JP7310380B2 - Buried object detection device and buried object detection method - Google Patents

Description

The present invention relates to an embedded object detection device and an embedded object detection method.

For example, as a device for detecting the position specific data of a position specific object under the detection surface such as a gas pipe or pipe buried in a wall or in the ground, an electromagnetic wave is emitted toward the detection surface and the reflected wave is received. A locating system (a buried object detection device) for detecting a locating object by means of a hand-held locator, in particular, is used (see, for example, Patent Document 1).

Japanese Patent Publication No. 2017-532528

However, the above conventional position specifying system (buried object detection device) has the following problems.
That is, in the above-described conventional device, for example, when detecting wood (buried object) placed behind a gypsum board (object), the difference in dielectric constant between the gypsum board and wood is small. It is difficult to accurately detect a buried object in a method of detecting a buried object in an object by detecting a reflected wave of an electromagnetic wave at an interface where the height changes.

SUMMARY OF THE INVENTION An object of the present invention is to provide an embedded object detection apparatus and an embedded object detection method capable of detecting an embedded object with high accuracy even when the difference in dielectric constant between the object and the embedded object is small.

A buried object detection device according to a first aspect of the present invention is a buried object detection device for detecting a buried object in an object using data on a reflected wave of an electromagnetic wave radiated toward the object, comprising: a main body; section, a receiving section, a variable delay section, and a control section. The radiating section is provided on the main body and radiates electromagnetic waves. The receiver is provided in the main body and receives reflected waves of electromagnetic waves. The variable delay section sets the delay time of the sampling pulse for sampling the reflected wave in the receiving section. The control unit detects an embedded object in the object based on the result of differentiating the reception waveform created by integrating one line of sampling data of the reflected wave received by the reception unit.

Here, in an embedded object detection apparatus for detecting an embedded object in an object using data on reflected waves of electromagnetic waves radiated toward the object, one line of sampling data of the reflected waves received by the receiving unit is obtained. Based on the result of differentiating the reception waveform created by integration, an embedded object in the object is detected.
Here, the buried object detected by this buried object detection device is, for example, wood placed inside the gypsum board as the object. It is possible to consider materials that

As a result, by using the result of differential processing of the received waveform, it is possible to detect the difference in an object with a small difference in dielectric constant, such as wood in a gypsum board, which cannot be detected from the data obtained by integrating the sampling data for one line. can be accurately detected by removing the offset component.

A buried object detection apparatus according to a second aspect of the present invention is the buried object detection apparatus according to the first aspect of the invention, wherein the controller determines that the maximum or minimum peak of the graph obtained as a result of differentiation processing of the received waveform is a predetermined value. If the threshold is exceeded, it is determined that the end of the buried object has been detected.
As a result, depending on whether the maximum or minimum peak of the graph obtained by differentiating the received waveform exceeds a predetermined threshold value, for example, the edge of the buried object existing inside the object and the air Boundaries can be detected.
It should be noted that the threshold used for detecting the edge of the buried object may be changed according to, for example, the combination of the object and the buried object, the material, the thickness, and the like.

A buried object detection device according to a third invention is the buried object detection device according to the second invention, wherein the control unit determines that the buried object exists between the maximum peak and the minimum peak of the graph. do.
By detecting the maximum peak and the minimum peak of the graph obtained by differentiating the received waveform, it is possible to accurately detect the position of the buried object in the scanning direction of the buried object detection device. be able to.

A buried object detection device according to a fourth aspect of the invention is the buried object detection device according to the third aspect of the invention, further comprising a display section for indicating the detection result of the buried object. The control unit controls the display unit to mark and display the portion of the buried object determined to exist between the maximum peak and the minimum peak of the graph.
Thus, the detected position of the buried object in the scanning direction is marked on the display screen of the display unit, so that the user can visually recognize the position of the buried object.

A buried object detection device according to a fifth aspect of the present invention is the buried object detection device according to the fourth aspect of the invention, wherein the wheels are attached to the main body and rotate while being in contact with the surface of the object; and a rotation detection unit provided in the vehicle, connected to the wheel, and detecting information about the rotation of the wheel. The control unit controls the display unit so as to display the dimension of the buried object calculated from the number of rotations of the wheel acquired from the rotation detection unit.
As a result, for example, on the display screen of the display unit, the part where the buried object is detected is marked and displayed, and the size of the buried object in the scanning direction is adjusted based on the number of rotations of the wheels obtained from the rotation detection unit such as an encoder. can be displayed.

A buried object detection device according to a sixth aspect of the invention is the buried object detection device according to any one of the first to fifth aspects, wherein data on the number of steps and reflected waves for each predetermined thickness of the object is obtained. and a storage unit for storing a reference table indicating the relationship between the The control unit compares the data in the reference table with the measured values received by the receiving unit to determine which of the predetermined thicknesses the object corresponds to.

Here, for example, when a gypsum board is used as an object, the thickness of the gypsum board is limited to several types (12.5 mm, 25 mm, etc.) according to standards and the like.
As a result, by storing the reference table obtained when scanning a gypsum board of any thickness (for example, 25 mm) in the storage unit, the data obtained as actual measurements and the data of the reference table can be combined. The thickness of the object can be determined according to whether or not it is approximated by comparing.

A buried object detection apparatus according to a seventh aspect of the present invention is the buried object detection apparatus according to the sixth aspect of the invention, wherein the controller determines that the maximum or minimum peak of the graph obtained as a result of differentiation processing of the received waveform is a predetermined value. If the threshold value is exceeded, the data in the reference table and the measured value received by the receiver are again compared to determine which of the predetermined thicknesses the object corresponds to.
In determining the thickness of an object such as a gypsum board, if the maximum or minimum peak indicating that the end of the object whose permittivity is close to the object is detected, the object and the buried object Since it is assumed that the scanning is started from the position where .
As a result, the once determined thickness of the target object is determined again after the peak is detected, thereby preventing erroneous thickness determination due to starting scanning from the position where the target object and the buried object overlap. can be prevented.

A buried object detection device according to an eighth invention is the buried object detection device according to any one of the first to seventh inventions, wherein the buried object is wood and the object is gypsum board or plywood. be.
As a result, in a combination of gypsum board or plywood, which is a material with a relatively low dielectric constant, and wood, even when detecting the position of the wood while scanning the gypsum board or plywood, the boundary (edge) of the wood can be detected as described above. part) can be accurately detected and the position of the wood under the gypsum board or plywood can be accurately grasped.

