wave holograms, and more particularly, to an observation method and apparatus capable of observing without blind spots.

[0002]

2. Description of the Related Art Radio waves and sound waves are also waves, so that holograms can be observed in the same way as light, and are used for visualizing wave source images and specifying noise (unwanted electromagnetic wave radiation, noise, etc.) sources. ing. The present inventor has disclosed in, for example,
-201459 and JP-A-9-134113, observed a radio wave hologram and a sound wave hologram,
A method and an apparatus for obtaining a wave field intensity and a wave source image are disclosed. FIG. 1 is a diagram showing an outline of a hologram observation method disclosed in Japanese Patent Application Laid-Open No. 8-201459. A rectangular hologram observation surface 92 is set at a position distant from the observation target (wave source) 91, and a scanning sensor 93 that moves two-dimensionally in the hologram observation surface 92 is used to observe each point of the hologram observation surface 92. A radio wave or a sound wave of a predetermined observation frequency from the target 91 is detected. Further, a fixed sensor 94 is provided separately from the scanning sensor 93, and the fixed sensor 9 is provided.
4 also detects radio waves and sound waves of the above-mentioned observation frequency from the observation target. Interferor 95 allows both sensors 93, 94
And the signal after the interference is detected by the detector 96. Then, the hologram observation surface 9 of the scanning sensor 93
2, the detected signal (a signal representing the correlation between the signals from both sensors 93 and 94, ie, a signal representing the hologram intensity at the position of the scanning sensor 93 in the hologram observation plane 92). ) Is stored in the memory 97. When the observation at all observation points on the hologram observation surface 92 is completed, the data is read from the memory 97, and the hologram image is reproduced by the image regenerator 98.

[0003]

However, in the above-described conventional hologram observation method, since the hologram is observed by plane scanning within the hologram observation surface, radio waves and sound waves arriving from behind the hologram observation surface are observed. Can not do. In addition, since it is difficult to observe radio waves and sound waves that are extremely obliquely incident on the hologram observation surface, the viewing angle is actually about 120 ° and the remaining 240 ° is a blind spot. However, there is a problem that the observation is restricted. For example, when an observation target is arranged at one corner of a room such as an anechoic chamber and a hologram observation device is arranged at a corner facing the observation target, it is necessary to have such a relatively narrow viewing angle. Observations can be made. However, when observing outdoors, it is not possible to assume that the direction of the radio wave or sound wave of the object to be observed is only the forward direction. Will occur.

Further, in the case of the conventional hologram observation method,
Since the hologram image is reproduced after acquiring data of all observation points in the hologram observation plane, there is also a problem that the observation lacks real-time property.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hologram observation method and apparatus capable of evaluating the propagation of radio waves and sound waves in real time without having a blind spot and capable of making the entire 360 ° a viewing angle. It is in.

[0006]

A hologram observation method according to the present invention is a hologram observation method for reproducing a hologram by measuring a radiation wave from an object to be observed. The first sensor receives the radiation wave as a first reception signal, and the second sensor located at a position that does not change with respect to the center of the circumference receives the radiation wave as a second reception signal. An interference signal is obtained by causing the received signal and the second received signal to interfere with each other, and the interference signal is detected to obtain measurement data at each point on the circumference.

In the observation method of the present invention, a point on the circumference is represented by a rotation angle φ, a radius of the circumference is r, an imaginary unit is j, a pi is π, and a center position in a range of a half circumference of the circumference. Is the rotation angle of φ ′, the wavelength of the radiation wave is λ, the incident angle of the radiation wave with respect to the central axis of the circumference is θ, and a predetermined weighting function is W (φ), at each point within a half circumference. Based on the measurement data E _z (r, φ)

[0008]

(Equation 3) To calculate the evaluation function V (φ ′), and calculate the azimuth φ ′ of the radiation wave.
Is desirably estimated. At this time, the peak in the evaluation function V (φ ′) is selected, and the incident angle θ can be calculated from the optimum value of r · sin θ. Alternatively, the evaluation function V (φ ′) may be calculated while changing the direction of the rotation axis of the circumference so that the incident angle θ becomes 90 °.

