JPH01113685A - Object detecting method and apparatus - Google Patents

Abstract

PURPOSE:To improve a resolution in the horizontal direction and thereby to detect the existence of an object to be detected, exactly and highly accurately, by a method wherein a synthetic aperture processing wherein an amplitude value on another hyperbola is added is applied to a reflected wave obtained in a hyperbolic form. CONSTITUTION:An electromagnetic wave emitted into the ground from transmission antenna 2 and reflected therefrom is caught by an antenna 6, processed by a sampling device 7 and then delivered to a computing unit 15. It is digitized in the unit 15, divided at each certain time and converted into a frequency region in a frequency analysis element 15a, and a power spectrum is found therefrom. Next, a spectral frequency fp, a direct-current component ratio Rdc and a half-width W are determined, an unnecessary reflected wave is removed, and an observation signal and scanned section data are outputted to a display device 10. The computing unit 15 is equipped with a multi-section processing element 15b and a synthetic aperture processing element 15c. By this constitution, a resolution in the horizontal direction is improved, and the existence of an object to be detected is detected exactly and highly accurately.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Field of Industrial Application) This invention detects invisible objects such as underground objects by transmitting electromagnetic waves and receiving reflected waves from objects to be detected. The present invention relates to a method and device for detecting objects.

(Prior Art) FIG. 1 shows a schematic example of a measurement system for detecting underground objects as objects to be detected using conventional electromagnetic waves. The electric i4 lus sent from the no 4 lus generator 1 is sent to the transmitting antenna 2, and electromagnetic waves are radiated into the ground. The radiated electromagnetic waves are reflected underground and through different electrical constants and are sent to the receiving antenna 6. (In an actual measuring device, the transmitting and receiving antennas are combined into one device. This is referred to as the antenna device 14.) Next, after passing through the sampling device 7, it is sent to the calculation section 9, and the calculation result is displayed. An example of an observation signal displayed on the device 10 and incident on the receiving antenna 6 directly above the buried pipe 5 is shown in FIG. 2. In FIG. 2, the horizontal axis is expressed in units of time; To measure depth, it is necessary to convert it into distance. Therefore, it is necessary to calculate the underground radio wave propagation velocity V. Ma is given by the following formula.

Here, C is the speed of electromagnetic waves in vacuum, 1. is the dielectric constant of . (Therefore, it is necessary to measure e of ± at the measurement site. - 83 on the ground for boat fishing is 4 to 20.) The horizontal axis in Figure 2 is the reciprocating speed of electromagnetic waves between the ground surface and the object. Therefore, the depth is given by the following equation.

Here, T is the round trip time of electromagnetic waves.

In actual measurements, the antenna device 14 housing the transmitting antenna 2 and the receiving antenna 6 is scanned in the direction of the arrow 105 shown in FIG. 9 to memorize it. After the scanning is completed, the arithmetic unit 9 converts (2) the depth into the depth, and then, as shown in Figure 3, the horizontal axis is the scanning distance and the vertical axis is the depth, and the observation signals are collected. They are arranged in order, and furthermore, a ground plane image is formed which is differentiated in stages depending on the magnitude of the amplitude (usually by color). FIG. 3 is an example of a ground cross-sectional view displayed on the display device 10 in FIG. Therefore, A- is calculated with a rate of 16).
The observed signal in FIG. 2 corresponds to the area A--A in FIG. 3. Third
In the ground cross-section shown in the figure, the amplitude of each observation signal is 30 m.
Time positions that are greater than or equal to V are indicated by diagonal lines, and time positions that are less than that are indicated by white. t, 6.30 mV is the minimum discrimination amplitude of the observation signal of 1 min.