A buried object detection method according to a ninth aspect of the present invention is a buried object detection method using a buried object detection apparatus for detecting a buried object in an object using data on reflected waves of electromagnetic waves radiated toward the object. It comprises a radiation step, a delay time setting step, a receiving step, and a detecting step. The radiating step radiates electromagnetic waves from the radiating section. The delay time setting step sets the delay time of the sampling pulse for sampling the reflected wave. In the receiving step, the receiving unit receives the reflected wave of the electromagnetic wave based on the delay time set in the delay time setting step. The detecting step detects an embedded object in the object based on the result of differentiating the received waveform created by integrating one line of sampling data of the reflected wave received in the receiving step.

Here, in an embedded object detection method using an embedded object detection device for detecting an embedded object in an object using data on reflected waves of electromagnetic waves radiated toward the object, the reflected wave received by the receiving unit is An embedded object in the object is detected based on the result of differentiating the received waveform created by integrating the sampling data for one line.
Here, the buried object detected by this buried object detection device is, for example, wood placed inside the gypsum board as the object. It is possible to consider materials that

As a result, by using the result of differential processing of the received waveform, it is possible to detect the difference in an object with a small difference in dielectric constant, such as wood in a gypsum board, which cannot be detected from the data obtained by integrating the sampling data for one line. can be accurately detected by removing the offset component.

A buried object detection method according to a tenth aspect of the invention is the buried object detection method according to the ninth aspect of the invention, wherein in the detection step, the maximum or minimum peak of a graph obtained as a result of differentiation processing of the received waveform is a predetermined value. If the threshold is exceeded, it is determined that the end of the buried object has been detected.
As a result, depending on whether the maximum or minimum peak of the graph obtained by differentiating the received waveform exceeds a predetermined threshold value, for example, the edge of the buried object existing inside the object and the air Boundaries can be detected.
It should be noted that the threshold used for detecting the edge of the buried object may be changed according to, for example, the combination of the object and the buried object, the material, the thickness, and the like.

A buried object detection method according to an eleventh aspect of the present invention is the buried object detection method according to the tenth aspect, wherein in the detection step, it is determined that the buried object exists between the maximum peak and the minimum peak of the graph. do.
By detecting the maximum peak and the minimum peak of the graph obtained by differentiating the received waveform, it is possible to accurately detect the position of the buried object in the scanning direction of the buried object detection device. be able to.

A buried object detection method according to a twelfth aspect of the invention is the buried object detection method according to the eleventh aspect of the invention, wherein the part of the buried object determined to exist between the maximum peak and the minimum peak of the graph is marked. The method further comprises a display step of controlling a display to display the detection result of the implant.
Thus, the detected position of the buried object in the scanning direction is marked on the display screen of the display unit, so that the user can visually recognize the position of the buried object.

A buried object detection method according to a thirteenth aspect of the invention is the buried object detection method according to the twelfth aspect of the invention, wherein in the display step, a rotation detection unit for detecting information about rotation of a wheel attached to the buried object detection device detects The display unit is controlled so as to display the dimensions of the buried object calculated from the obtained number of rotations of the wheel.
As a result, for example, on the display screen of the display unit, the part where the buried object is detected is marked and displayed, and the size of the buried object in the scanning direction is adjusted based on the number of rotations of the wheels obtained from the rotation detection unit such as an encoder. can be displayed.

A buried object detection method according to a fourteenth aspect of the invention is the buried object detection method according to any one of the ninth to thirteenth inventions, wherein data of the number of steps and reflected waves for each predetermined thickness of the object is It further comprises a thickness determination step of comparing the data of the reference table indicating the relationship between and the actual measurement value received by the receiver to determine which of the predetermined thicknesses the object corresponds to.
Here, for example, when a gypsum board is used as an object, the thickness of the gypsum board is limited to several types (12.5 mm, 25 mm, etc.) according to standards and the like.
As a result, by storing the reference table obtained when scanning a gypsum board of any thickness (for example, 25 mm) in the storage unit, the data obtained as actual measurements and the data of the reference table can be combined. The thickness of the object can be determined according to whether or not it is approximated by comparing.

A buried object detection method according to a fifteenth aspect of the invention is the buried object detection method according to the fourteenth aspect of the invention, wherein in the thickness determination step, the maximum or minimum peak of the graph obtained as a result of differentiating the received waveform is When the predetermined threshold value is exceeded, the data of the reference table and the actual measurement value received by the receiving unit are compared again to determine which of the predetermined thicknesses the object corresponds to.

In determining the thickness of an object such as a gypsum board, if the maximum or minimum peak indicating that the end of the object whose permittivity is close to the object is detected, the object and the buried object Since it is assumed that the scanning is started from the position where .
As a result, the once determined thickness of the target object is determined again after the peak is detected, thereby preventing erroneous thickness determination due to starting scanning from the position where the target object and the buried object overlap. can be prevented.

A buried object detection method according to a sixteenth invention is the buried object detection method according to any one of the ninth to fifteenth inventions, wherein the buried object is wood and the object is a gypsum board.
As a result, in a combination of gypsum board, which is a substance with a relatively low dielectric constant, and wood, even when the position of the wood is detected while scanning the gypsum board, the boundary (edge) of the wood can be accurately detected as described above. It is possible to accurately grasp the position of the wood under the gypsum board.

According to the buried object detection apparatus of the present invention, even when the difference in dielectric constant between the object and the buried object is small, the buried object can be detected with high accuracy.

1 is a perspective view showing the configuration of an embedded object detection device according to an embodiment of the present invention; FIG. FIG. 2 is a block diagram showing the configuration of the buried object detection device of FIG. 1; FIG. 3 is a block diagram showing the configuration of an impulse control module in FIG. 2; FIG. FIG. 4 is a diagram showing reflected wave data acquired by the MPU of FIG. 3 ; 3 is a block diagram showing the configuration of a main control module in FIG. 2; FIG. FIG. 2 is a schematic diagram showing a state in which the embedded object detection device in FIG. 1 scans over the wood placed under the gypsum board. FIG. 2 is a diagram showing an A-mode waveform received by the receiving antenna of the buried object detection apparatus of FIG. 1; FIG. 8 is a diagram showing a graph obtained by integrating digital values of the A-mode waveform of FIG. 7; FIG. 9 is a diagram showing the relationship between the calculation result obtained by differentiating the waveform of FIG. 8 and the position of the buried object detection device; FIG. 2 is a view showing a display screen displayed on the display unit of the buried object detection device of FIG. 1; FIG. 2 is a diagram showing a type table of lumber as an embedded object detected by the embedded object detection device of FIG. 1; FIG. 4 is a diagram showing reference data for two types of gypsum boards with different thicknesses as objects. FIG. 13 is a diagram showing a reference table for a gypsum board with a thickness of 25 mm among the gypsum boards in FIG. 12; FIG. 2 is a flow chart showing the flow of processing of an embedded object detection method performed by the embedded object detection apparatus of FIG. 1; FIG. FIG. 2 is a flow chart showing the flow of processing of an embedded object detection method performed by the embedded object detection apparatus of FIG. 1; FIG. FIG. 2 is a flow chart showing the flow of processing of an embedded object detection method performed by the embedded object detection apparatus of FIG. 1; FIG. 2 is a flow chart showing the flow of processing for determining the type of gypsum board carried out by the buried object detection apparatus of FIG. 1;

A buried object detection device 1 and a buried object detection method according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 17. FIG.
FIG. 1 is a perspective view showing a state in which a buried object detection device 1 of this embodiment is placed on concrete (object) 100. FIG. FIG. 2 is a block diagram showing a schematic configuration of the buried object detection device 1 of this embodiment.