Further, according to the hologram observation method of the present invention,
Acquisition of measurement data is continuously performed by continuously moving the first sensor on the circumference, and based on the measurement data for half a circle of the measurement data already obtained, the evaluation function V ( It is desirable to continuously calculate φ ′). In this case, it is preferable that the current rotation angle of the first sensor is not included in the half-circle angle range for calculating the evaluation function V (φ ′). Alternatively, an image in the direction of the rotation angle φ ′ may be captured, and this image may be displayed together with a display expressing the calculated evaluation function V (φ ′).

A hologram observation device according to the present invention is a hologram observation device for reproducing a hologram by measuring a radiation wave from an object to be observed. The hologram observation device receives a radiation wave and uses it as a first reception signal. Driving means for scanning the sensor on the circumference, a fixed sensor which is arranged at a position which does not change with respect to the center of the circumference, receives the radiation wave and serves as a second reception signal, And a detector that detects the interference signal and outputs measurement data at each point on the circumference. In this observation device, the trigger timing of the measurement may be determined based on the ID signal extracted from the second received signal, and the level detection for calculating the average signal level from the second received signal may be performed. Means and a level calibrator for calibrating the level of the measurement data based on the average signal level may be provided.

Further, in this observation device, a ring data buffer memory in which measurement data is written at an address corresponding to the circumference and corresponding to the current rotation angle of the scanning sensor,
A point on the circumference is represented by a rotation angle φ, a radius of the circumference is r, an imaginary unit is j, a pi is π, a rotation angle of a center position in a half range of the circumference is φ ′, The wavelength is λ, the incident angle of the radiated wave with respect to the plane formed by the circumference is θ, and a predetermined weighting function is W (φ), and at each point within the above-described half circumference stored in the ring data buffer memory. Measurement data E
_{Based on z} (r, φ),

[0012]

(Equation 4) An evaluation value calculation unit that calculates an evaluation function V (φ ′) by
It is good to have. In this case, it is preferable to provide an offset adding unit that adds a half-turn angle to the current rotation angle of the scanning sensor to obtain a rotation angle φ ′. In addition, a TV camera that is driven to rotate together with the scan sensor by the driving unit while maintaining an angle difference of half a circle with respect to the scan sensor, and a display based on measurement data and a display based on an evaluation function are performed together with an image captured by the TV camera. And a display unit.

Hereinafter, the principle of hologram observation in the present invention will be described. As shown in FIGS. 2 (a) and 2 (b), three-dimensional xyz rectangular coordinates are set, and the observation point P is located at a point on the xy plane at a distance r from the origin O. The observation point P can rotate around the origin O, and the rotation angle of the observation point P measured from the x-axis direction is φ. The zenith angle (incident angle) measured from the z-axis direction of the wave source S is defined as θ. Here, it is assumed that a plane wave from the wave source S is incident on the observation point P.

As shown in FIGS. 2A and 2B, a plane wave in which the magnetic field H travels in the y-axis direction and at an angle of θ with the z-axis is represented by a cylindrical coordinate expression of Maxwell equation. Apply and find the z-axis or E _z component of the electric field E,

[0015]

(Equation 5) Where j is the imaginary unit and J _n is Bessel
The function, k = 2π / λ, λ, is the wavelength of the wave to be observed.

Equation (1) is expressed by using Jacobi's expansion formula,

[0017]

(Equation 6) Can be expanded. Here, the electric field E _z on the circumference with z = 0 is

[0018]

(Equation 7) Becomes Also, the incident angle of the plane wave with respect to the x-axis direction is φ _i
Then, equation (3) becomes

[0019]

(Equation 8) And can be transformed.