In order to distinguish the reflected wave from an object (hereinafter referred to as the detected object) K such as a buried pipe or a layer of water from an observation signal that is a superposition of various reflected waves, it is conventional to calculate the amplitude of the observation signal. Large and small were the criteria for identification. For example, “Applied Science Center
Newsletter J 1it-42, December 1975r
Applied Science Center for
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75 mm Minimum discrimination width 1 mi as shown in Figure 2
The reflected waveform II with an amplitude larger than n has been identified as the reflected wave from the object to be detected. (Waveform 12 in the same figure is a ground surface reflected wave) (Problem to be solved by the invention) However, in the conventional method and apparatus described above, for example, ':6
'ms< As shown in Fig. 3, if there is a factor in the ground that strongly reflects the electrode waves, such as a stone 4, other than the object to be detected, there will be multiple reflections and・Naki 8 appears. It has been extremely difficult to identify the reflected waves from the object to be detected among these multiple reflectors.

Also, the tai waves radiated from the antenna spread to some extent)
When there is a certain roundness, the reflected wave from an object has a hyperbolic no-shape in the underground m-plane map. For this reason, if the buried pipes are buried close together, such as in the case of JL with 3 rows and 3 layers, these hyperbolic comrades will overlap, resulting in a disadvantage that the resolution in the horizontal direction will be significantly impaired.9. This invention was made in view of the above circumstances, and its purpose is to:
The object to be detected can be detected accurately to highly accurate, and in particular, the reflected wave obtained as a hyperbolic shape of the object to be detected can be subjected to synthetic aperture processing t-m to improve the resolution H in the horizontal direction. There are four ways to recognize objects that can be used and how to connect them.

[Structure of the invention]

(Means for solving the problem) In order to solve the above problem, the object detection method of the present invention converts the reflected signal divided by time into the frequency domain to obtain the spectral distribution, and Only the observation signal from the detected object is extracted from the f parameter value. This observation signal is subjected to a synthetic aperture process that calculates the hyperbolic shape of the corresponding vertex of the earth surface and adds the calculated waveform amplitude on the hyperbola to the amplitude of the hyperbolic vertex.

By applying synthetic aperture processing to each of the reflected waves obtained as multi-sectional information, horizontal resolution can also be improved even when the detected object is a buried pipe with a linear structure. It is possible to detect objects to be detected. Further, the object detection device of the present invention transmits an electromagnetic wave and receives a reflected wave of the electromagnetic wave from an object as an observation signal.
a receiving means; a sampling means for sampling the observed signal; a signal dividing means for dividing the signal f sampled by the sampling means at predetermined time intervals after A7'D conversion; Means for converting into a domain and calculating a vector distribution: Reading meter values of the spectral distribution such as spectral peak frequency f1 DC component ratio R6° and half value width W from the calculated spectral distribution, and calculating the parameter Among the values, the spectral frequency jp is within a predetermined frequency range, and the DC component ratio R is within a predetermined DC component ratio range.
means for extracting only the observation signal from the detected object by removing, as unnecessary reflected waves, observation signals having respective values other than di and the half-width W within a predetermined half-width range; The observation signal extracted by the means for extracting only the observation signal from the detected object corresponds to (X
means for calculating a hyperbolic shape having a vertex at 0tZ,);
The calculated waveform amplitude with the hyperbola is the vertex of the hyperbola (X
a synthetic aperture processing means comprising a means for adding the synthetic aperture processed observation signal to the amplitude of the detected object; It consists of

Furthermore, the object detection device of the present invention captures a plurality of observation signals from the object as multi-section information, performs a correlation calculation between these multi-section information, and extracts only the observation signals from the detected object having a linear structure. By including a means for performing synthetic aperture processing on each point on the earth surface to which these extracted observation signals correspond, horizontal resolution can be achieved even for a detected object having a linear structure. It can be improved.

(Operation) The object detection method and device of the present invention improve horizontal resolution by performing synthetic aperture processing in which amplitude values on other hyperbolas are added to reflected waves obtained as hyperbolic shapes. This can also be done by applying synthetic aperture processing to the reflected waves from the linear conduit, which has a linear structure obtained as multi-sectional information, so that the horizontal direction of the electromagnetic waves radiated from the antenna It is possible to emphasize the signal amplitude at the buried position of the object to be detected by inversely utilizing the spread of the object, and it is possible to detect the object with high reliability.

