JP2003107164A - Aperture synthesys survey device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aperture synthesys survey device having a good resolution by correctly estimating the speed of a propagation wave even when the speed thereof is changed in internally surveying underground or concrete. SOLUTION: The survey device is provided with a transmitter-receiver accommodating a transmitter and receiver of propagation waves, a moving position detecting sensor provided with the transmitter-receiver, and a display device for displaying the results of signal processing using a detected position signal. Based on reflection echo data obtained by transmitting and receiving a propagation wave whenever the transmitter-receiver moves a given distance and a position signal of the transmitter-receiver measured at the same time of transmission-reception, a plurality of images obtained by modifying the speed of the propagation wave as a parameter are compared with each other. Then, the speed of propagation wave is estimated based on the degree of concentration and strength of image data, thereby good survey images can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the locations of cavities inside concrete in buildings, cold joints, corrosion of reinforcing bars and cracks, underground buried objects, cavities and faults, etc.
The present invention relates to an aperture synthetic exploration device that visualizes a shape with elastic waves or electromagnetic waves.

[0002]

2. Description of the Related Art In the conventional internal exploration of concrete using elastic waves, the acoustic velocity of elastic waves varies depending on the quality of concrete when the inside is visualized from the propagation time and propagation velocity data of the waves reflected at the defect boundary surface. , Accurate measurement was difficult.

[0003] In addition, since high-frequency attenuation is large in concrete and underground, it is several tens of KH in the case of concrete exploration.
z, in the case of underground, the elastic wave in the low frequency region of 1 KHz or less must be used, and since the propagation wave is originally high in speed, the wavelength is long and directivity is lacking. With conventional exploration methods that image concrete and underground cross-sections on the assumption that there is an exploration target, it was difficult to grasp the shape of the exploration target due to insufficient resolution.

Further, in the exploration with electromagnetic waves, it is said that there is a feature that the measurement results can be visually displayed with good working efficiency, but since the propagation speed of electromagnetic waves is significantly affected by the water content, the depth measurement accuracy is improved. Is left with a problem.

[0005]

As described above, in the exploration by the reflection method using elastic waves or electromagnetic waves, the velocity fluctuation of the wave propagating in the medium to be explored is large, and hence the reflection obtained by the exploration is performed. Since the velocity of the propagating wave could not be estimated from the wave data, it was difficult to make an accurate survey.

[0006] Further, in the exploration by the reflection method using elastic waves or electromagnetic waves, the transmission beam spreads because the wavelength is relatively long, and the concrete or underground section is imaged on the assumption that the exploration target is in front of the transceiver. It has been difficult to grasp the shapes of buried objects, cavities, and boundary surfaces in concrete and underground by the conventional exploration method.

[0007] The present invention has been made in view of the above situation, and its problem is the velocity of a propagating wave when exploring the ground or the inside of concrete by a reflection method using a propagating wave such as an elastic wave or an electromagnetic wave. The present invention is to provide an aperture synthetic surveying device that can accurately estimate the velocity even when fluctuates depending on the situation and has good resolution.

[0008]

In order to solve the above-mentioned problems, the invention according to claim 1 is a movable transmitter / receiver housing a transmitter and receiver of a propagating wave, and a position installed in the transmitter / receiver. In an aperture synthesis exploration device including a detection sensor and a display device that displays a result of signal processing using the detected position signal, the synthetic aperture device is obtained by transmitting and receiving a propagating wave each time the transceiver device moves by a predetermined amount. Reflected echo data and position signals of the transmitter / receiver measured at the same time as transmission / reception are compared to compare a plurality of images obtained by changing the propagation velocity of a propagating wave as a parameter, and based on the degree of concentration and intensity of the image data. It is characterized by estimating the velocity of a propagating wave.

According to a second aspect of the present invention, in the aperture synthetic exploration apparatus according to the first aspect, a B-scope imaging result is obtained by imaging the cross section of the medium from the reflection echo data in a state where the transmission / reception sensitivity of the transceiver is maximized. Therefore, the position of the reflection point having a large reflection directivity angle is determined by the locus curve in the image, and the search target position is estimated from the apex position of this locus curve.