(1-1. Configuration of buried object detection device 1)
First, the principle of detecting an embedded object in an object by the embedded object detection device 1 of the present embodiment will be described by taking an example using concrete 100 as the object and a reinforcing bar as the embedded object 101 .
The buried object detection apparatus 1 of this embodiment radiates impulse waves (electromagnetic waves) toward the concrete 100 while moving on the surface 100a of an object such as the concrete 100, and receives and analyzes the reflected waves. The positions of the buried objects 101a, 101b, 101c and 101d in the concrete 100 are detected. In FIG. 1, the direction of movement of the buried object detection device 1 is indicated by an arrow A. As shown in FIG.

In the example shown in FIG. 1, the buried objects 101a, 101b, 101c, and 101d are reinforcing bars, and are buried at depths of 20 cm, 15 cm, 10 cm, and 5 cm from the surface 100a of the concrete 100, respectively. . In FIG. 1, an arrow B indicates the depth direction of the concrete 100, and an arrow C indicates the opposite direction (surface direction).
The four reinforcing bars (embedded objects 101a to 101d) embedded in the concrete 100 are arranged in a direction substantially parallel to the surface 100a of the concrete 100 and in a direction intersecting the movement direction of the buried object detection device 1. It is

As shown in FIG. 2, the buried object detection device 1 includes a main body 2, a handle 3, four wheels 4, an impulse control module 5, a main control module 6, an encoder (rotation detector) 7, A display unit 8 is provided.
The handle 3 is a handle portion that is gripped by an operator (user), and is provided on the upper surface of the main body portion 2 . The four wheels are rotatably attached to the lower portion of the body portion 2 . When detecting the buried object 101 inside the concrete 100 , the operator grips the handle 3 and rotates the wheel 4 to move the buried object detection device 1 on the surface 100 a of the concrete 100 .

The impulse control module 5 controls the timing of radiating the impulse wave toward the surface 100a of the concrete 100, the timing of receiving the reflected wave of the radiated impulse wave, and the like.
The encoder 7 is connected to the wheels 4 and detects information about the rotation of the wheels 4. Based on the detected information, the impulse control module 5 is informed of the impulse wave emission timing and the reflected wave reception timing. to send signals to control the

The main control module 6 receives data on the reflected wave received by the impulse control module 5 and detects the buried object 101 .
The display section 8 is provided on the upper surface of the main body section 2 and displays an image or the like indicating the positions of the buried objects 101a, 101b, 101c, and 101d.

(1-2. Impulse control module 5)
FIG. 3 is a block diagram showing the configuration of the impulse control module 5. As shown in FIG.
The impulse control module 5 includes, as shown in FIG. 15, a high-speed sample and hold circuit 16, an A/D converter 17, and a storage section 18.
The control unit 10 is configured by an MPU (Micro Processing Unit) or the like, and commands an impulse generation circuit 13 to generate an impulse wave using an encoder input as a trigger.

The control unit 10 also controls the delay IC 14 that adjusts the sampling pulse that sets the timing and period for receiving the reflected wave in the receiving antenna 12 .
The transmitting antenna 11 is provided on the bottom side of the main body 2 and radiates an impulse wave with a constant period based on the pulse period.
The receiving antenna 12 is provided on the bottom side of the main body 2 and mainly receives reflected waves of impulse waves radiated from the transmitting antenna 11 . Specifically, for example, if the impulse wave radiated from the transmitting antenna 11 takes 5 ns (=5000 ps) to make a round trip in the concrete 100, the receiving antenna 12 receives the impulse wave 5 ns after the impulse wave is radiated from the transmitting antenna 11. By receiving the reflected wave received during (5000 ps), a received waveform as shown in FIG. 4 can be obtained.

The impulse generation circuit 13 is controlled by the control unit 10, and is triggered by the input of the encoder 7 via the control unit 10. Based on the command from the MPU, the impulse generation circuit 13 generates an impulse wave a predetermined number of times at a predetermined time interval. (For example, 500 times at intervals of 10 ps) and output to the transmitting antenna 11 .
The delay IC 14 is controlled by the control unit 10 and sets the delay time and sampling period of the sampling pulse for sampling the reflected wave at the receiving antenna 12 by a digital signal.

The sampling pulse generation circuit 15 transmits sampling pulses to the high-speed sample/hold circuit 16 based on the delay time set by the delay IC 14 so as to capture the reflected wave received by the receiving antenna 12 .
The high-speed sample-and-hold circuit 16 receives the sampling pulse from the sampling pulse generation circuit 15 , captures the reflected wave received by the receiving antenna 12 , and transmits it to the A/D converter 17 .

The A/D converter 17 A/D (Analog/Digital) converts the signal of the reflected wave received from the high-speed sample-and-hold circuit 16 and transmits it to the control unit 10 .
The storage unit 18 is connected to the control unit 10 and stores sampling data corresponding to one line received by the receiving antenna 12, for example, 0 to 511 steps. Further, the storage unit 18 stores a wood type table, a reference table for determining the thickness of a gypsum board, and the like, which will be described later.

In the embedded object detection apparatus 1 of the present embodiment, the impulse control module 5 outputs impulse waves from the transmission antenna 11 multiple times with the input from the encoder 7 as a trigger. Then, the impulse control module 5 uses the delay IC 14 to set the delay time after the impulse wave is radiated, and delays the acquisition timing of the reflected wave to obtain the reflected wave for each distance from the surface 100a of the concrete 100. data can be obtained.