(Example) An example of the present invention will be described below with reference to the drawings, after frequency analysis is performed on an observation signal obtained as a superposition of various reflected waves, targeting an underground object, such as an underground pipe, as a detected object. Although it is possible to improve the resolution in the horizontal direction by extracting only the reflected waves from the object to be detected and subjecting them to synthetic aperture processing, for convenience of explanation, the following explanation will start from frequency analysis.

1. Method for detecting objects to be detected From an observation signal obtained as a superposition of various reflected waves underground, unnecessary reflected waves are removed from the observation signal using information in the frequency domain of the signal, and only the reflected waves from the object to be detected are detected. Detecting the object to be detected will be described in detail below.

FIG. 4 is a flowchart shown to explain the object detection method according to the present invention. The explanation will be given below according to this flowchart.

Obtaining Observation Signals The steps up to receiving observation signals are based on the principle of the Norsleder method, similar to the conventional technique shown in FIG.

First, electricity/Grus is sent from the mother Lus generator to the transmitting antenna. The transmitting antenna converts the sent electrical pulses into electromagnetic waves and radiates them underground. The radiated electromagnetic waves are reflected by objects that have different electrical constants, such as permittivity, than those underground, and are captured by a receiving antenna.

The receiving antenna converts the reflected electromagnetic waves back into electrical signals, which are then sampled by a sampling device, resulting in an observation signal. An example of the observation signal is shown in FIG. Then, by scanning the transmitting antenna and the receiving antenna in one direction, a ground cross-section along the scanning direction is formed. Specifically, by moving the transmitting antenna and the receiving antenna in one direction, an observation signal map can be formed every 2 cm of moving distance.

The observed signal is a superposition of reflected waves at all discontinuities underground. Therefore, the reflected wave from the detected object is also superimposed on one of the time positions of the observation signal. Therefore, first, this observation signal is divided into certain time intervals. As a division method, there is the following 2M method.

(1) Fixed time division The observation signal is divided into a fixed time width Δt.

(2) Zero-cross division The observed signal is divided into periods equivalent to one cycle using the zero-cross method.

In this embodiment, an example will be described in which the zero-crossing method is used to divide the data into periods corresponding to one cycle.

The above-mentioned FIG. 5 is an example of the observed signal obtained by the Stellar fs1 in FIG. 4 and the waveform division by the zero-crossing method in the Stellar 76S2. The sections indicated by the arrows in FIG. 5 are time intervals equivalent to one period according to the zero-crossing method, and the waveform number is displayed for each divided waveform. Here, an example in which the waveform Nol is separated is shown in the upper part of FIG.

Conversion to the frequency domain The separated waveform is converted to the frequency domain using FFT (high-speed y-transform) processing in the waveform analyzer to obtain the vector distribution. (Stella'fS3) (lower part of Figure 6) To read the characteristics, find the maximum intensity (peak) vector from the obtained spectral distribution, and calculate the p vector intensity for that spectral frequency (spectral peak frequency) f, the DC component intensity "da". and the half-value p width W. (Step 84) Calculate the DC component ratio Rdc Furthermore, the DC component ratio Rdc (DC component intensity l, . of
(ratio to vector peak intensity!) is calculated using the following formula. (Step 86) Rdc=Idc/p(3) The upper part of Figure 6 shows the waveform separated from the observed signal, and the lower part shows the spectral distribution diagram of the separated waveform, as well as the peak frequency f and spectrum distribution of the separated waveform. Indicates the strength, DC component strength!, and half-width W.
da did.

A process beyond removing unnecessary reflected waves is performed on all divided waveforms of the observed signal (
Step 83. J4, 8B), and the resulting spectrum peak frequency f9, DC component ratio Rde, and half-width W, using the characteristics shown in Figs. 7 and 8, 'p
l < fp < fp2 # Rdc, (R6゜(R
,,,W, (W(The divided waveforms having values other than W2 are treated as unnecessary reflected waves and are removed.

