JPH1114743A - Buried object investigating method and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove surface reflection wave, when the existence and the position of a buried object is investigated from the reflected image by moving electromagnetic waves while transmitting and receiving them against the surface of concrete or the like. SOLUTION: The receiving directivity of electromagnetic waves is made unsymmetric in front and rear of the moving direction of a moving body, and the moving body is moved from one end to the other end of a place to be investigated so as to obtain a first reflected image (A). In addition to this, it is moved again from the other end to the one end, so as to obtain a second reflected image (B) conforming the investigating position to the first reflected image (A), and the existence and the position of a buried object is investigated by the difference image (C) of the first reflected image (A) and the second reflected image (B).

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 detecting a buried object for detecting a buried object in a concrete building or the ground using electromagnetic waves.

[0002]

2. Description of the Related Art For example, when a buried object buried in a concrete building is transmitted / received an electromagnetic wave from the concrete surface to search for the buried object by a reflected wave, especially when the buried position of the buried object is shallow, There is no temporal difference between the reflected wave from the concrete and the reflected wave from the concrete surface. For example, the reflected image overlaps on a B-scope display, etc., and the presence of the buried object is detected because the reflected wave from the concrete surface is stronger. become unable. Therefore, in order to search for a buried object with this kind of buried object detection device, a means for removing a surface reflected wave is required.

One of the prior arts for removing surface reflected waves is as follows.
There is a prior art disclosed by the present applicant in Japanese Patent Publication No. Hei 7-117584 “buried object search device”. As shown in FIG. 7, this prior art has a circuit that receives a reflected wave of a radio wave transmitted from an antenna section toward a structure or the ground and receives the reflected wave from the antenna section and displays the reflected waveform. In a buried object exploration device that displays the presence and position of a buried object inside the structure or the ground, the antenna unit includes a pair of transmitting antennas and receiving antennas arranged adjacent to each other,
A storage circuit for storing a reflected wave signal of only the structure or the ground surface received by the antenna, and calculating a difference between a previous reflected wave signal input from the storage circuit and a current reflected wave signal from the antenna after moving; It consists of a subtraction circuit for calculating and a circuit for displaying the waveform of the difference signal, and stores the reflection waveform at a place where there is no buried object. To conduct exploration.

[0004]

In the prior art as described above, it is necessary to find a place where no buried object exists in the same concrete building or the like prior to exploration of the buried object and store its reflection waveform. In this case, if a place where a buried object is buried is stored by mistake, a search for a place where there is no buried object is displayed as if the buried object is present. Further, a plurality of buried objects (for example, the buried object 40 and the buried object 4 as shown in FIG.
In the case where 2) exists, there is a problem that a very slight difference appears in the reflected waveform, and the existence of the buried object 42 in a deep place may be overlooked.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is not necessary to store a reflected image of a place where no buried object exists, and a reflected image from which surface reflected waves have been removed can be obtained. It is an object of the present invention to provide a method and an apparatus for exploring a buried object capable of detecting a buried object even when another buried object exists under one buried object.

[0006]

According to the method for searching for a buried object according to the present invention, a moving object for transmitting and receiving an electromagnetic wave is moved at a location to be detected on a structure or the ground to obtain a reflection image of the entire location to be detected. In the underground object exploration method for exploring the existence and position of an object to be buried in an area to be searched, the reception directivity of the electromagnetic wave is asymmetrical before and after the moving direction of the moving body, and is moved from one end to the other end of the area to be searched. To obtain a first reflection image, move the second reflection image from the other end to one end again, and obtain a second reflection image in which the search position is matched with the first reflection image. The present invention is characterized in that the presence and the position of a buried object are searched for based on an image of a difference from the second reflected image.

Further, when the receiving directivity is moved from one end to the other end of the area to be searched while moving the receiving directivity of the electromagnetic wave back and forth in the moving direction of the moving body, the receiving directivity is changed in the forward direction of the moving direction. The presence and the position of the buried object are determined by the difference image between the first reflection image acquired by the reflected wave and the second reflection image acquired by the reflection wave when the receiving directivity is swung in the backward direction of the moving direction. It is characterized by exploration.