Here, FIG. 4 is a diagram showing reflected wave data acquired by the MPU. On the vertical axis, the received reflected wave is A/D converted with a resolution of 2 to the 12th power, and digital data of 0 to 4095 gradations are shown with the median value of 2048 gradations as the axis O, and the arrow direction is negative. showing the side. The horizontal axis indicates the distance from the receiving antenna 12, and the arrow direction (corresponding to the depth direction B) indicates the longer distance from the receiving antenna 12. FIG. A long distance corresponds to a large depth.

In addition, since the waveform W1 shown in FIG. 4 also includes reflected waves (such as p1) that are reflected by the antenna without being radiated into the concrete 100, by calculating the difference from the reference waveform, Changes in reflected wave data are extracted.
The data shown in FIG. 4 is data indicating the strength of the received signal from the time when the encoder 7 receives the input until the time when the encoder 7 receives the next input. By gradually delaying the acquisition timing of the reflected wave based on the delay time set by the delay IC 14, the reflected wave from a position at a long distance from the receiving antenna 12 is received. , the reception timing delay is undone and the reception timing is gradually delayed again. That is, a reflected wave in the depth direction B at a predetermined measurement position (the position where the input from the encoder 7 is received) in the moving direction A is received. The data of the reflected wave received from the input of the encoder 7 shown in FIG. 4 until the next input of the encoder is called data for one line. The control unit 10 transmits RF (Radio Frequency) data for one line to the main control module 6 every time data for one line is accumulated.

Since the buried object detection apparatus 1 is moved on the surface 100a of the concrete 100 by the operator (user), the measurement position is not strictly the same position, and the depth direction B is also relative to the surface 100a of the concrete 100. not strictly perpendicular.

(1-3. Main control module 6)
FIG. 5 is a block diagram showing the configuration of the main control module 6. As shown in FIG.
The main control module 6, as shown in FIG. .
The receiving unit 21 receives one line of RF data each time it is transmitted from the control unit 10 of the impulse control module 5 .
The RF data management unit 22 stores one line of RF data received by the receiving unit 21 .

The buried object determination unit 24 uses the RF data for one line stored in the RF data management unit 22 to determine the presence or absence of the buried object 101 and to detect the position of the buried object 101 .
The processing for detecting the buried object 101 in the buried object determination unit 24 may be performed using a known method based on a plurality of one-line RF data received by the receiving antenna 12 . Specifically, for example, when the buried object 101 is metal such as a reinforcing bar, the impulse wave radiated from the transmitting antenna 11 is reflected at the interface due to the difference in dielectric constant between the concrete 100 and the metal. . Therefore, by detecting the speed (intensity) of the reflected wave reflected at the interface of the buried object 101 and the time until the reflected wave is received by the receiving antenna 12, the buried object in the concrete 100 can be detected. The presence or absence of 101 and its position can be detected.

The determination result registration unit 25 registers the position of the buried object 101 detected by the buried object determination unit 24 in the RF data management unit 22 .
The display control unit 26 displays an image obtained by performing color gradation processing on the signal intensity on the plane of the movement direction A and the depth direction B, markings indicating the position of the buried object 101, the dimensions of the buried object 101 in the scanning direction, and the like. Thus, the display unit 8 is controlled.

<Detection of buried object in object with small difference in dielectric constant>
As shown in FIG. 6, the buried object detection apparatus 1 of this embodiment scans the surface of the gypsum board (object) 110 to detect the wood (buried object) 111 placed inside the gypsum board 110. .
Here, since both the gypsum board 110 and the wood 111 are materials with relatively low dielectric constants, the difference in dielectric constant between the gypsum board 110 and the wood 111 is small in a general buried object detection method. However, it was difficult to detect buried objects based on changes in received waveforms of reflected waves.

The relative dielectric constant of each material is, for example, wood 2 to 6, gypsum board 2 to 6, plywood 2 to 6, dry concrete 6 to 8, wet concrete 8 to 20, reinforcing bar (metal), assuming that air is 1. Infinite.
That is, when the buried object detection apparatus 1 scans a gypsum board 110 having a thickness of 9 mm, a waveform called an A-mode waveform shown in FIG. 7 is obtained. Then, the digital values of the A-mode waveform shown in FIG. 7 are integrated for each line to obtain a graph showing changes in the digital values for the lines shown in FIG.

Here, for example, in a combination with a large difference in dielectric constant, such as the above-described reinforcing bars (embedded object 101) in the concrete 100, the reflected wave at the interface of materials with different dielectric constants is detected. can be detected.
However, in the graph shown in FIG. 8, since the difference in dielectric constant between the gypsum board 110 and the wood 111 is small, the reflected wave at the end of the wood (column) 111 placed inside the gypsum board 110 with a thickness of 9 mm changes in intensity (digital value) do not appear clearly, and it is difficult to accurately detect the position of the wood 111 .

Therefore, in the buried object detection apparatus 1 of the present embodiment, the control unit 10 differentiates the received waveform (see FIG. 8) created by integrating sampling data for one line of the reflected wave received by the receiving antenna 12. process. Then, the control unit 10 detects the wood (buried object) 111 in the gypsum board (object) 110 based on the result of the differentiation processing.
Specifically, the control unit 10 differentiates the received waveform (see FIG. 8) created by integrating the sampling data for one line of the reflected wave. is used to detect the edge of the wood 111 placed inside the gypsum board 110 .

In the graph shown in FIG. 9, when the buried object detection device 1 approaches the wood 111 from the air portion inside the gypsum board 110 and moves to the boundary portion from the air to the wood 111, the negative side A peak value appears that exceeds the threshold of . Then, when the buried object detection device 1 moves to the boundary portion where the wood 111 transitions to the air, a peak value exceeding the plus side threshold appears.

As a result, by detecting at least one of the peak value on the negative side and the peak value on the positive side of the graph obtained by differentiating the received waveform created by integrating the sampling data for one line of the reflected wave, The end face of the wood 111 can be detected by removing the offset component.
Furthermore, when the peak values on the negative side and the positive side are detected, it can be determined that the wood 111 exists between the peak values.

Note that in the graph shown in FIG. 9, between the peak values on the minus side and the plus side that exceed the threshold values on the minus side and the plus side, there is a point of change from plus to minus due to the material of the wood 111 and the minus point. A point of change from to plus appears. However, in the present embodiment, not only is the peak value detected from the graph obtained by differentiating the data in FIG. Detect the value as the edge of the wood 111 .

As a result, even if peaks occur in the graph after differential processing due to changes in the received waveform of the reflected wave due to the grain of the wood 111, etc., these peak values are prevented from being detected as the edge of the wood 111. can do.