According to a third aspect of the present invention, in the aperture synthetic exploration apparatus according to the second aspect, the reflection echo used for displaying the locus curve is defined as an imaging region near a reflection point position having a large reflection directivity angle. By directly observing a plurality of images obtained by performing aperture synthesis processing using the velocity of the propagating wave as a parameter using the data, the propagating wave velocity at which the image is most concentrated is determined, and the entire exploration is performed using the velocity data. It is characterized by synthesizing images.

According to the first to third aspects of the present invention, an image of a limited area in the vicinity of an edge portion of an object to be inspected or an object to be inspected is continuously displayed by using a velocity of a propagating wave as a parameter, and a true judgment is made based on the result. By combining and displaying the entire image using the speed data of 1, the clear image with good resolution can be displayed on the display device.

According to a fourth aspect of the present invention, in the aperture synthetic exploration apparatus according to any one of the first to third aspects,
Propagation waves are transmitted from the transmitter to the inside of the ground where a homogeneous medium is formed with clear boundaries, and propagated based on the boundary shape data obtained by visualization of the homogeneous medium near the transceiver. The wave refraction calculation is performed, and the imaging results are compared using the propagation wave velocity in the region far from the transceiver that is in contact with the boundary as a parameter, the propagation wave velocity at which the image is most concentrated is determined, and the velocity data is used. It is characterized by synthesizing the whole search image. According to the fourth aspect, the true speed can be obtained by comparing the concentration of the image data.

According to a fifth aspect of the present invention, in the aperture synthetic survey apparatus according to the first aspect, a plurality of transmitters and a plurality of receivers are arranged at predetermined positions, and transmission / reception of propagating waves is switched by a switching circuit. , It collects the received echo data for visualization, and increases the exploration depth by using the received echo data obtained from a plurality of transmitters and receivers. According to claim 5, it is possible to more accurately grasp the shape and position of the exploration target in a relatively homogeneous medium such as underground or concrete.

According to a sixth aspect of the present invention, in the aperture synthetic exploration apparatus according to the fifth aspect, an electromagnetic wave is used as a transmitted wave,
Increase the search depth by arranging multiple transceivers that can perform transmission and reception with the same antenna, and by using the received echo data obtained from multiple transceivers by the switching circuit that can arbitrarily switch the transceivers. It is characterized by According to the sixth aspect, it is possible to improve the exploration image by arbitrarily switching the transmitter / receiver and transmitting / receiving.

Visualization by the aperture synthesis method used in the present invention is performed by moving a wide directional transceiver or by using a large number of transceivers arranged in a plane to detect elastic waves and electromagnetic waves transmitted and received at various positions. This is a method of statistically obtaining the position of reflection from the reflected echo data and the velocity value of the propagating wave in the medium. For that purpose, the reflected echo waveform data is layered in layers of equal propagation time (or curved surface) according to the position of the transceiver in the propagation distance direction, and waveform amplitude data corresponding to the propagation time is applied on the same curve (curved surface). And deploy it in the imaging space,
A fine image can be displayed by subjecting these values to addition processing for all combinations of transmitters and receivers in the imaging space. However, if the velocity of the propagating wave is not accurate, the original position of the object to be searched cannot be focused.

The present invention is a method for estimating the velocity of a propagating wave by reversely utilizing the above phenomenon. In particular, point reflection sources such as minute inclusions contained in the medium and reflection echoes from sharp edges have a wide reflection directivity. By imaging a concrete or underground section on the assumption that there is an object, the position can be confirmed by the large convex curve called the locus curve appearing.

Since the apex of this locus curve coincides with the position of the point reflection source or the sharp edge portion, the velocity of the propagating wave is directly changed in a small region (for shortening the calculation time) near this position. It is possible to specify the velocity of the propagating wave by performing image formation by aperture synthesis (in particular, stereoscopic image formation), and displaying and observing an image of a point reflection source or a sharp edge portion with the propagation velocity as a parameter.

From the above, the conventional search method cannot perform a fine search because the directivity of the transmitted wave is wide.
The synthetic aperture exploration method is characterized in that the transmitted / received waves having a wide directivity angle are statistically added by securing a wide aperture to improve the S / N and obtain a high-resolution image. Since three-dimensional imaging can be performed by arranging the transmitters and receivers in a plane, it becomes possible to grasp the shape of buried objects, cavities, boundaries, etc. in concrete and underground.