Further, in the apparatus for searching for a buried object according to the present invention, a transmitting antenna, a receiving antenna, and a moving distance detecting means are arranged on a moving body, and the moving object is moved while moving an object to be detected on a structure or the ground. A reflected wave of the electromagnetic wave transmitted from the transmitting antenna toward the structure or the ground is received by the receiving antenna, and a reflection image of the entire area to be detected is obtained based on the position information from the moving distance detecting means. In a buried object detection device for detecting the presence and position of a buried object in a structure or the ground in a reflected image, a means for making the directivity of the receiving antenna asymmetrical in a moving direction of the moving object before and after the moving object, Is moved from one end to the other end of the area to be searched, and the second reflected image is moved again from the other end to one end, and the second reflected image is obtained by aligning the first reflected image with its search position. A storage means for storing the reflection image, characterized by comprising a display means for displaying an image of a difference between said first reflecting image and the second reflecting image.

Means for causing the directivity of the receiving antenna to move back and forth in the direction of movement of the moving body; and moving the moving body from one end to the other end of the area to be searched to change the directivity of the receiving antenna to the moving direction. A first reflection image acquired by a reflected wave received when the antenna is swung in the forward direction, and a second reflection image acquired by a reflected wave received when the directivity of the receiving antenna is swung in the backward direction in the moving direction. And a display means for displaying an image of a difference between the first reflection image and the second reflection image.

The means for making the directivity of the receiving antenna asymmetrical before and after the moving direction may be a means for inclining the arrangement angle of the receiving antenna or a means for making the antenna electrically asymmetric by using a phased array antenna. It is characterized by being used.

Further, the means for causing the directivity of the receiving antenna to swing back and forth in the moving direction is a means for electrically swinging the antenna using a phased array antenna.

With the above-described configuration of the method and apparatus for measuring an object to be buried according to the present invention, an image of the same surface reflected wave is recorded in the first reflected image and the second reflected image. The reflected waves from the buried object are recorded as images from different angles. Therefore, in the image of the difference between the first reflected image and the second reflected image, the surface reflected wave is removed, and the reflected wave from the buried object is displayed from two angles, and the buried object is buried. The surface reflected wave can be removed without having to store the reflected image of the non-existent portion, and the embedded object existing under the embedded object can be detected.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the device configuration of the embedded object exploration device of the present invention. In FIG. 1, 1 is an antenna unit, 2 is a main unit display unit, 3 is an antenna cable connecting the antenna unit 1 and the main unit display unit 2,
Reference numeral 4 denotes a concrete structure to be symmetrically searched. Further, in the antenna unit 1, 11 is a transmitting circuit, 12 is a transmitting antenna, 13 is a receiving circuit, 14 is a receiving antenna,
5 is a distance detection circuit, and 16 is a moving wheel. Further, in the main body display unit 2, reference numeral 21 denotes an input circuit, 22 denotes an image processing unit, 23 denotes a display circuit, and 24 denotes a storage circuit.

In the antenna section 1, an electric signal (for example, a pulse signal) generated in the transmission circuit 11 is transmitted by the transmission antenna 12 to the concrete building 4 by electromagnetic waves. The transmitted electromagnetic wave is first reflected on the surface of the concrete building 4 and received by the receiving antenna 14. Electromagnetic waves that are not reflected on the surface of the concrete building 4 and enter the inside thereof are reflected on, for example, the buried objects 40 and 41, and the reflected waves are received by the receiving antenna 14. Receiving antenna 1
The reflected wave received at 4 is converted into an electric signal by the receiving circuit 13 and input to the main body display unit 2 via the antenna cable 3 as a received signal. The antenna 1 has wheels 1
A distance detection circuit for detecting a movement distance from the rotation of the motor 6 is provided, and a distance signal is transmitted to the input circuit 21 via the antenna cable 3 every time the antenna unit 1 moves a predetermined distance. . The configuration of the antenna unit 1 according to the present embodiment is the same as that shown in FIG. 7 is similar to the prior art antenna unit 1a.

In the main body display section 2, a reception signal and a distance signal transmitted from the antenna section 1 are input to an input circuit 21. Each time the input circuit 21 receives the distance signal from the antenna unit 1, the input circuit 21
D-converted and transmitted to the image processing unit 22. Image processing unit 22
Then, the received signal converted into a digital signal is converted into a color, the display address is specified on the display 23, and a display process described later is performed, and an image signal is transmitted to the display 23. It is configured to display a B scope as shown in FIG.