<Marking display control accompanying detection of buried objects>
Furthermore, in the buried object detection device 1 of this embodiment, the width of the wood 111 detected between the peak value on the negative side and the peak value on the positive side (dimension in the scanning direction of the buried object detection device 1) , the marking process is performed on the display screen of the display unit 8 .
Specifically, as shown in FIG. 10, the control unit 10 performs marking processing (bold line portion) on the display screen of the display unit 8 between the peak values of the minus side and the plus side where the wood 111 is detected. The display unit 8 is controlled as follows.
This allows the operator to visually recognize in which part in the scanning direction the buried object (wood 111) is located.

Furthermore, in the buried object detection apparatus 1 of the present embodiment, the control unit 10 calculates the width (dimension in the scanning direction) of the wood 111 based on the rotation speed of the wheel 4 obtained from the encoder 8 . Then, as shown in FIG. 10, the control unit 10 controls the display unit 8 so as to display the calculated width (dimension in the scanning direction) of the wooden piece 111 in the marked portion where the wooden piece 111 is detected. .

As a result, the operator can recognize the width (dimension in the scanning direction) of the detected wooden piece 111 in addition to the location of the buried object (wood 111) in the scanning direction.
If the operation area displayed on the display screen of the display unit 8 is, for example, 320 lines (±160 lines), the portion between the peak values on the negative side and the positive side where the wood 111 is detected is marked. First, mark the peak value from the threshold-exceeding start line to the threshold-exceeding end line.

Here, if there are a plurality of peak values from the threshold-exceeding start line to the threshold-exceeding end line, only one point of the peak value on the side closer to the negative peak is marked.
Also, when marking the peak value from the starting line of exceeding the threshold on the negative side to the ending line of exceeding the threshold, if there are multiple peak values, mark only one peak value on the side closer to the positive peak. do.
Then, if the minimum/maximum line of the lines in the detection range exceeds the threshold value, the lines with the minimum/maximum values up to that point are marked.
Thereby, on the display screen of the display unit 8, the marking process can be performed on the portion where the wood 111 is detected.

<Determination of type of wood (buried object)>
Also, the control unit 10 can recognize the thickness of the wood (buried material) 111 based on the distance in the depth direction between the x points obtained from the A-mode waveform shown in FIG. Therefore, the control unit 10 refers to the wood type table shown in FIG. 11 using the width (dimension in the scanning direction) of the wood 111 detected by the determination process and the thickness obtained from the A-mode waveform of FIG. , the type of wood 111 (square lumber or plate) can be easily determined.

Here, by using the lumber type table shown in FIG. ), it is possible to determine which of the four types (square lumber, plate 1, plate 2, and plate 3).
Note that the lumber type table shown in FIG. 11 is stored in the storage unit 18 in advance.

<Type determination of gypsum board (object)>
Furthermore, in the buried object detection apparatus 1 of the present embodiment, the thickness of the gypsum board 110 as an object is limited to several types by standards and the like. make a judgment.
Specifically, for example, if the gypsum board 110 being used has two thicknesses of 12.5 mm (solid line) and 25.0 mm (solid line connecting square points), each thickness As shown in FIG. 12, the received waveform of the reflected wave obtained by scanning the gypsum board 110 on the gypsum board 110 has a difference in the minimum value data appearing at a specific number of steps (near 90 steps, etc.), as shown in FIG. occurs.

The storage unit 18 stores in advance a reference table showing data of reflected waves of a gypsum board 110 having a thickness of 25 mm shown in FIG.
Therefore, as an initial setting value, for example, scanning is started in a mode for scanning a gypsum board 110 having a thickness of 12.5 mm, and the measurement result of the reflected wave is compared with the value of each step in the reference table of FIG. , the thickness of the gypsum board 110 can be determined according to whether the thickness of the scanned gypsum board 110 approximates the reference data of 25.0 mm.

<Flow of buried object detection method>
In the buried object detection method of this embodiment, the above-described buried object detection apparatus 1 is used to scan gypsum boards 110 having thicknesses of 12.5 mm and 25.0 mm, for example, according to the flowchart shown in FIG. , the wood 111 in the gypsum board 110 is detected.
That is, in step S11, it is determined whether or not the operator has selected the manual mode for selecting the thickness of the gypsum board 110 . In this manual mode, when the operator recognizes the thickness of the gypsum board 110 in advance, the recognized thickness is manually selected.

Here, when the manual mode is selected, since the operator has already recognized the thickness of the gypsum board 110, the process proceeds to step S19. On the other hand, if the manual mode has not been selected, the process proceeds to step S12 in order to carry out an automatic selection mode for automatically selecting the thickness of the gypsum board 110 .
Next, in step S12, since the manual mode was not selected in step S11, the control unit 10 first detects that the buried object detection device 1 is traveling on the surface of the gypsum board 110, so that the encoder 7 to get encoder pulses.

Next, in step S<b>13 , after obtaining the encoder pulse, the control unit 10 turns on the delay IC 14 and controls the impulse generation circuit 13 to cause the transmission antenna 11 to start emitting an impulse wave.
Next, in step S14, the control unit 10 uses the sampling pulse output from the sampling pulse generation circuit 15 based on the delay time of the delay IC 14 to sample the waveform of the reflected wave from steps 0 to 511 at high speed. It controls the sample and hold circuit 16 .

Next, in step S15, the control unit 10 causes the storage unit 18 to store the sampled data of steps 0 to 511. FIG.
Next, in step S<b>16 , the control unit 10 performs a type (thickness) determination process for the gypsum board 110 .
The type determination processing of the gypsum board 110 in step S16 will be described later in detail using the flowchart of FIG.

Next, in step S17, the control unit 10 determines whether or not the result of the type determination in step S16 is the gypsum board 110 with a thickness of 25 mm, which is the initial setting.
Here, if the thickness is determined to be 25 mm, the process proceeds to step S18. On the other hand, when it is determined that the thickness is not 25 mm, it is determined that the gypsum board 110 is 12.5 mm thick, and the wood 111 for the 12.5 mm thick gypsum board 110 is detected. Proceed to the flow chart of .

Next, in step S18, since it was determined in step S17 that the gypsum board 110 has a thickness of 25.0 mm, the control unit 10 selects 0 out of the sampling data from steps 0 to 511 stored in the storage unit 18. Integrate the data in the range up to 120 steps, and proceed to the flow chart of FIG.
The reason for using data within the range of 0 to 120 steps for the 25.0 mm mode is that the number of steps was adjusted according to the thickness of the gypsum board 110 of 25.0 mm.