Further, in order to visualize the inside of the earth, which has a relatively clear boundary such as a fault, with an elastic wave or an electromagnetic wave, the boundary line (or the boundary line obtained by the visualization of the homogeneous medium portion near the transmitter / receiver) Curve (or curved surface) of equal propagation time obtained by calculating refraction of elastic wave or electromagnetic wave based on the shape of (boundary surface) and velocity data of the propagating wave before the boundary
Are layered in the propagation distance direction, and the waveform amplitude data corresponding to the propagation time is mapped on the same curve (curved surface) and developed in the imaging space. By comparing and observing images that seem to be point reflection sources and sharp edge portions, it is possible to obtain a good exploration image in an area through a boundary surface such as a tomographic section.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an aperture synthetic exploration device according to a first embodiment (corresponding to claims 1 to 3) of the present invention.

As shown in FIG. 1, a transmitter 11 and a receiver 12 for transmitting and receiving propagating waves such as elastic waves and electromagnetic waves are housed in a mobile transmitting / receiving device 13. The transmitter / receiver 13 includes a moving position detection sensor 1 for continuously measuring the moving position.
4 is installed and outputs the detected movement position signal to the measuring device 15.

On the other hand, the measuring device 15 outputs a transmission command to the transmitter 11 and transmits a transmission beam E of a propagating wave each time the moving position of the transmitting / receiving device 13 changes by a predetermined amount, so that the medium 1 in the relatively homogeneous medium 1 is transmitted. The reflected wave reflected by the search target 2 is received by the receiver 12, amplified, and then output to the measuring device 15.

The broken line in the figure shows transmission / reception when the transmitter / receiver 13 is moved. Since the transmission beam E has a wide directional angle, it is broken from the position of the transmitter / receiver 13 shown by the solid line. While moving to the position of the transmission / reception device 13 shown by, the receiver 12 can always receive the reflected wave from the search target 2. In the figure, P1 indicates the propagation path of the transmission / reception wave before movement, and PN indicates the propagation path of the Nth transmission / reception wave at the position of the transmission / reception device 13 after movement indicated by the broken line.

In the measuring device 15, the reflection echo data collected while moving the transmitting / receiving device 13 and the transmitting / receiving device 13
The process of synthesizing the search image is performed based on the moving position data.

FIG. 2 is an image of a dot-shaped search target 2 which is smaller than the wavelength of a propagating wave in a relatively homogeneous medium 1 on the assumption that the search target 2 is located in front of the moving position of the transmitter / receiver 13. Here is an example. In the figure, since the transmission beam E has a wide directivity angle, the display image is displayed as an image having a convex shape called a locus curve 20. Since the apex of the locus curve 20 coincides with the actual position of the search target 2 (moving direction of the transmitting / receiving device), position identification in the moving direction (horizontal direction) of the transmitting / receiving device can be performed.

By the way, in the imaging by aperture synthesis according to the present invention, the reflected echo data is transmitted by the transmitter 11 and the receiver 12.
An ellipsoid (or spheroid), which is a curve representing the equal propagation time from the position of, is layered in the propagation distance direction in multiple layers, and the waveform amplitude data corresponding to the propagation time is mapped on the same curve (curved surface) and imaged. A fine image can be displayed by expanding in space and adding those values for all combinations of the transmitter and the receiver.

Next, FIG. 3 to FIG. 5 show a case in which a search image is synthesized by aperture synthesis using the same reflected echo data and the moving position data of the transmitting / receiving device 13. 3 to 5
Is the transmitter 11 in order to accurately obtain the propagation velocity of the propagating wave.
Output power and the sensitivity of the receiver 12 are maximized, and minute inclusions in the relatively homogeneous medium 1 or the edge portion 2 of the inspection object
5 while moving the transmitter / receiver 13 in a state that can detect
Peak position (time) of reflected waveform after transmission and reception (N = 5)
Ellipse corresponding to (21-25, 31-35, 41-4
5) is drawn. That is, 21 to 25 in FIG.
Is a spheroid when the propagation velocity is low, 31 to 35 in FIG. 4 are spheroids when the propagation velocity is correct, and 41 to 45 in FIG.
Is a spheroid when the propagation velocity is high, D is the depth direction passing through the apex of the locus curve, and f is the image data intensity.