Here, FIGS. 7 and 8 show the 'p-Rdc t' of various divided waveforms derived from observation signals obtained through numerous experiments.
It is a graph showing fp-W distribution. The black circles in the figure are the characteristics of waves reflected by the pipe, and the white circles are the characteristics of unnecessary reflected waves. The characteristics of the wave reflected by the pipe clearly fall within a certain range, namely fp, 〈fp＜fp2゜”dcl 〈”da＜
Rdc2 e It can be seen that the distribution is concentrated in the range of Wl < W < W2 e / 1 * /, 2 p
Table 1 shows an example of the value of "del '"da2 #Wl*W2.

Table 1 Note that the divided waveform includes the center frequency fp and the DC component ratio R6.
There are multiple waveforms that satisfy any of the filtering conditions of ゜, half-width W, but as shown in Table 2, Publication 2 that simultaneously satisfies the three conditions among the observed signals is the divided waveform shown in Figure 5. Center frequency f, DC component ratio “d” calculated for each
a' indicates the value of the half width W.

Table 2 Antenna Scanning Distance If the above-mentioned signal processing is applied to all the observation signals recorded every two lessons, only the reflected waves from the buried pipes can be extracted. The observation signal processed by the above method is
- Scanning distance, vertical - The cross-sectional image reconstructed in the one-time coordinate system is
Shown in Figure 0. The waveform corresponding to the position A-A in FIG. 10 is shown in FIG. It is possible to detect.

Note that the boundary conditions shown in Table IK are values specific to the object to be detected (in this example, the boundary condition values are shown when the buried object is a steel pipe), so in the case of other buried objects, the boundaries shown in Table IK The value of the condition changes. Therefore, if the object to be detected is another object (for example, a vinyl chloride pipe, a cavity, a stratum, etc.),
Furthermore, not only objects buried underground but also objects in radio wave transmission media (for example, steel frames in concrete, cracks, etc.), the characteristics of the waves reflected by the object to be detected (fp t Rdc, W
), the object to be detected can be detected by the present invention.

In addition, depending on the burial situation, the above three parameters (
f9. Rdc, W), one characteristic value or a combination of two characteristic values (for example, jp-R, c.

f, -W), it is also possible to extract the reflected waves from the buried pipe.

Multi-section processing ゛In the above-mentioned embodiment, the arithmetic processing in the Stella f86 of Fig. 4 was explained as a process of extracting the reflected waves of the detected object without considering the length and shape of the object (Step 86m of Fig. 4A). If the object to be detected is a buried pipe with a straight structure, after extracting the reflected wave from the object to be detected (step 86m)
The detection accuracy can be improved by performing a correlation calculation on the multi-section information collected in the direction perpendicular to the direction in which the pipeline is buried (step 56b in FIG. 4B).

A method of processing multi-section information will be explained below.

As shown in FIG. 11, the transmitting antenna and the receiving antenna are moved parallel to the antenna scanning line in the scanning direction indicated by the arrow K, and a plurality of ground plane information is recorded. If the object to be detected is a buried pipe 5 with a linear structure perpendicular to the antenna scanning direction, each of the plurality of reflected waves is signal-processed, and as a result, for example, from the measurement cross section 1 to the measurement cross section n in FIG. A plurality of corresponding cross-sectional views can be obtained.

In this way, from the multi-sectional information obtained through signal processing, waveforms existing at the same horizontal and vertical positions are recognized as reflected waves from the buried pipe 5 having a linear structure, and other waveforms are removed. As a result of performing the correlation calculation of such multi-sectional information, a sectional view as shown in FIG. 10 shown earlier can be obtained.

Synthetic Aperture Processing As shown in FIG. 10, the reflected wave from the object to be detected has a hyperbolic shape. This is because the electromagnetic waves radiated from the antenna spread out at a certain angle. The pattern is shown in Fig. 13. If the distance between the antenna and the detected object is L, and the detected object and the antenna have a relative positional relationship as shown in Fig. 13, at the antenna position It is observed as if the detected object were present at the point. If the antenna device 14 scans in the direction of the arrow in FIG. 13, the distance between the antenna and the object to be detected will be small, and the round trip time T of the electromagnetic waves will be short. Then, the reflected wave obtained when the antenna device 14 is at the point X0 directly above the detected object becomes the apex of the hyperbolic shape described above.