Next, in step S19, since the manual mode was selected in step S11, the control unit 10 determines whether or not the operator has selected the 12.5 mm mode in the manual mode.
Here, when the 12.5 mm mode is selected, the process proceeds to step S20 in order to perform detection processing of wood 111 for gypsum board 110 with a thickness of 12.5 mm. On the other hand, if the 12.5 mm mode has not been selected, it is determined that the 25.0 mm mode has been selected, and the process proceeds to step S26 in order to perform detection processing of the wood 111 for the gypsum board 110 with a thickness of 25.0 mm. move on.

Next, at step S20, the controller 10 sets the 12.5 mm mode.
Next, in step S21, since the 12.5 mm mode was selected in step S20, the control unit 10 first detects that the buried object detection device 1 is traveling on the surface of the gypsum board 110 by 7 to get encoder pulses.
Next, in step S<b>22 , after obtaining the encoder pulse, the control unit 10 turns on the delay IC 14 and controls the impulse generation circuit 13 to start the transmission antenna 11 to emit an impulse wave.

Next, in step S23, the control unit 10 uses the sampling pulse output from the sampling pulse generation circuit 15 based on the delay time of the delay IC 14 to sample the waveform of the reflected wave from steps 0 to 511 at high speed. It controls the sample and hold circuit 16 .
Next, in step S24, the control unit 10 causes the storage unit 18 to store the sampled data of steps 0 to 511. FIG.

Next, in step S25, the control unit 10 integrates the data within the range of 0 to 110 steps among the data of 0 to 511 steps stored in the storage unit 18 as control for the 12.5 mm mode. After processing, proceed to the flow chart of FIG.
The reason for using data within the range of 0 to 110 steps for the 12.5 mm mode is that the number of steps was adjusted according to the thickness of the gypsum board 110 of 12.5 mm.

Similarly, at step S26, the controller 10 sets the 25.0 mm mode.
Next, in step S27, since the 25.0 mm mode was selected in step S26, the control unit 10 first detects that the buried object detection device 1 is traveling on the surface of the gypsum board 110 by 7 to get encoder pulses.
Next, in step S28, after obtaining the encoder pulse, the control unit 10 turns on the delay IC 14 and controls the impulse generation circuit 13 to cause the transmission antenna 11 to start emitting an impulse wave.

Next, in step S29, the control unit 10 uses the sampling pulse output from the sampling pulse generation circuit 15 based on the delay time of the delay IC 14 to sample the waveform of the reflected wave from steps 0 to 511 at high speed. It controls the sample and hold circuit 16 .
Next, in step S30, the control unit 10 causes the storage unit 18 to store the sampled data of steps 0 to 511. FIG.

Next, in step S25, the control unit 10 integrates the data within the range of 0 to 120 steps among the data of 0 to 511 steps stored in the storage unit 18 as control for the 25.0 mm mode. After processing, proceed to the flow chart of FIG.
Next, the processing when it is determined that the thickness is not 25.0 mm as the automatic selection mode in step S17 will be described below using the flowchart of FIG.

That is, in step S41, since it was determined in step S17 that the 25.0 mm mode was not selected, the control unit 10 selects the 12.5 mm mode in the automatic selection mode. Then, the control unit 10 first acquires an encoder pulse from the encoder 7 in order to detect that the buried object detection device 1 is running on the surface of the gypsum board 110 .
Next, in step S<b>42 , after obtaining the encoder pulse, the control unit 10 turns on the delay IC 14 and controls the impulse generation circuit 13 to start the transmission antenna 11 to emit an impulse wave.

Next, in step S43, the control unit 10 uses the sampling pulse output from the sampling pulse generation circuit 15 based on the delay time of the delay IC 14 to sample the waveform of the reflected wave from steps 0 to 511 at high speed. It controls the sample and hold circuit 16 .
Next, in step S44, the control unit 10 causes the storage unit 18 to store the sampled data of steps 0 to 511. FIG.

Next, in step S45, the control unit 10 integrates the data within the range of 0 to 110 steps among the data of 0 to 511 steps stored in the storage unit 18 as control for the 12.5 mm mode. process.
Next, in step S46, the control unit 10 subtracts the integrated data before and after scanning.

Next, in step S47, the control unit 10 performs moving average processing on eight lines of difference data to create a graph shown in FIG.
Next, in step S48, the control unit 10 causes the storage unit 18 to store all of the peaks exceeding the negative threshold value and the peaks exceeding the positive threshold value in the graph shown in FIG.
Next, in step S49, the control unit 10 targets all the peak results stored in the storage unit 18, and proceeds to step S50.

Next, in step S<b>50 , the control unit 10 determines whether two adjacent peaks have changed from negative to positive for all peak results stored in the storage unit 18 .
Here, when the two adjacent peaks change from minus to plus, the process proceeds to step S51. On the other hand, if the two adjacent peaks have not changed from negative to positive, the process proceeds to step S52.

Next, in step S51, since it is determined in step S50 that two adjacent peaks have changed from negative to positive, the control unit 10 determines that there is wood 111 between these two peaks, Wood 111 is detected.
Next, in step S52, the control unit 10 repeats step Processing from S49 to step S52 is performed.

Next, in step S53, for all the peak results stored in the storage unit 18 in step S52, since the determination of whether or not two adjacent peaks have changed from negative to positive has been completed, the control unit 10 In order to visually recognize that the wood 111 exists between the two detected peaks, the marking display process shown in FIG. 10 is performed on the display screen of the display unit 8 .

At this time, as described above, the width (dimension in the scanning direction) of the wood 111 may also be displayed on the display screen.
After the process of step S53 is completed, when an encoder pulse is input next, the process proceeds to step S12 of FIG. 14 again, and the process described above is performed.
Next, in step S18, when it is determined that the thickness is 25.0 mm as the automatic selection mode, and in steps S25 and S31, it is determined that the thickness is 12.5 mm and 25.0 mm as the manual mode. The processing in this case will be described below with reference to the flowchart of FIG.

That is, in step S61, the control unit 10 subtracts the integrated data before and after scanning.
Next, in step S62, the control section 10 performs moving average processing on eight lines of difference data to create a graph shown in FIG.
Next, in step S63, the control unit 10 causes the storage unit 18 to store all of the peaks exceeding the negative threshold value and the peaks exceeding the positive threshold value in the graph shown in FIG.

Next, in step S64, the control unit 10 targets all the peak results stored in the storage unit 18, and proceeds to step S65.
Next, in step S<b>65 , the control unit 10 determines whether two adjacent peaks have changed from negative to positive for all peak results stored in the storage unit 18 .
Here, when the two adjacent peaks change from minus to plus, the process proceeds to step S66. On the other hand, if the two adjacent peaks have not changed from negative to positive, the process proceeds to step S67.