FIG. 3 shows an image in which the velocity of the propagating wave is slower than the true value. Since the diameter of the ellipse is short, the whole image is scattered and the image is displayed above the search target position. Figure 4 shows the case where the velocity of the propagating wave matches the true value,
The ellipses intersect at one point and coincide with the position of the search target 2. FIG. 5 shows a case in which the speed is made faster than the true value. Contrary to FIG. 3, the ellipse has a long diameter, so that the whole is scattered and an image is displayed below the search target position.

Based on the above principle, images of a limited area near the edge of the inclusion or the object to be inspected are continuously displayed with the velocity of the propagating wave as a parameter, and the true velocity data judged based on the result is displayed. By combining and displaying the whole image by using it, a clear image with good resolution can be displayed on the display device 16.

FIG. 6 shows a second embodiment of the present invention (claim 4).
It is a block diagram of the aperture synthetic exploration device of (correspondence), and the comparatively clear boundary part 7 such as a stratum, which is on the opposite side of the exploration side in contact with the boundary part 7 via the medium 5 on the exploration side of the boundary part 7. The conceptual diagram which searches the object 2 to be searched in the medium 6 by the aperture synthesis method is shown.

According to the present embodiment, the shape of the boundary portion 7 visualized by the method of continuously displaying the image of the limited area with the velocity of the propagating wave as a parameter and the medium 5 on the exploration side of the boundary surface. Curves (or curved surfaces) 51 of equal propagation times in the medium 6 on the side opposite to the exploration side in contact with the boundary portion 7 obtained by performing refraction calculation of the propagation wave based on the velocity data of the true propagation wave Since 55 changes as shown in FIGS. 3 to 5 by changing the velocity of the propagating wave, it is possible to obtain the true velocity by comparing the concentration of image data.

FIG. 7 is a block diagram of an aperture synthetic exploration apparatus according to the third embodiment (corresponding to claim 5) of the present invention. A transmitter 11 and a receiver 1 for transmitting and receiving propagating waves such as elastic waves or electromagnetic waves.
It shows a conceptual diagram in which a plurality of 2's are arranged on a plane and transmitted / received to three-dimensionally explore the ground or concrete.

According to this embodiment, a plurality of transmitters 11
Is capable of switching the transmission of the transmission beam E at high speed by fetching a transmission command from the measuring device via the signal switching unit 17. It is assumed that the measuring device 15 captures all the reflected echo data received by all the receivers 12 via the signal switching device 17 between transmission switching. The synthesis of the search image is the same as in the second embodiment of FIG. 6, but by displaying all the images in three dimensions, the shape and position of the search target in a relatively homogeneous medium such as underground or concrete can be determined. It becomes possible to grasp more accurately.

FIG. 8 is a block diagram of an aperture synthetic exploration apparatus according to a fourth embodiment of the present invention (corresponding to claim 6). The present embodiment is different from the third embodiment in FIG. 7 in that a transmitter / receiver 18 is used as the transmitter 11 and the receiver 12, and other configurations are the same, and therefore, the same portions are denoted by the same reference numerals. The duplicate description is omitted.

According to the present embodiment, when electromagnetic waves are used, the functions of the transmitter 11 and the receiver 12 can be realized by the same antenna. Therefore, the transmitter / receiver integrated transmitter / receiver 18 for both transmission and reception is provided in the transmitter / receiver 13. By accommodating a plurality of them and arranging them on a plane, the search image can be improved by transmitting / receiving the transmitter / receiver 18 in an arbitrary combination.

[0036]

As described above, according to the present invention,
Even when the velocity of the propagating wave varies depending on the situation when exploring the inside of the ground or concrete by the reflection method using propagating waves such as elastic waves and electromagnetic waves, the velocity can be accurately estimated and the aperture has a good resolution. It becomes possible to provide a synthetic exploration device.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an aperture synthetic exploration device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing imaging of a locus curve.

FIG. 3 is an exploration image diagram by aperture synthesis when the velocity of a propagating wave is low.

FIG. 4 is an exploration image diagram based on aperture synthesis when the velocity of a propagating wave is a true value.

FIG. 5 is an exploration image diagram by aperture synthesis when the velocity of a propagating wave is high.

FIG. 6 is a configuration diagram of an aperture synthetic exploration device according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram of an aperture synthetic exploration device according to a third embodiment of the present invention.

FIG. 8 is a configuration diagram of an aperture synthetic exploration device according to a fourth embodiment of the present invention.