Next, the search operation of the present invention will be described.
As shown in FIGS. 1 and 2, in the device of the present embodiment, the reception directivity of the receiving antenna 14 changes from the vertical direction to the forward direction (the traveling direction indicated by the symbol A) or the backward direction (not shown) of the antenna unit 1. It is inclined by a predetermined angle and is asymmetrical in the front and rear directions of movement. Then, as shown in FIG. 3, for example, when a search between M and N is performed, a B scope image of the entire area to be searched is obtained while moving from M to N once, stored in the storage circuit 24, and further stored in the storage circuit 24. While moving to M again, a B scope image of the entire area to be searched is acquired and stored in the storage circuit 24.

FIG. 4A is a B-scope image acquired while moving from M to N, and FIG. 4B is a B-scope image acquired while moving from N to M. Surface reflected wave, 400 is buried object 4
A reflected wave from 0, 410 indicates a reflected wave from the buried object 41. In FIG. 4, the reflection image obtained by searching while moving from M to N is recorded from the M side as shown by the arrow in FIG. 4A, and is obtained by searching while moving from N to M. The reflection image is stored from the N side as indicated by an arrow in FIG. 4B, and a display operation for matching the search positions of the two reflection images is performed. This display operation is performed by, for example, converting the display address in the image processing unit 22.

The reason why each reflected wave is displayed in a multi-layer state is that ringing occurs due to antenna characteristics, and the reflected signal 4 from each buried object.
00 and 410 are asymmetric when the receiving antenna 14 is far, and shallow when the receiving antenna 14 is near, and since the directivity of the receiving antenna 14 is inclined, the one hem portion is long and the other hem portion is short. Becomes The present invention extracts only the reflection image of the buried object by utilizing the asymmetry of the reflection image of the buried object.

That is, the B scope image stored in the storage circuit 24 while moving from M to N once (ie, FIG.
By taking the difference between the image shown in FIG. 4A and the B scope image stored in the storage circuit 24 while moving from N to M again (that is, the image shown in FIG. 4B),
As shown in (C), the surface reflected wave 100 is removed and 2
Reflection image 40 from each buried object that was asymmetric in one image
Only 0 and 410 remain, which are displayed on the display 23. Therefore, as in the prior art, it is not necessary to store a reflection image of a place where there is no buried object, and when there is a buried object, a reflection image of only the buried object is displayed. An image without any reflection image is displayed, so that the presence or absence of an embedded object can be determined very easily.

As shown in FIG. 5, when another buried object 42 exists under the buried object 40, a reflection image only moved once from M to N (this reflection image is shown in FIG. )
), The reflection image 420 of the buried object 42 is
0, and the presence of the buried object 42 cannot be detected. In particular, when the phase of the reflection is reversed, the reflection of the buried object 42 disappears. However, in the present invention, the reflection image is obtained by moving from N to M again as described above (see FIG. A reflection image is shown in FIG. 6B. An image of the difference between the two reflection images (this image is shown in FIG.
By displaying (C), the reflection image 400 of the embedded object 40 and the reflection image 420 of the embedded object 42 can be clearly distinguished and displayed.

In the above embodiment, the receiving antenna 1
Although the installation angle of 4 is inclined to make the reception directivity asymmetrical before and after the moving direction, it may be electrically asymmetrical using a phased array antenna or the like for the antenna. Further, when an antenna such as a phased array antenna capable of oscillating the reception directivity is used, the antenna unit 1 is moved while oscillating the reception directivity back and forth, and the reflection when the antenna is swung forward at each position is determined. If an image of the difference between the reflected image of the entire area to be detected obtained from the signal and the reflected image of the entire area to be detected obtained from the reflected signal when the signal is swung in the backward direction is to be output, the movement of the antenna unit 1 can be improved. Once.

[0022]

As described above, according to the method and the apparatus for detecting a buried object according to the present invention, it is not necessary to store the reflected waveform at a place where no buried object exists, and a reflected image from which the surface reflected wave is removed can be obtained. This makes it easier to search for buried objects buried in shallow places. Further, even when another buried object exists under one buried object, there is an effect that the presence of the buried object below can be detected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the device configuration of the present invention.

FIG. 2 is a diagram illustrating the directivity of a receiving antenna according to the present invention.

FIG. 3 is a diagram illustrating an example of a search operation according to the present invention.

FIG. 4 is a diagram for explaining a reflected image acquired by the search operation described in FIG. 3;

FIG. 5 is a diagram for explaining another example of the search operation of the present invention.