Next, in step S66, since it was determined in step S65 that the two adjacent peaks changed from negative to positive, the control unit 10 determines that there is wood 111 between these two peaks, Wood 111 is detected.
Next, in step S67, the control unit 10 repeats step Processing from S64 to step S67 is performed.

Next, in step S68, for all the peak results stored in the storage unit 18 in step S67, it has been determined whether two adjacent peaks have changed from negative to positive. In order to visually recognize that the wood 111 exists between the two detected peaks, the marking display process shown in FIG. 10 is performed on the display screen of the display unit 8 .

Also here, as described above, the width of the wood 111 (dimension in the scanning direction) may be displayed on the display screen.
After the process of step S68 is completed, when an encoder pulse is input next, the process proceeds to step S12 of FIG. 14 again, and the process described above is performed.
In the buried object detection method of this embodiment, as described above, the buried object detection device 1 that detects the wood 111 in the gypsum board 110 using the data on the reflected wave of the impulse wave emitted toward the gypsum board 110 is used. The buried object detection method includes a radiation step, a delay time setting step, a reception step, and a detection step. The radiation step radiates an impulse wave from the transmission antenna 11 . In the delay time setting step, the delay IC 14 sets the delay time of the sampling pulse for sampling the reflected wave. The receiving step receives the reflected wave of the impulse wave at the receiving antenna 12 based on the delay time set in the delay time setting step. The detecting step detects the wood 111 in the gypsum board 110 based on the result of differentiating the received waveform created by integrating the sampling data for one line of the reflected wave received in the receiving step.

Here, as the buried object detected by this buried object detection method, as described above, for example, the wood 111 placed inside the gypsum board 110 as the object, and the object and the buried object are relatively large. , a combination of materials with a small difference in dielectric constant.
As a result, by using the result of differential processing of the received waveform, an object with a small difference in dielectric constant, such as the wood 111 in the gypsum board 110, which cannot be detected from the data obtained by integrating the sampling data for one line An embedded object within an object can be accurately detected by removing the offset component.

<Type Determining Process of Gypsum Board 110>
In the buried object detection method of the present embodiment, in step S16 of FIG. 14, the type is determined based on the thickness of the gypsum board 110 scanned by the buried object detection apparatus 1 at present.
In the buried object detection method of the present embodiment, a process for discriminating between two types of gypsum boards 110 having a thickness of 12.5 mm and 25.0 mm will be described below.

That is, the determination of the type of gypsum board 110 in step S16 is performed according to the flowchart of FIG.
First, in step S71, the control unit 10 obtains a moving average of reception intensity data of reflected waves from the time when an encoder pulse is obtained from the encoder 7 to the ninth line.
Here, the reason why the moving average of the data from the acquisition of the encoder pulse to the 9th line is acquired is to suppress the influence such as distortion of the data as the actual measurement value due to the influence of noise or the like as much as possible.

Next, in step S72, the control unit 10 refers to the reference data table of the gypsum board 110 having a thickness of 25.0 mm shown in FIG. .
Next, in step S73, the control unit 10 compares the minimum value of the data included in the reference table shown in FIG. It is determined whether the difference is within 80.

That is, in step S73, it is determined whether or not the difference between the actually measured data and the 25.0 mm reference table stored in the storage unit 18 is equal to or greater than a predetermined value.
Here, if the difference is within 80, the difference from the 25.0 mm reference data is small, so the process proceeds to step S74. Therefore, the process proceeds to step S78, the thickness of the gypsum board 110 is determined to be 12.5 mm, and the process ends.

Next, in step S74, the control unit 10 raises the 25 mm flag 1 in order to provisionally determine the thickness of the gypsum board 110. FIG.
Next, in step S75, the control unit 10 obtains a moving average of data from the line exceeding the positive threshold to the ninth line.
Here, the reason for using the moving average of the data from the line exceeding the positive threshold to the 9th line is that when the buried object detection apparatus 1 scans from the position where the wood 111 and the gypsum board 110 overlap, This is to detect the boundary portion where the wood 111 inside the gypsum board 110 shifts from the portion where the wood 111 exists inside the gypsum board 110 to the air portion, and to acquire the actual measurement value after passing through the wood 111 portion.

Next, in step S76, the control unit 10 again compares the minimum value of the data contained in the reference table shown in FIG. 13 with the minimum value of the moving average up to the 9th line acquired in step S75 , and whether the difference is within 80 or not.
Here, if the difference is within 80, the difference from the 25.0 mm reference data is small, so the process proceeds to step S77. Therefore, the process proceeds to step S79, the thickness of the gypsum board 110 is determined to be 12.5 mm, and the process ends.

Next, in step S77, the control section 10 raises the second 25 mm flag 2 in order to fix the thickness of the gypsum board 110, fixes the thickness to 25.0 mm, and ends the process.
As described above, the buried object detection method of the present embodiment can accurately detect the wood 111 even when the gypsum board 110 and the wood 111 have a relatively small difference in dielectric constant. By performing the type (thickness) determination of the wood, it is possible to further improve the detection accuracy of the lumber.

[Other embodiments]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the invention.

(A)
In the above embodiment, an example has been described in which materials having relatively low dielectric constants, ie, the gypsum board 110 as the object and the wood 111 as the buried object, are used. However, the present invention is not limited to this.
For example, the combination of the object and the buried object may be a combination of other materials with low dielectric constants as described above, and is not limited to materials with low dielectric constants, and materials with similar dielectric constants. It may be a combination of them.

(B)
In the above-described embodiment, an example in which thickness determination is performed in two stages in the type determination processing of the gypsum board 110 has been described. However, the present invention is not limited to this.
For example, the type (thickness) of the gypsum board may be determined only by the determination in step S73 shown in FIG.
However, as described in the above embodiment, if there is a possibility that the scanning start position is the position where the gypsum board and the wood overlap, as in the above embodiment, a two-step determination is made again in step S76. More preferably, a determination is performed.

(C)
In the above embodiment, in order to determine the types of gypsum boards 110 with two types of thickness (12.5 mm and 25.0 mm), only the reference data of 25.0 mm is stored in the storage unit 18, and the reference data and An example has been described in which 25.0 mm is determined when the difference is equal to or less than the predetermined value, and 12.5 mm is determined when the difference from the reference data is equal to or greater than the predetermined value. However, the present invention is not limited to this.
For example, when determining the type of gypsum boards having three or more thicknesses, a reference table for each thickness may be stored in the storage unit.
This makes it possible to perform three or more type determinations.