Therefore, in the ground profile, the group of reflected waves from the detected object has a hyperbolic shape, and the resolution in the horizontal direction is significantly impaired. Therefore, it is effective to perform synthetic aperture processing on the ground plane information processed by the method described above in order to improve the resolution in the horizontal direction. For this reason, in the arithmetic processing (step 3g), a synthetic aperture processing step (86c) is performed as shown in FIG. 4c, following the Stella 7" (86m) for extracting the reflected wave from the object to be detected.

Figures 1 and 4 show diagrams of the principle of synthetic aperture processing. In the figure, the two axes are the ground surface X axis and the depth direction.

placed on top. Therefore, in order to obtain an image of the detected object at the (Xo, Zo) point, (4) the waveform value on the hole should be added to the waveform value at the (Xo, Zo) point, and as a result, (Xo, Zo) The amplitude of the point grows.

In reality, the reflected waveform oscillates by the reflection wavelength ΔL from the 2nd position oc, (x 0#Z) z=z0~z0+
It will grow at ΔL. If the above processing is performed at all coordinate positions (x p z >) on the ground cross-section, if (X#Z) = (X, tZo), then the image with the maximum vibration will be (Xo, Zo ) obtained at the point.

An example in which this process is applied to the ground cross-sectional view shown in Figure 10 is shown in the first example.
It is shown in Figure 5. In this way, the resolution in the horizontal direction can be improved in this process.

Display of processing results The scanning cross-sectional data and the data subjected to multiple processing according to the present invention are output and displayed on the display device 10.

The above synthetic aperture processing (step 56c) can also be performed when the object to be detected is an underground pipe having a linear structure. In this case, as shown in Figure 4D, the extraction of the opposite wave by the object to be detected is performed multiple times in parallel to the direction perpendicular to the direction in which the pipeline is buried, and the collected multi-sectional information is perform correlation calculation (step 56b).
, Finally, synthetic aperture processing is performed on the results of each correlation calculation corresponding to each section information (step, y' S e c
) It is possible to improve the resolution in the horizontal direction, especially for buried pipes with a linear structure. Incidentally, each step 86a, S6b, and S6a shown in FIG. 4D is the same as that explained in FIGS. 4A to 4C, and individual explanations will be omitted.

2. Detected object detection device In order to carry out the object detection method of the present invention described above,
An embodiment of the object detection device will be described below.

FIG. 16 is a block diagram showing an outline of an embodiment of the object detection device according to the present invention, when an underground object is to be detected. In Figure 16, 1 is a pulse generator that generates a high-output impulse (monopulse) signal, and 2 is a wide-band frequency characteristic that converts the nine-noise signal sent from the pulse generator into electromagnetic waves and radiates them into the ground. 3 is on the ground surface, 4 is underground, 5 is a buried pipe, and 6 is a receiving antenna with broadband frequency characteristics that captures electromagnetic waves that have hit and reflected from the object to be detected and converts them into electrical signals. In the example, the antenna is divided into transmitter and receiver.
An integrated transmitter/receiver antenna can also be applied to the present invention. ), 14
1 is an antenna device equipped with a transmitting antenna 2 and 7 receiving antennas V; 7 is a sampling device for sampling the signal sent from the receiving antenna; 1
Reference numeral 5 denotes a computing unit capable of FFT (Fast Fourier Transform) processing, which divides the observation signal into certain time intervals in this apparatus and performs FFT processing on each divided waveform, as will be described later. 10 is a display device.

Next, the operation of the object detection device of the present invention will be explained.

