JPH0850180A - Electromagnetic induction type buried matter detecting device - Google Patents

Abstract

PURPOSE:To simultaneously measure the coordinate of the position of a buried pipe while measuring its position by providing an encoder for measuring the distance moved in the scanning direction when a scanning is carried out in the direction orthogonal to the longitudinal direction of the buried pipe. CONSTITUTION:An induction magnetic field is directly or indirectly added to a buried pipe 8. in a receiving sensor 1, a plurality of receiving coils are arranged so as to cross the induction magnetic field from the buried pipe 8 every fixed interval. A receiving amplifier 2 amplifies the induction magnetic field obtained by the receiving coils and converts it into current value. A receiving part 3 converts the current value from the amplifier 2 to voltage level. An encoder 4 measures the moving distance from a ground point X0 of a receiver body. An arithmetic display part 5 records the voltage level obtained by the receiving part 3 and the measured distance X as a pair of data, calculates the position of the buried pipe 8 from the track of the receiving level to a scanning distance, and calculates also the buried depth. The calculation results are two-dimensionally or tree-dimensionally displayed on a display part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting an underground buried object with high accuracy by using an electromagnetic induction technique, and particularly for detecting the position and depth of a buried pipe such as underground water, gas, electric power and telephone. The present invention relates to an electromagnetic induction type buried object detecting device.

[0002]

2. Description of the Related Art Conventionally, an apparatus for detecting an underground buried pipe by utilizing electromagnetic induction has been proposed based on the principle described below. That is, while indirectly or directly applying an induced magnetic field or an alternating current to the underground buried pipeline,
By scanning the receiving coil on the extension line of the pipeline so as to intersect with the induced magnetic field induced by the pipeline, the position where the induced voltage induced in the receiving coil is maximum is detected (maximum method). There is a method of measuring the position of. In addition, by scanning the receiving coil on the extension line of the pipeline so as not to intersect with the induced magnetic field induced from the pipeline, and detecting the position where the induced voltage induced in the receiving coil is minimum (minimum method). There is also a method of measuring the position of the pipeline.

Regarding the measurement of the depth of the buried pipe, 2
The two receiving coils are arranged at regular intervals in the vertical direction, and the induction electromagnetic field diffused in a cylindrical shape from the buried pipeline is obtained by the two receiving coils having an intensity that is proportional to the distance from the pipeline. As a principle, there is a method of measuring the depth from the intensity of each received electromagnetic field of two receiving coils. As an example of such an embedded object detection device, by improving the arrangement of the receiving coil or the method of calculating the received electromagnetic field, the accuracy of detecting the embedded object can be improved and the position of the embedded object can be on either the left or right side of the user. A device has been proposed that indicates whether there is a conductor and displays the proximity to a conductor such as a buried pipe (Japanese Patent Laid-Open No. 2-2800).
No. 80).

[0004]

However, although the conventional device can measure the position and depth of one buried pipe, in order to measure the laying route of the buried pipe, the buried pipe should be measured at a predetermined interval. After location measurements were made to identify routes, each location had to be surveyed and the coordinates of that location recorded. Therefore, there has been a demand for the development of a device that can measure the position of the buried pipe and simultaneously measure the coordinates of the position.

Therefore, an object of the present invention is to make it possible to measure the position of a buried pipe and simultaneously measure the coordinates of the position.

[0006]

In order to solve such a problem, the present invention performs measurement while scanning an AC electromagnetic field induced in an underground buried object, and from the change of the measured AC electromagnetic field. In an electromagnetic induction type embedded object detection device that detects the position of an embedded object, an encoder that measures the distance moved in the scanning direction when scanning in the direction intersecting the longitudinal direction of the embedded object, and a predetermined distance movement in the scanning direction The calculation display unit that acquires the strength of the alternating electromagnetic field and the moving distance each time and displays the moving distance at which the strength of the alternating electromagnetic field is maximum as the position of the buried object.

Further, when the scanning direction is the X-axis direction, a means for inputting a moving distance in the Y-axis direction orthogonal to the X-axis direction is provided, and the calculation display section has the maximum intensity of the AC electromagnetic field X. The moving distance in the axial direction is used as the position of the buried object, and at the same time, pipe line coordinate data consisting of at least the moving distance in the X-axis direction and the moving distance in the Y-axis direction is created, and based on the pipe line coordinate data, the buried object is set. The position is displayed. Further, the calculation display unit obtains the burial depth from the AC electromagnetic field, and at least obtains pipeline coordinate data from the moving distance in the X-axis direction at which the electromagnetic field strength is maximum, the input moving distance in the Y-axis direction, and the burial depth. It is created and the position of the buried object is displayed based on the pipeline coordinate data.