[Explanation of symbols]

1 ... Relatively homogeneous medium, 2 ... Object to be probed, 5 ... Medium before boundary, 6 ... Medium beyond boundary, 7 ... Boundary,
11 ... Transmitter, 12 ... Receiver, 13 ... Transceiver, 14
... moving position detection sensor, 15 ... measuring device, 16 ... display device, 17 ... signal switcher, E ... transmission beam, P1 ... propagation route 1, PN ... propagation route N, 21, 22, 23, 24, 2
5 ... Low spheroid 1, same spheroid 2, same spheroid 3, same spheroid 4, same spheroid 5, D ... depth direction passing through apex of locus curve, f ... Image data intensity, 31, 32, 33, 34, 35 ... Spheroid 1, same spheroid 2, same spheroid 3, same spheroid 4, same spheroid 5, 41 when propagation velocity is correct , 42, 4
3, 44, 45 ... Spheroid 1, same spheroid 2, same spheroid 3, same spheroid 4, same spheroid 5, 51, 52, 53, 54, 55 when propagation velocity is high Equal propagation time curved surface 1, same curved surface 2, same curved surface 3, same curved surface 4, same curved surface 5.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G01S 15/88 G01S 15/88 G01V 3/12 G01V 3/12 BF term (reference) 2G047 AA07 AA10 BA03 BC09 BC11 BC18 CB01 EA10 GF20 GG21 GG34 GG35 GH06 5J070 AB01 AC01 AE11 AF02 AK22 BE02 5J083 AA02 AB12 AC28 AD01 AD13 BA01 DC02

Claims (6)

[Claims] 1. A movable transmitter / receiver housing a propagating wave transmitter and receiver, a position detection sensor installed in the transmitter / receiver, and a result of signal processing using the detected position signal. In the aperture synthetic exploration device with a display device, reflected echo data obtained by transmitting and receiving a propagating wave each time the transceiver device moves a predetermined amount, from the position signal of the transceiver device measured at the same time as transmission and reception, An aperture synthetic exploration apparatus characterized in that a plurality of images obtained by changing the propagation velocity of a propagating wave as a parameter are compared, and the velocity of the propagating wave is estimated based on the concentration degree and intensity of image data. 2. The aperture synthetic exploration apparatus according to claim 1, wherein a cross section of the medium is imaged from the reflection echo data with the transmission / reception sensitivity of the transmitter / receiver maximized, and the reflection directivity angle An aperture synthetic exploration device characterized in that the position of a large reflection point is determined by a locus curve in an image, and the exploration target position is estimated from the vertex position of this locus curve. 3. The synthetic aperture exploration apparatus according to claim 2, wherein the vicinity of a reflection point position having a large reflection directivity angle is set as an imaging region, and the reflected wave data used for displaying the locus curve is used to propagate a propagation wave. By directly observing a plurality of images obtained by performing aperture synthesis processing using the velocity of as a parameter, the propagation wave velocity at which the image is most concentrated is determined, and the entire search image is synthesized using the velocity data. Characteristic synthetic aperture exploration device. 4. The synthetic aperture exploration apparatus according to claim 1, wherein the transmitter transmits a propagating wave into the ground where a homogeneous medium forms a clear boundary. Then, based on the shape data of the boundary portion obtained by visualization of the homogeneous medium portion near the transceiver, refraction calculation of the propagating wave is performed, and the image with the velocity of the propagating wave in the region far from the transceiver contacting the boundary portion as a parameter Compare the results of
An aperture synthetic exploration apparatus, characterized in that a propagating wave velocity at which an image is most concentrated is determined and the entire exploration image is synthesized using the velocity data. 5. The aperture synthetic exploration apparatus according to claim 1, wherein a plurality of transmitters and a plurality of receivers are arranged at predetermined positions, and transmission / reception of propagating waves is switched by a switching circuit, thereby receiving for visualization. An aperture synthetic exploration apparatus, which increases echo exploration depth by collecting echo data and using received echo data obtained from a plurality of transmitters and receivers. 6. The switching synthetic circuit according to claim 5, wherein a plurality of transceivers that use electromagnetic waves as transmission waves and can perform transmission and reception with the same antenna are arranged, and the transceivers can be arbitrarily switched. By using the received echo data obtained from a plurality of transmitters / receivers, the aperture synthetic exploration apparatus is characterized by increasing the exploration depth.