A broadband transmitting antenna 2 and a receiving antenna 6 are set near the ground surface, and high output electricity, p
Antenna 2 that transmits electromagnetic waves by transmitting 4 rus
radiates into the ground. The electromagnetic waves propagate underground 4 and are reflected by hitting various objects having different electrical constants such as permittivity. These reflected electromagnetic waves are captured again by the receiving antenna 6 and converted into electrical signals. The converted signal is sampled by the sampling device 1 and sent to the combination unit 15 as an observation signal. The computing unit 15 includes, for example, a frequency analysis section 15m as shown in FIG. 16A. The frequency analysis section 15m first converts the observation signal, which is an analog signal, into a digital signal. Then, this digitized observation signal is divided at certain time intervals. Here, a division method corresponding to one period based on the zero-crossing method is adopted.

(b) This divided signal is converted into the frequency domain by FFT (Fast Fourier Transform) processing within the frequency analysis section 15. Here, a worth vector indicating the magnitude of energy of each frequency component is obtained.

(c) The maximum intensity (
Look at the spectrum of the peak) and find its spectral frequency (spectral frequency)! 9. DC component ratio Rdc (
(see formula (3)), the half width W is calculated.

(d) Next, the unnecessary reflected waves described in the above-mentioned section 1. Object detection method are removed. That is, the fpl Rdc and WO values calculated in the process (c) are fpl
<Z p < Zp 2 e Re 1 < Rc <
If it is within the range of Rc2 e Wl<W<W2, the divided waveform is determined to be a reflected wave from the buried pipe. If it is outside the range, the divided waveform is removed as an unnecessary reflected wave.

(.) Observation signals and scanning section data from which unnecessary reflected waves have been removed are displayed on a display device 1o shown in FIG. Further, as shown in FIG. 16B, the computing unit 15 is composed of a frequency analysis section 15m and a multi-section correlation processing section isb. In this configuration, the multi-section correlation processing section 15b performs a correlation calculation on the plurality of section information obtained by the frequency analysis section 15, and the waveforms existing at the same horizontal and vertical positions are calculated from the signal-processed multi-section information. can be recognized as a reflected wave from a buried pipe with a straight structure, and other waveforms can be removed. As shown in FIG. 16C, the computing unit 15 of the present invention is comprised of a frequency analysis section 15a and a synthetic aperture processing section 15c. The reflected wave from the detected object 5 obtained by the frequency analysis section 15a has a hyperbolic shape, and when buried pipes are close to each other, the hyperbolic waves overlap, resulting in a significant loss of resolution in the horizontal direction. Therefore, by adding the amplitude value of the waveform existing in the hyperbolic shape to the amplitude value of the waveform existing at the apex in the synthetic aperture processing section 15e, an image with the maximum amplitude can be obtained at the apex, and the horizontal resolution can be improved. It can be improved.

Furthermore, the computing unit 15 of the present invention is composed of a frequency analysis section 15m, a multi-section processing section 11b, and a synthetic aperture processing section 15e, as shown in FIG. 16D. The object to be detected has a linear structure. In the case of underground pipes, the multi-section correlation processing unit 15b performs correlation calculations on the multiple cross-sectional information obtained by the frequency analysis unit 15g to remove reflected waves other than the reflected waves from the buried pipes with a linear structure. After that, a synthetic aperture processing section 15e performs synthetic aperture processing on the obtained reflected waves.

As a result, it is possible to obtain a cross-sectional image with improved horizontal resolution even for underground pipes having a linear structure.

As described above, by using the cross-sectional view according to the present invention, the existence of a buried pipe and its position can be clearly recognized.

Furthermore, even if electromagnetic waves are severely attenuated underground and reflected waves from a pipe cannot be identified in the time domain from observed signals, it is possible to identify them with high accuracy and high resolution by using the method described above. An embodiment has been described in which this invention is applied to underground buried object detection. The presence of the target buried object can be detected even if the objects are close to each other.

In addition, this method can be applied to underground detection such as cavity and strata exploration, invisible object detection such as reinforcing bars in concrete and cavity exploration, and aerial detection to recognition of flying objects. It is.