In equation (4), A ₀ , θ, φ _i are unknown, and z
It is assumed that only an electric field E _z (r, φ) on a circumference whose distance from the origin O is r on a plane of 0 (xy plane) can be observed. Here, the evaluation function V (φ ′) is defined as follows.

[0021]

(Equation 9) Here, W (φ) is a weight function for the purpose of stabilizing the evaluation function V (φ ′) (reducing the cutting error).

[0022]

(Equation 10) given that,

[0023]

[Equation 11] Holds, that is, a normalized weight function can be obtained.

By substituting equation (4) into equation (5),

[0025]

(Equation 12) Is obtained. In this equation (8), the weighting function W (φ) is
A normalized weight function as shown in the equation, and r ′ = r · s
When in θ, when the φ '= φ _i, the _{V (φ i) = A 0} · sin θ. Also, as is clear from equation (8), r ′ = r · s
'under the conditions of _{= φ i, V (φ'} in θ at Katsu φ) takes a maximum value,

[0026]

(Equation 13) If V (φ ′) is evaluated by taking an arbitrary real number a of 0 <a ≦ 1, and the maximum value is found, θ, A ₀ , and φ _i are respectively

[0027]

[Equation 14] All can be obtained as. A ₀ is sin
This is a correction term of the evaluation amplitude based on θ.

Note that the exponential function term (exp term) of equation (8), that is, the oscillation term of the integrand, is

[0029]

(Equation 15) When r≫λ, “r ′ = r · sin θ and φ ′ = φ
_{In the} case of not " _i ", the value of the equation (8) is almost 0 because it is the integral of the vibration solution. On the other hand, when “r ′ = r · sin θ and φ ′ = φ _i ”, the non-vibration solution e ⁰ = 1, and a peak is given.

Here, the result obtained by confirming the result of equation (8) by computer simulation will be described.

FIG. 3 shows the electric field observed when a total of four wave sources S are placed at φ _i = 45 °, 135 °, 225 °, and 315 °, where A ₀ · sin θ = 1 for each wave source. make use of
The results of the evaluation of equation (8) are shown as follows.
It is a graph shown as an OA (Direction of Arrival: arrival direction) evaluation value. In the graph, the solid line shows the result when θ of all the wave sources was set to 45 °, and the dotted line shows the θ of each wave source.
Is changed from 90 ° to 30 °. In the evaluation of the expression (8), r ′ = r · sin (45 °). Further, r = 100 cm and λ = 15 cm.

As is apparent from FIG. 3, according to the method of the present invention, the directions of a plurality of wave sources can be efficiently and accurately separated. Also, even if the incident angle θ with respect to the z-axis is unknown, it is possible to estimate θ by changing r ′ in equation (8) and looking at the spectrum spread with respect to the peak level and the angle φ. . At this time, since the peak position does not change regardless of θ, for example, when r ′ = r, the angle φ in Expression (8) is used.
It is effective to obtain all the spectra once for all the peaks, and obtain the maximum of the evaluation value only for some peaks in the range of 0 <r ′ ≦ r. Here, the term “spectrum” refers to a graph showing a change in the evaluation value with respect to the rotation angle φ.

Furthermore, the component of the rotation angle φ of the electric field E, that is,

[0034]

[Outside 1] Is also possible. on the circumference of radius r in the plane of z = 0

[0035]

[Outside 2] The ingredients are

[0036]

(Equation 16) As

[0037]

[Equation 17] Then, it can be treated the same as equation (5). However, in this case, it is not necessary to correct the evaluation amplitude by sin θ.

[0038]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a diagram showing a configuration of a circumferential scanning hologram observation apparatus according to an embodiment of the present invention, FIG. 5 is a perspective view showing an example of a configuration of a scanning antenna, and FIG. FIG. 2 is a block diagram illustrating a configuration of a signal processing device portion in the hologram observation device.
Here, the case of observing a radio wave hologram will be described, but a sound wave hologram can also be measured by the same configuration as described below. Since it is a radio hologram, the sensor for detecting the wave of the observation target is an antenna.