(D)
In the above embodiment, the moving average from the acquisition of the encoder pulse to the 9th line is used as the actual measurement value acquired when performing the type determination of the gypsum board. However, the present invention is not limited to this.
For example, as the data of the measured values to be compared with the reference table, the measured values of a specific line may be used without using the moving average up to the ninth line.
However, in order to suppress the influence of noise and the like included in the actual measurement values of each line, it is more preferable to use a moving average of multiple lines as in the above embodiment.

(E)
In the above embodiment, an example using an impulse wave as the electromagnetic wave radiated from the transmitting antenna 11 has been described. However, the present invention is not limited to this.
For example, the configuration may be such that the transmitting antenna radiates electromagnetic waves of other forms such as sine waves.

(F)
In the above embodiment, an example of detecting the buried object 101 in the concrete 100 using the buried object detection device 1 having the four wheels 4 attached to the main body 2 has been described. However, the present invention is not limited to this.
For example, the number of wheels attached to the main body is not limited to four, and may be one, two, three, or five or more.

(G)
In the above embodiment, the present invention has been described as an example of the buried object detection device 1 and the buried object detection method. However, the present invention is not limited to this.

For example, the present invention may be implemented as an embedded object detection program that causes a computer to execute each step in the above-described embedded object detection method.
This buried object detection program is stored in the storage unit, and the CPU reads the program stored in the storage unit to cause the hardware to execute each step.
Alternatively, the present invention may be implemented as a recording medium storing this buried object detection program.

The buried object detection apparatus of the present invention can detect various buried objects with high accuracy even when the difference in dielectric constant between the object and the buried object is small. It is widely applicable to devices.

1 buried object detector 2 main body 3 handle 4 wheel 5 impulse control module 6 main control module 7 encoder (rotation detector)
8 display unit 10 control unit 11 transmission antenna (radiating unit)
12 Receiving antenna (receiving part)
13 impulse generation circuit 14 delay IC (variable delay unit)
15 Sampling pulse generation circuit 16 High-speed sample/hold circuit 17 A/D converter 18 Storage unit 21 Reception unit 22 RF data management unit 24 Buried object judgment unit 25 Judgment result registration unit 26 Display control unit 100 Concrete (object)
100a surface 101a-101d buried object 110 gypsum board (object)
111 Wood (buried material)

Claims (16)

An embedded object detection device for detecting an embedded object in an object using data on reflected waves of electromagnetic waves radiated toward the object,
a main body;
a radiating portion provided in the main body portion for radiating the electromagnetic wave;
a receiving unit provided in the main body for receiving the reflected wave of the electromagnetic wave;
a variable delay unit for setting a delay time of a sampling pulse for sampling the reflected wave in the receiving unit;
Reception created by accumulating reflected wave data received from an encoder input to a next encoder input as sampling data for one line of the reflected wave received by the receiving unit a control unit that detects the buried object in the object based on the result of differentiating the waveform;
A buried object detection device with The control unit determines that the end of the buried object is detected when the maximum or minimum peak of the graph obtained as a result of differentiation processing of the received waveform exceeds a predetermined threshold.
The buried object detection device according to claim 1. the control unit determines that the buried object is between the maximum peak and the minimum peak of the graph;
The buried object detection device according to claim 2. further comprising a display unit for indicating the detection result of the buried object,
The control unit controls the display unit to mark and display the portion of the buried object determined to exist between the maximum peak and the minimum peak of the graph.
The buried object detection device according to claim 3. a wheel attached to the main body and rotating in contact with the surface of the object;
a rotation detection unit provided in the main body, connected to the wheel, and configured to detect information related to rotation of the wheel;
further comprising
The control unit controls the display unit to display the size of the buried object calculated from the number of rotations of the wheel acquired from the rotation detection unit.
The buried object detection device according to claim 4. further comprising a storage unit that stores a reference table showing the relationship between the number of steps in which sampling data is acquired for each predetermined thickness of the object and the data of the reflected wave,
The control unit compares the data of the reference table with the measured values received by the receiving unit to determine which of the predetermined thicknesses the object corresponds to.
A buried object detection device according to any one of claims 1 to 5. When the maximum or minimum peak of the graph obtained as a result of differentiation processing of the received waveform exceeds a predetermined threshold value, the control unit re-determines the data of the reference table and the actual measurement value received by the receiving unit. to determine which of the predetermined thicknesses the object corresponds to,
The buried object detection device according to claim 6. The buried object is wood, and the object is gypsum board or plywood,
The buried object detection device according to any one of claims 1 to 7. An embedded object detection method using an embedded object detection device for detecting an embedded object in an object using data on reflected waves of electromagnetic waves radiated toward the object,
a radiating step of radiating the electromagnetic wave from a radiating section;
a delay time setting step of setting a delay time of a sampling pulse for sampling the reflected wave;
a receiving step of receiving a reflected wave of the electromagnetic wave in a receiving unit based on the delay time set in the delay time setting step;
Reception created by accumulating reflected wave data received from an encoder input to a next encoder input as sampling data for one line of the reflected wave received in the receiving step a detection step of detecting the buried object in the object based on the result of differentiating the waveform;
A buried object detection method comprising In the detection step, when the maximum or minimum peak of the graph obtained as a result of differentiation processing of the received waveform exceeds a predetermined threshold, it is determined that the end of the buried object has been detected.
The buried object detection method according to claim 9 . In the detection step, it is determined that the buried object is between the maximum peak and the minimum peak of the graph.
The buried object detection method according to claim 10. a display step of controlling a display section showing the detection result of the buried object so as to mark and display the portion of the buried object determined to exist between the maximum peak and the minimum peak of the graph; rice field,
The buried object detection method according to claim 11 . In the display step, the size of the buried object calculated from the number of revolutions of the wheel acquired from a rotation detection unit that detects information about the rotation of a wheel attached to the buried object detection device is displayed. control the department,
The buried object detection method according to claim 12. Data of a reference table indicating the relationship between the number of steps in which sampling data is acquired for each predetermined thickness of the object and the data of the reflected wave is compared with the actual measurement value received by the receiving unit, and the object is further comprising a thickness determination step of determining which of the predetermined thicknesses corresponds to
The buried object detection method according to any one of claims 9 to 13. In the thickness determination step, when the maximum or minimum peak of the graph obtained as a result of differentiation processing of the received waveform exceeds a predetermined threshold value, the data of the reference table and the actual measurement received by the receiving unit are reprocessed. value to determine which of the predetermined thicknesses the object corresponds to;
The buried object detection method according to claim 14. The buried object is wood, and the object is a gypsum board,
A buried object detection method according to any one of claims 9 to 15.

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