〔Effect of the invention〕

Even if the underground attenuation rate of electromagnetic waves is large and the reflected waveform from the target buried object cannot be identified using time-domain amplitude information, the amplitude of unnecessary reflected waves from stones etc., for example, is large. Even when reflected waves from a target buried object cannot be distinguished, or even when a plurality of objects are close to each other, the presence of the target object to be detected can be detected appropriately and with high precision.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating a conventional object detection method and device; FIG. 2 is a waveform diagram showing an example of an observation signal input to the calculation unit shown in FIG. 1; FIG. A diagram showing cross-sectional images obtained corresponding to different underground objects displayed on the display unit when the antenna device is scanned in the direction of the arrow shown in FIG. 1; FIG. 4 is an object of the present invention. A flowchart for explaining each step of the detection method and the operation of the object detection device; Figures 4A to 4D are flowcharts showing the different calculation contents of the calculation processing stages shown in Figure 4; Figure 5 is a flowchart for explaining the operation of the observation signal Figure 6 is a diagram showing one division of the waveform shown in Figure 5 and its spectral distribution; Figure 7 is a diagram to explain the waveform division thereof; Graph 7 shows the relationship between the DC component ratio and center frequency of the divided waveform shown in FIG. A waveform diagram showing only the reflected signal waveform from the detected object by removing unnecessary reflected signals from the reflected signal waveform shown in FIG. 10; FIG. 10 is a cross section showing the detected object corresponding to the reflected signal waveform shown in FIG. 9. Figure; Figure 11 is a configuration diagram required for explanation when detecting multiple cross-sectional information; Figure 12 is a cross-sectional diagram showing the detected object obtained from the processing result of 1 ton of multi-sectional information; Figure 13 is , it will be explained that the reflected wave from the detected object is obtained as a hyperbolic shape. Schematic diagram; Fig. 14 is a principle diagram of synthetic aperture processing; Fig. 15 is a sectional view showing a detected object obtained as a result of synthetic aperture processing; Fig. 16 is an underground object showing an embodiment of the present invention. 16A to 16D are diagrams showing different internal structures of the convenience unit shown in FIG. 16 using block diagrams. 7... Sampling device, 10... Display device, 14
... Antenna device, 15... Computing unit, 15m... Frequency analysis section, 15b... Multi-section correlation processing section, 15a... Synthetic aperture processing section. Applicant's representative Patent attorney Takehiko Suzue Humidity (m) L J's 07 torr intensity voltage (m ¥) Oki TV Shu; ) Reading (m) Electricity/F (mV) Distance, (m) 5〒Night (m) 5 Accumulation (m) Large/4N ToN 11

Claims (4)