FIG. 6 is a diagram for explaining a reflected image acquired by the search operation described in FIG. 5;

FIG. 7 is a diagram showing a configuration of a buried object search device disclosed in the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna part 2 Main body display part 3 Antenna cable 4 Concrete structure which becomes symmetrical to be searched 11 Transmission circuit 12 Transmission antenna 13 Receiving circuit 14 Receiving antenna 15 Distance detection circuit 16 Wheel for movement 21 Input circuit 22 Image processing part 23 Display circuit 24 Storage circuit 40, 41, 42 Buried object 100 Surface reflected wave 400, 410, 420 Reflected wave from buried object

Claims (6)

[Claims] 1. A moving object that transmits and receives electromagnetic waves is moved at a location to be detected on a structure or the ground to obtain a reflection image of the entire location to be detected, and the presence and position of a buried object buried in the location to be detected are determined. In the method for searching for a buried object to be searched, the reception directivity of the electromagnetic wave is asymmetrical in the front and rear directions of movement of the moving body, and is moved from one end to the other end of the searched area to obtain a first reflection image, and from the other end. Moving to one end again and obtaining a second reflection image in which the first reflection image and its search position are matched, the presence of the buried object based on the difference image between the first reflection image and the second reflection image A method for exploring a buried object, characterized by exploring the position and location. 2. A moving object that transmits and receives electromagnetic waves is moved at a location to be searched on a structure or the ground to acquire a reflection image of the entire location to be searched, and the existence and position of a buried object buried in the location to be searched are determined. In the method for searching for a buried object to be searched, the receiving directivity is moved from one end to the other end of the area to be searched while oscillating the receiving directivity of the electromagnetic wave back and forth in the moving direction of the moving body, and the receiving directivity is shifted in the forward direction of the moving direction. The presence of the buried object by the difference image between the first reflection image acquired by the reflected wave at the time of the reflection wave and the second reflection image acquired by the reflection wave at the time when the receiving directivity is swung in the backward direction of the moving direction. Buried object exploration method to explore the location. 3. A moving body is provided with a transmitting antenna, a receiving antenna, and a moving distance detecting means, and the structure or the ground to be searched is moved from the transmitting antenna to the structure or the ground while moving the moving body. The reflected wave of the transmitted electromagnetic wave is received by the receiving antenna, and a reflection image of the entire area to be searched is acquired based on the position information from the moving distance detecting means. A buried object exploration apparatus for exploring the presence and position of an buried object, wherein: means for making the directivity of the receiving antenna asymmetrical before and after the moving direction of the moving body; A first reflection image acquired by moving to the end, and a second reflection image acquired by moving again from the other end to one end and matching the first reflection image with its search position are stored. Storage means , Buried object exploration device characterized by comprising a display means for displaying an image of a difference between the first reflecting image and the second reflecting image. 4. A moving body is provided with a transmitting antenna, a receiving antenna, and a moving distance detecting means, and the structure or the ground to be searched is directed from the transmitting antenna to the structure or the ground while moving the moving body. The reflected wave of the transmitted electromagnetic wave is received by the receiving antenna, and a reflection image of the entire area to be searched is acquired based on the position information from the moving distance detecting means. A buried object exploration device for exploring the presence and position of an buried object, wherein: means for oscillating the directivity of the receiving antenna back and forth in the moving direction of the moving body; and moving the moving body from one end to the other end of the area to be searched. And the first reflection image acquired by the reflected wave received when the directivity of the receiving antenna is swung in the forward direction of the moving direction, and the directivity of the receiving antenna is swung in the backward direction of the moving direction. Storage means for storing a second reflection image obtained from the reflection wave received when the first reflection image is received, and display means for displaying an image of a difference between the first reflection image and the second reflection image. A buried object exploration device, characterized in that: 5. The means for making the directivity of the receiving antenna asymmetrical in the front and rear directions of the moving direction, the means for inclining the arrangement angle of the receiving antenna, or the means for making it electrically asymmetrical by using a phased array antenna for the antenna The buried object exploration device according to claim 1, wherein the device is used. 6. The device according to claim 2, wherein said means for causing the directivity of said receiving antenna to swing back and forth in said moving direction is a means for electrically swinging said antenna using a phased array antenna. Item 5. A device for exploring a buried object according to any one of items 4.