This circumferential scanning hologram observing apparatus also includes a fixed antenna 11 and a scanning antenna 12 like the conventional hologram observing apparatus shown in FIG. Radius r above
The scanning antenna is different from the scanning antenna in the conventional observation apparatus in that the scanning is performed by rotating on the circumference of a circle. That is, the scanning antenna 12 performs circumferential scanning.

The observation bench 13 includes a table 14 and a motor 15 mounted on the table 14 for rotating a beam member 16 in a horizontal plane. The scanning antenna 12 is mounted on one end of the beam member 16. ing. At the other end of the beam member 16, a TV (television) camera 17 for photographing the surrounding scene is attached. On the beam member 16, a signal received from the scanning antenna 12 and a T
A directional signal combiner 18 for synthesizing a high-frequency video signal from the V camera 17 is provided. Here, the frequency band of the radio wave to be observed is different from the frequency band of the high-frequency video signal, and even if the received signal and the high-frequency video signal are combined by the directional signal coupler 18, these two signals can be separated later. It has become.

The beam member 16 is moved by one end of the rotating shaft 19 of the motor 15 near a position where the weights of the scanning antenna 12, the TV camera 17 and the directional signal coupler 18 mounted thereon are just balanced. Supported. The scanning antenna 12 is configured such that the beam member 16
Is located at a distance r from the point supported by the
Will orbit along the circumference of. The inside of the rotating shaft 19 is a coaxial line, and the other end of the rotating shaft 19 is provided with a coaxial rotary joint 20, and a signal from the directional signal coupler 18 transmits a signal from the directional signal coupler 18 to the coaxial line in the rotating shaft 19. Through the coaxial rotary joint 20, the coaxial cable 2
1 is drawn out to the outside. The motor 15 also includes a rotation angle sensor, and outputs a signal indicating the rotation angle φ of the rotation shaft 19 from the motor 15. Here, the rotation angle φ of the rotation shaft 19 is the scanning antenna 1 as it is.
2 represents a rotation angle (position angle).

Here, the configuration of the scanning antenna 12 will be described. As is clear from the principles described above, here, we want to observe the z-axis component E _z of the electric field E, as the scanning antenna 12, for example, using a vertical half-wave dipole antenna. The present inventor has disclosed Japanese Patent Application Laid-Open No. 9-15372.
The probe antenna with a reflector disclosed in Japanese Patent Publication No. 5 can be preferably used. FIG.
FIG. 1 is a perspective view showing a scanning antenna 12 using a probe antenna disclosed in Japanese Patent No. 3725.

Assuming that the wavelength of the radio wave to be observed is λ, a rectangular metal reflector 31 having at least one side of 2λ or more is provided at one end of the coaxial cable 32 at substantially the center of the reflector 31 from the rear side. Is inserted upright. The protruding length of the coaxial cable from the reflection plate 31 is about λ / 4, and the outer conductor of the coaxial cable 32 is electrically connected to the reflection plate 31 at the penetrating portion with the reflection plate 31. On the distal end side from the penetrating portion, the outer conductor of the coaxial cable 32 is split into two by a pair of slit portions 34 extending in the protruding direction to form outer conductor pieces 32a and 32b. At the end of the coaxial cable 32, a half-wavelength dipole antenna 33 parallel to the reflection plate 31 is connected so as to be fed centrally.
Specifically, the root of one element 33a of the dipole antenna 33 is connected to the tip of one external conductor piece 32a, and the root of the other element 33b is connected to the tip of the other external conductor piece 32b. Furthermore, coaxial cable 3
Two center conductors 32c are connected to the root of one element 33a. In this scanning antenna 12, one of the outer conductor pieces 32a functions as a quarter-wavelength distributed constant balun to perform balanced-unbalanced conversion. The reflector 31 suppresses the directional gain in the rear direction, and apparently generates a mirror image signal source to improve the gain in the front direction of the antenna.