[0008]

When scanning in the direction intersecting the longitudinal direction of the buried object, the distance moved in the scanning direction is measured by the encoder, and the strength of the alternating electromagnetic field and the moving distance are measured each time the embedded object is moved a predetermined distance. Is acquired and displayed as the position of the buried object with the moving distance that maximizes the strength of the alternating electromagnetic field. As a result, while measuring the position of the buried pipe, the coordinates of the position can be simultaneously measured based on the moving distance output from the encoder. Further, when the scanning direction is the X-axis direction, pipe line coordinate data including the moving distance in the X-axis direction and the input moving distance in the Y-axis direction is created and the position of the buried object is displayed. Furthermore, the buried depth is obtained from the AC electromagnetic field, and the moving distance in the X-axis direction where the AC electromagnetic field strength is maximum,
Pipeline coordinate data is created from the input movement distance in the Y-axis direction and the buried depth, and the position of the buried object is displayed. Therefore,
The reception level of the induction electromagnetic field and the measurement position can be measured and recorded in a one-to-one correspondence, and the measurement results can be displayed in two or three dimensions, so that the installation route of the buried pipe is two-dimensional or three-dimensional. Is displayed on the screen and the installation status can be easily identified.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an electromagnetic induction type buried object detecting apparatus according to the present invention. In the figure, 1 is a receiving sensor, 2 is a receiving amplifier, 3 is a receiving unit,
4 is an encoder unit, 5 is a calculation display unit, 6 is a marker, 8 is a buried pipe, and 9 is the ground. Here, it is assumed that an induced magnetic field is directly or indirectly applied to the buried pipe 8,
Therefore, the oscillator for applying the induced magnetic field is omitted in FIG. In addition, the buried pipe 8 is assumed to exist immediately below the point P on the ground 9, and the receiver body such as the receiver amplifier 2 crosses the cross section of the buried pipe 8 from the starting point X0 to the measurement distance X.
Scanned in.

Next, the function of each part of the buried object detecting apparatus will be described. In the reception sensor 1, two or more reception coils are arranged so as to intersect the induction magnetic field from the embedded pipe 8 at regular intervals (H in the height direction H). The reception amplifier 2 amplifies the induced magnetic field obtained by the reception coil and converts it into a current value. That is, when measuring the depth of the buried pipe 8,
The induced currents corresponding to the induced magnetic fields obtained by the two receiving coils are amplified to obtain the respective induced current values. The receiving unit 3 automatically adjusts the gain and converts it into the voltage level E by comparing the current value obtained from the receiving amplifier 2 with the surrounding induction magnetic field level.

The encoder unit 4 measures the moving distance of the receiver body from the point X0. The calculation display unit 5 records the voltage level E and the measurement distance X obtained by the reception unit 3 as a pair of data, and calculates the position of the buried pipe 8 from the locus of the reception level with respect to the scanning distance, and also calculates the buried depth. be able to. Then, based on this calculation result, it is two-dimensional or three-dimensional.
It is displayed on a display unit (not shown) dimensionally. For example, there are a method of storing the loci of reception levels on each scanning section and displaying the data by superimposing them, and a method of displaying the calculated embedding position and embedding depth on a two-dimensional or three-dimensional diagram.

Next, with reference to FIG. 2, a detailed configuration of each part of the above-mentioned buried object detection apparatus will be described. The reception sensor 1 is composed of reception coils 11 and 12, and the coils are arranged at regular intervals H in the vertical direction. Each receiving coil 11, 12 has
They are arranged so as to be oriented in the scanning direction, and they are mounted so that their induced magnetic fields intersect at maximum when they cross the cross section of the buried pipe 8. The housing of the reception sensor 1 is made of synthetic resin such as vinyl chloride or polyethylene that does not block the electromagnetic field.

The reception amplifier 2 is connected to the reception coils 11 and 12 by filters / amplifiers 21 and 22, respectively, and the reception signals centered on the transmission frequency are generated by the filters / amplifiers 21 and 22 having a band pass filter function. Are band pass filtered and amplified. And the buried pipe 8
The comparator 23 calculates the ratio of the reception levels obtained through the filters / amplifiers 21 and 22 or the average value thereof when measuring the depth. In the position measurement, the reception level of either one of the filters / amplifiers 21 and 22 or the average value of both is used.