[Claims] (1) A step of receiving an observation signal that can capture an electromagnetic wave, which is a reflected signal from an object, as a time change in amplitude; a step of dividing the observation signal into predetermined time intervals; a step of dividing the observation signal into the divided observation signal. converting into a frequency domain and obtaining a spectral distribution; and obtaining a spectral peak frequency f_p from the spectral distribution.
, the DC component ratio R_d_c, and the half-width W; and among the parameter values of the spectral distribution, the spectral peak frequency f_p within a predetermined frequency range; The DC component ratio R_d_c within the component ratio range
or extracting only the observed signal from the detected object by removing signals having respective values other than the half-width W within a predetermined half-width range as unnecessary reflected signals; A step of calculating a hyperbolic shape having a vertex at (X_o, Z_o) on the ground plane to which the observed signal extracted in the step of extracting only the observed signal, and a step of calculating the waveform amplitude on the calculated hyperbola of the hyperbola. a synthetic aperture processing step consisting of a step of adding to the amplitude of the vertex (X_o, Z_o); a step of displaying the synthetic aperture-processed observation signal as a cross-sectional image with improved horizontal resolution of the detected object How to detect objects. (2) Transmitting/receiving means for transmitting electromagnetic waves and receiving reflected waves of the electromagnetic waves from objects as observation signals; sampling means for sampling the observation signals; A/D converting the signals sampled by the sampling means; After that, signal dividing means divides the signal at predetermined time intervals; means converts the divided signal into a frequency domain and calculates a spectral distribution; and calculates a spectral peak frequency f_p and a DC component ratio from the calculated spectral distribution. The parameter values of the spectral distribution such as R_d_c and half width W are read, and among the parameter values, the spectral frequency f_p that is within a predetermined frequency range, the DC component ratio R_d_c that is within a predetermined DC component ratio range, and the predetermined half width are determined. means for extracting only the observation signal from the detected object by removing observation signals having respective values other than the half width W within the value width range as unnecessary reflected waves; The observation signal extracted by the means for extracting corresponds to (X
Synthetic aperture processing means comprising means for calculating a hyperbolic shape having vertices at _o, Z_o), and means for adding the calculated waveform amplitude with the hyperbola to the operation of the vertices (X_o, Z_o) of the hyperbola; An object detection device comprising a display means for displaying an observation signal subjected to synthetic aperture processing as a cross-sectional image of an object to be detected with improved horizontal resolution. (3) receiving multiple observation signals as multi-sectional information that can capture electromagnetic waves, which are reflected signals from objects, as time changes in amplitude; receiving each of the multiple observation signals at predetermined time intervals; dividing each of the plurality of divided observation signals into a frequency domain to obtain a spectral distribution; and obtaining a spectral peak frequency f_p and a DC component from each of the spectral distributions corresponding to each of the plurality of observation signals. reading at least two spectral distribution parameter values out of the ratio R_d_c and the half width W; the spectral peak frequency f_p falling within a predetermined frequency range among the respective spectral distribution parameter values;
, the DC component ratio R_d within a predetermined DC component ratio range.
Only the observation signal from the detected object is extracted by removing the observation signal having a value other than _c or the half-width W within the predetermined half-width range as an unnecessary reflected signal. step; performing a correlation calculation between the multi-sectional information corresponding to the extracted observation signal and extracting only the observation signal from the detected object having a linear structure; A step of calculating a hyperbolic shape with (X_o, Z_o) as the apex on the interrupted plane, and a step of calculating the calculated waveform amplitude on the hyperbola at the apex of the hyperbola (X_o, Z_o).
o) A synthetic aperture processing step consisting of a step of adding to the amplitude of the multi-section information; A method for detecting an object comprising the steps of displaying a cross-sectional image of the object to be detected. (4) a transmitting/receiving means for transmitting electromagnetic waves and receiving a plurality of observation signals as multi-sectional information, which can capture the electromagnetic waves, which are reflected signals from an object, as time changes in amplitude; and sampling the plurality of viewing side signals. a sampling means; a signal dividing means for A/D converting each of the signals sampled by the sampling means and then dividing the signals at predetermined time intervals; converting each of the plurality of divided observation signals into a frequency domain; means for calculating a spectral distribution; reading parameter values of at least two of the spectral peak frequency f_p, DC component ratio R_d_c, and half-width W from each of the spectral distributions corresponding to each of the plurality of observed signals; Among the parameter values, the spectral peak frequency f_p is within a predetermined frequency range, the DC component ratio R_d_c is within a predetermined DC component ratio range, or the half-width W is within a predetermined half-width range. means for extracting only the observation signal from the detected object by removing the observation signal as an unnecessary reflected signal; performing a correlation calculation between the multi-sectional information corresponding to the extracted observation signal to detect the object having a linear structure; means for extracting only the observation signal from the detected object; means for calculating a hyperbolic shape having vertices at each point of the point cross section to which the observation signal from the detected object having the extracted linear structure corresponds; a synthetic aperture processing means comprising means for adding the waveform amplitude on the hyperbola to the amplitude of each vertex of the hyperbola; performing a correlation calculation between the multi-section information and adding the observed signal subjected to the synthetic aperture processing to the horizontal direction; An object detection device comprising means for displaying a cross-sectional image of a linearly structured object to be detected with improved resolution.