The coaxial cable 21 from the coaxial rotary joint 20 is input to the distributor 22. The distributor 22
A signal separating the reception signal of the scanning antenna 12 and the high-frequency video signal synthesized by the directional signal coupler 18;
A direct current (DC) power supply 29 is also connected to the distributor 22. The DC power supply 29 is connected to the TV camera 17 and the scanning antenna 1.
2 for supplying a power supply voltage to a preamplifier (not shown). The DC current from the DC power supply 29 is supplied to the coaxial cable 21, the coaxial rotary joint 20,
Is supplied to a directional signal coupler 18 via a coaxial line therein, and is separated by the directional signal coupler 18 so that the scanning antenna 1
2 and the TV camera 17.

The high-frequency video signal component of the signal separated by the distributor 22 is converted to a band-pass filter (BPF) 23.
, And the demodulated output from the demodulator 26 is input to the display unit 27. Among the signals separated by the splitter 22, the reception signal component at the scanning antenna 12 is input to the band-pass filter 24, frequency-restricted to a predetermined observation frequency band, and then signal as the reception signal S _m (f). Input to the processing device 28. Further, the signal received by the fixed antenna 11 is amplified by a preamplifier (not shown) and then input to the band-pass filter 25, where the signal is frequency-limited to the same observation frequency band as the scanning antenna 12 side.
_The signal is input to the signal processing device 28 as _r (f). A signal representing the rotation angle φ of the rotation shaft 19 is also input to the signal processing device 28. The measurement data and the evaluation data are output from the signal processing device 28 to the display unit 27 as described later.

FIG. 6 is a block diagram showing the internal configuration of the signal processing device 28. The signal processor 28 causes the received signal S _r (f) from the fixed antenna 11 and the received signal S _m (f) from the scanning antenna 12 to interfere with each other,

[0047]

(Equation 18)And an output signal from the interferometer 41.
Complex detection and detection signal V _oDetector 42 that outputs (φ)
And the received signal S from the fixed antenna 11_rdemodulate (f)
Average signal level V_RAnd in this received signal
Level that detects the ID (identification) signal of the device and uses it as a measurement trigger
/ ID detector 43 and detection signal V_o(φ) is the average signal level.
Le V_RLevel calibration by dividing by
Level calibrator 44 which outputs the data as data E (r, φ)
Measurement data E (r, r,
φ) is stored in the ring data buffer memory 45.
I have. Where t is a time variable,^*Is the complex conjugate
It represents. Each data in the ring data buffer memory 45
The memory address is assigned to each observation point on the circumference by circumferential scanning.
Therefore, the rotation angle φ of the observation point is
Ring data buffer memo by giving as dress
Access the data corresponding to the rotation angle φ at
Can be The measurement trigger is used for the measurement by the detector 42.
Used to control trigger timing. In addition, interference
The detector 41 and the detector 42 are disclosed in
No. 9-133721 discloses a correlation function measuring device.
In addition, those comprising a multiplier and a vector detector are preferable.
Can be used.

When reproducing a hologram image of a radio wave continuously emitted, it is not necessary to detect an ID signal or the like and use it as a trigger timing for measurement. However, a hologram image of an intermittently emitted radio wave is reproduced. In such a case, it is necessary to perform measurement in accordance with the timing of firing, and for that purpose, an ID signal detected from a received signal is used. As the ID signal, for example, a unique word portion including a known code from a known wireless transmission station is used, or a frequency hop TDMA (Time Division Multiple Access: Time Division Multiple Access) is used.
i Access), it is possible to use switching information of the channel center frequency.