The receiving section 3 includes a mode switch 31, a receiving controller 32, a battery 33, and an A / D converter 3.
It consists of 4. The mode switch 31 switches the measurement mode of the position and depth of the buried pipe 8. Also in the position measurement, the operation of the comparator 23 can be controlled by selecting the maximum method and the minimum method described above. The reception controller 32 controls the reception level and the distance signal obtained from the encoder unit 4 to calibrate the maximum reception level and the distance from the starting point to form measurement data. The battery 33 supplies power to each part of the device. The A / D converter 34 A / D converts the reception level and the scanning distance and transfers the A / D conversion to the calculation display unit 5. The encoder unit 4 includes a scanning wheel 41 and an encoder 42. The scanning wheel 41 is composed of a pair or more wheels, and the number of rotations of the scanning wheel 41 is counted by the encoder 42 and transferred to the reception controller 32.

The calculation display section 5 includes a display circuit 51, a conduit position / depth calculation circuit 52, a data memory 53, and a floppy 54.
And a display 55. The display circuit 51 performs preprocessing for reproducing the data of the reception level and the scanning distance obtained from the reception controller 32 and graphically displaying the data on the display 55. The pipeline position / depth calculation circuit 52 calculates the pipeline position or the pipeline depth based on the maximum value or the minimum value of the reception level E with respect to the distance X. The calculation result and the data E and X are stored in the data memory 53 and displayed on the display 55. The data memory 53
The data stored in can be transferred and stored through a medium such as the floppy 54. Further, the detection result can be output to the printer 56. In addition, the marker 6 is
It is connected to the reception controller 32, and the measurement starting point X
0, the position of the buried pipe 8 is marked on the ground 9.

Next, FIG. 3 is a flow chart showing the operation and calculation algorithm of this buried object detecting apparatus, and the operation of the first embodiment of the present apparatus will be described based on this flow chart. Here, the frequency of the induction magnetic field used in this device is generally in the range of 1 kHz to 100, which is the range applied to underground pipes.
It is performed by selecting a specific frequency between kHz. In this device, it is possible to select a plurality of frequencies within these ranges by changing the transmission frequency of the oscillator (not shown) and by changing the filter characteristics of the reception amplifiers 21 and 22.

First, power is supplied to each part of the apparatus to set the operating frequency f. In this case, the operating frequency is set low when the buried pipe 8 is buried deep underground or when the diameter of the buried pipe 8 is large. Further, when the buried pipe 8 is buried in the ground shallowly or when the diameter of the buried pipe 8 is small, the operating frequency is set high. Then, the scanning start point X0 is set by the marker 6 (measurement switch) (step S1). Next, the operation of the mode switch 31 for setting each measurement mode of position or depth is detected, and the selection of the measurement mode is determined (step S2).

If the position measurement mode is selected, the reception level E and the scanning position (distance) X of the induced magnetic field obtained by the scanning of the reception sensor 1 are measured (step S3). Then, in the display circuit 51, these data E and X are two-dimensionally displayed on the display 55 (step S4). These series of measurements are performed by shifting the scanning start point by a predetermined distance in the direction orthogonal to the scanning direction, and the measurement data is stored in the data memory 53. In addition, when measuring only one place of the buried pipe 8, it is sufficient to scan a plurality of times from the same scanning start point. By expressing such data two-dimensionally as shown in FIG. 4 with the scanning origin as the origin of the coordinate axis, the change in the reception level can be displayed. Position P of pipeline
Since the point corresponds to the position where the reception level becomes maximum, the position of the buried pipe 8 can be determined from this two-dimensional display shown in FIG. By displaying this data for each scanning section as shown in FIG. 5 (step S5) and connecting the points P with straight lines, the buried line of the buried pipe 8 can be estimated (step S6).

Next, when the depth measuring mode of the buried pipe 8 is selected, the receiving levels E1 and E2 of the induced magnetic fields obtained from the two receiving coils 11 and 12 are measured and calculated through the comparator 23. The depth data D of the buried pipe 8 is calculated.
When the buried pipe 8 does not exist or the depth cannot be measured, “∞” indicating that measurement is impossible is displayed as the depth data D. When the depth of the buried pipe 8 is measured, the depth data D and the scanning position X are calculated (step S7). These measurements are performed while shifting the scanning starting point or a plurality of lines are performed on the same scanning section to measure the scanning data of multiple sections, and the data memory 53 is used.
(Step S8). The thus measured data is two-dimensionally or three-dimensionally displayed as described above to estimate the burial depth of the burial pipe 8 and the burial depth line (laying line) (step S9).