The writing position in the ring data buffer memory 45 is determined by a signal representing the rotation angle φ of the rotating shaft 19. In this circumferential scanning hologram observation apparatus, both sides of the ring data buffer memory 45 are 90 ° (= π / π) around a position (reproduction position φ ′) that is diametrically opposite to the above-described writing position φ on the circumference. 2 rad)
Is read out, and the processing of the above equation (5) is performed to obtain evaluation data V (φ ′). Therefore, an offset adder 46 for calculating the reproduction position φ ′ by adding an offset of ± 180 ° (= ± π rad) to the rotation angle φ, and link data buffer memory 45 for storing data in the range of φ ′ ± 90 °. Evaluation value calculation unit 47 that reads out from the above and performs the processing of equation (5) to calculate the evaluation data V (φ ′)
Are further provided in the signal processing device 28.

Next, the operation of the circumferential scanning hologram observation device will be described.

When the motor 15 is driven, the rotating shaft 19 rotates at a predetermined speed, the beam member 16 also rotates, and the scanning antenna 12 performs a circumferential scan. At this time, the TV camera 17 turns the scanning antenna 12
And rotate to capture the surrounding scene. The current rotation angle φ of the scanning antenna 12 is constantly transmitted from the motor 15 to the signal processing device 28.

The signal received by the scanning antenna 12 passes through the distributor 22 and the band-pass filter 24 and is input to the interferometer 41 as a reception signal S _m (f) whose frequency is limited to a predetermined observation frequency band. Here, f represents the observation frequency. The signal received by the fixed antenna 11 is also similarly frequency-limited via the band-pass filter 25, and the received signal S
_It is input to the interferometer 41 as _r (f). From the interferometer 41,
An interference signal of these two received signals S _m (f) and S _r (f)

[0053]

[Equation 19] And the interference signal is subjected to complex detection by the detector 42 to become a detection signal V _o (φ), and the detection signal V _o (φ)
In level calibrator 44 is calibrated level by an average signal level V _R, the measurements for phi current rotation angle data E (r, φ). The measurement data E (r, φ) is written to an address of the ring data buffer memory 45 corresponding to the current rotation angle φ, and is output to the display unit 27. At the same time, based on the reproduction position φ ′ obtained by calculating an offset of ± 180 ° from the current rotation angle φ, data in the range of the reproduction position φ ′ ± 90 ° is read from the ring data buffer memory 45 and read. The evaluation value calculation unit 47 calculates the evaluation value by performing the processing of the above-described equation (5) based on the obtained data. The calculated evaluation value is output to the display unit 27 as DOA evaluation data V (φ ′). (5)
When performing the processing of the equation,

[0054]

(Equation 20) May be calculated in advance and stored in a memory or the like, and may be read from the memory when actually performing the processing of equation (5).

In the display section 27, the measurement data E (r, φ),
Evaluation data V (φ ′), an image captured by the TV camera 17,
Information about the rotation angle φ and the angle φ ′ that is exactly opposite to the rotation angle φ is displayed in an appropriate combination. In particular, TV camera 1
7, the direction corresponding to the evaluation data V (φ ') matches the imaging direction of the TV camera 17, and the real-time movement of the object on the image with the evaluation data. The association is extremely easy, and it is effective in identifying noise sources and unnecessary electromagnetic radiation sources. If the real-time correspondence with the image captured by the TV camera 17 is not performed, or if the TV camera 17 is not on the reflection side of the scanning antenna 12, the angle range for calculating the evaluation data is set to the rotation angle φ. It is not necessary to be within a range of ± 90 ° about the direction opposite to the above. However, since the rotation angle φ is a position angle at which data writing is currently performed in the ring data buffer memory 45 and is a temporally and accurately discontinuous point, the rotation angle φ falls within an angle range for calculating evaluation data. It is desirable not to include the rotation angle φ. Therefore, when the real-time association with the captured image of the TV camera 17 is not performed, the center angle φ ′ of the angle range for calculating the evaluation data is:

[0056]

(Equation 21) It is possible to select within the range.

In this embodiment, before the hologram observation is started, first, the ring data buffer memory 45 is all cleared to zero, and measurement, writing into the ring data buffer memory 45, reproduction, and calculation of evaluation data are performed. Each process is performed continuously over a plurality of circumferential scans. As a result, the measurement data E (r,
φ) can be displayed, the evaluation data V (φ ′) can be displayed over the entire 360 °, and as long as the scanning antenna 12 keeps rotating,
The evaluation data V (φ ′) is updated as needed.

At least the required angle range, typically 1
After obtaining the evaluation data V (φ ′) for the circumference, the peak is selected, and the zenith angle θ of the wave source is calculated from the optimum value of r ′ in the above equation (8). Instead of optimizing r ′, the table 14 may be operated so that the inclination of θ is given toward the peak direction φ as r = r ′, and the zenith angle θ of the wave source may be obtained.

Next, a display example on the display unit 27 will be described with reference to FIG. FIG. 7A shows an example of a display screen 51 on the display unit 27. On this display screen 51, two graphs of the direct measurement data E (r, φ) and the DOA evaluation value V (φ), and two images of the camera image C and the camera image H are simultaneously displayed. Each graph represents data for one round, with the horizontal axis representing azimuth and the vertical axis representing amplitude, and markers are displayed as bright spots. The marker M in the graph of the direct measurement data indicates the current measurement position, that is, the current azimuth angle φ, and the marker C in the graph of the DOA evaluation value indicates the current reproduction position, that is, the opposite side (the direction of the angle φ ′) of the marker M. Indicates that the marker H is
It shows the peak position specified by the user with respect to the graph of the DOA evaluation value. The camera image C is a television image in the current reproduction direction, and is a moving image that changes as the TV camera 17 moves with the rotation of the beam member 16. As described above, the camera image H is stored in the DOA
This is a camera image showing the position of the marker H specified in the evaluation value graph, and this camera image is an image that is stopped regardless of the movement of the TV camera 17. Then, based on the rotation angle H and the zenith angle θ corresponding to the marker H, the wave source position is marked (shown in black) in the camera image H and displayed.

As shown in FIG. 7B, the measurement data and the DOA evaluation value can be displayed in a radar chart.

[0061]

As described above, according to the present invention, the blind spot is obtained by using the fixed sensor and the scanning sensor that performs circumferential scanning and determining the interference of the signals received by both sensors while moving the scanning sensor. There is an effect that the entire 360 ° can be used as the viewing angle, and the propagation of radio waves and sound waves can be evaluated in real time.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a conventional hologram observation device.

FIGS. 2A and 2B are diagrams showing a relationship between an xyz rectangular coordinate system, a wave source, and observation points.

FIG. 3 is a graph showing a simulation result of a relationship between a rotation angle φ and an evaluation value.

FIG. 4 is a diagram showing a configuration of a circumferential scanning hologram observation device according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating an example of a configuration of a scanning antenna.

FIG. 6 is a block diagram showing a configuration of a signal processing device portion in the device of FIG. 1;

FIGS. 7A and 7B are diagrams showing display examples.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Fixed antenna 12 Scanning antenna 13 Observation bench 14 units 15 Motor 16 Beam member 17 TV camera 18 Directional coupler 19 Rotation axis 20 Coaxial rotary joint 21 Coaxial cable 22 Distributor 23,24,25 Bandpass filter 26 Demodulator 27 Display Unit 28 signal processing device 29 DC power supply 41 interferometer 42 detector 43 level / ID detector 44 level calibrator 45 ring data buffer memory 46 offset adding unit 47 evaluation value calculating unit

Claims (13)

[Claims] 1. A hologram observing method for reproducing a hologram by measuring a radiation wave from an observation object, wherein the first sensor receives the radiation wave by scanning the circumference of the first sensor while scanning the circumference of the first sensor. The radiation wave is received by a second sensor located at a position that does not change with respect to the center of the circumference, and is used as a second reception signal. The first reception signal and the second reception signal are A hologram observation method, comprising: obtaining an interference signal by causing interference; detecting the interference signal; and obtaining measurement data of each point on the circumference. 2. A point on the circumference is represented by a rotation angle φ, a radius of the circumference is r, an imaginary unit is j, a pi is π, and a rotation of a center position of a range of a half circumference of the circumference is performed. The angle is φ ′, the wavelength of the radiation wave is λ, the incident angle of the radiation wave with respect to the center axis (Z-axis) of the circumference is θ, and a predetermined weighting function is W (φ). The measured data E at a certain point
_{Based on z} (r, φ), The hologram observation method according to claim 1, wherein an evaluation function V (φ ′) is calculated by using the equation, and the azimuth φ ′ of the radiation wave is estimated. 3. The hologram observation method according to claim 2, wherein a peak in the evaluation function V (φ ′) is selected, and the incident angle θ is calculated from an optimum value of r · sin θ. 4. The evaluation function V while changing the direction of the rotation axis of the circumference so that the incident angle θ is 90 °.
The hologram observation method according to claim 2, wherein (φ ') is calculated. 5. Acquisition of the measurement data is continuously performed by continuously moving the first sensor on the circumference, and measurement of a half circumference of the measurement data already obtained is performed. The hologram observation method according to claim 2, wherein the evaluation function V (φ ′) is continuously calculated based on data. 6. The hologram observation method according to claim 5, wherein the current rotation angle of the first sensor is not included in the half-circle angle range for calculating the evaluation function V (φ ′). 7. An image in the direction of the rotation angle φ ′ is taken,
The hologram observation method according to claim 5, wherein the image is displayed together with a display representing the calculated evaluation function V (φ ′). 8. A hologram observing apparatus for reproducing a hologram by measuring a radiation wave from an observation target, comprising: a scanning sensor that receives the radiation wave and serves as a first reception signal; Driving means for scanning on the above, a fixed sensor arranged at a position that does not change with respect to the center of the circumference, receiving the radiation wave and setting it as a second reception signal; 2. A hologram observation apparatus, comprising: an interferometer that outputs an interference signal by causing the received signals to interfere with each other; and a detector that detects the interference signal and outputs measurement data at each point on the circumference. 9. An ID extracted from the second received signal
9. The hologram observation device according to claim 8, wherein a measurement trigger timing is determined based on the signal. 10. The apparatus according to claim 8, further comprising: a level detecting means for calculating an average signal level from the second received signal; and a level calibrator for calibrating the level of the measurement data based on the average signal level. The hologram observation device according to the above. 11. A ring data buffer memory in which the measurement data is written at an address corresponding to a current rotation angle of the scan sensor corresponding to the circumference, and a point on the circumference is represented by a rotation angle φ. The radius of the circumference is r, the imaginary unit is j, the pi is π, the rotation angle of the center position of the half range of the circumference is φ ′, the wavelength of the radiation wave is λ, the central axis of the circumference , The angle of incidence of the radiation wave with respect to θ, the predetermined weighting function as W (φ), and the measurement data E _z (r) at each point within the half circumference stored in the ring data buffer memory. , φ) based on An evaluation value calculation unit that calculates an evaluation function V (φ ′) by
The hologram observation device according to any one of claims 8 to 10, further comprising: 12. The hologram observation apparatus according to claim 11, further comprising an offset adding unit that adds an angle of a half turn to a current rotation angle of the scanning sensor to obtain the rotation angle φ ′. 13. A TV camera which is driven to rotate together with the scanning sensor by the driving means while maintaining an angle difference of a half circle with respect to the scanning sensor, and a display based on the measurement data together with an image taken by the TV camera. The hologram observation device according to claim 12, further comprising: a display unit that performs display based on the evaluation function.