FIG. 4 is a diagram showing an example of the above-mentioned two-dimensional display result in the case of position measurement. In FIG. 4, the horizontal axis represents the scanning position X and the vertical axis represents the reception level E. here,
The position of the buried pipe 8 is a position where the reception level becomes maximum.
That is, the peak of reception level (point P) is dE / dX =
This is a point where 0 and d ² E / d ² X <0 are satisfied. In addition,
In this embodiment, an oscillator is directly connected to a pipe having a large diameter to generate an induced magnetic field, and the oscillator has an oscillation frequency of 33.
It is set to kHz. This large pipe is a steel pipe having a diameter of 80 mmφ, and the thin pipe is a metal pipe having a diameter of 30 mmφ.

Next, FIG. 5A is a diagram showing an example of the above-mentioned three-dimensional display result in the case of position measurement. In FIG.
The horizontal axis shows the scanning position X, and the scanning starting point X0 is represented as 0 point. The vertical axis represents the reception level E. In this way, by connecting the above-mentioned peaks of reception level (point P) represented on the scanning line, the position where the pipe is buried can be displayed in a line. Since such a display is difficult to display three-dimensionally, it is effective to use a display method in which a change in the reception level is replaced with a change in color. That is, FIG. 5 (b)
As shown in, the change in the reception level is expressed by the color change from the dark colors of blue, yellow, and white, and the peak of the reception level is displayed in a specific color (for example, red). It can be displayed in two dimensions, and the pipeline position can also be displayed. In this case, the pipeline position is obtained and specified from the peak of the reception level.

It should be noted that the positions of the buried pipes are obtained from a plurality of scanning lines, and the plurality of buried positions at which the reception level becomes maximum are shown in FIG.
When displaying a buried line by connecting with a straight line like
When the peak cannot be obtained in the middle of the embedding line, the embedding line is displayed by interpolating by connecting the peaks of the adjacent scanning lines. In this way, the position measurement of the buried pipe can be realized easily and accurately.

FIG. 6 is a block diagram showing another embodiment of the present invention, in which a wireless data transceiver 7 is added to the device shown in FIG. In the wireless data transmitter / receiver 7, the scanning distance X and the received level E of the induced magnetic field obtained by the receiver 3 are placed on a wireless carrier wave by the data transmitter and sent to a data receiver at a remote place. In the data receiver which receives this, this data is transferred to the arithmetic display unit 5 and processed.

Next, FIG. 7 is a block diagram showing the detailed structure of the apparatus of the other embodiment. The configuration of the device of this embodiment is
Each component of the wireless data transceiver 7 described above is added to the components of the device shown in FIG. That is, in FIG. 7, a data transmission circuit 71, a data reception circuit 72, and an antenna 73 are added. Here, the data transmission circuit 7
1 is placed on a carrier frequency of a predetermined radio frequency band and transmits a data signal by AM or FM modulation via an antenna 73, and this data signal is received by a data receiving circuit 72 via the antenna 73. After being reproduced, it is transferred to the display circuit 51. The operation and function of the calculation display unit 5 when the wireless data transmitter / receiver 7 is added are the same as those in the above case, and thus the description thereof is omitted.

As described above, in this embodiment, the reception level of the induction electromagnetic field and the measurement position have a one-to-one correspondence. Therefore, the present apparatus acquires the information on the embedding position and the embedding depth only by scanning. be able to. In addition, the two-dimensional or three-dimensional display can facilitate the recognition of the laying line of the buried pipe 8. Furthermore, since the device is simple, it can be economically performed for detecting work or investigating buried objects. Therefore, the accuracy of the detection technology, the improvement of workability, and the effect of economicization can be expected.

Next, FIG. 8 is a flow chart showing the operation of the second embodiment of the present invention, which shows the processing operation of the calculation display section 5 in detail. Further, FIG. 9 is a diagram showing the levels of electromagnetic waves received when one certain line is scanned. In the above-mentioned FIGS. 4 and 5, the reception level is two-dimensional or three-dimensional.
In contrast to the two-dimensional display, the position of the buried pipe 8 is obtained from the reception level and the position can be displayed two-dimensionally or three-dimensionally in the following second embodiment. First, a measurement reference point is set prior to measurement. Since the pipeline is usually laid parallel to the longitudinal direction of the road, the scanning direction is measured so as to cross the pipeline from the measurement reference point so as to cross the road. Here, the direction traversing the road is called the X-axis direction, the longitudinal direction of the road is called the Y-axis direction, and the depth direction is called the Z-axis direction. And the measurement is after scanning in this X-axis direction,
The measurement is performed by moving in the Y-axis direction by a predetermined distance (for example, 1 m) and scanning again in the X-axis direction.

First, a scan start switch (not shown) is pressed to scan from the measurement reference point in the X-axis direction. At this time, the scanning distance X is obtained by counting the number of rotations of the scanning wheel 41 by the encoder 42 (step S12), and it is determined whether or not the scanning distance X has reached a predetermined scanning interval Xd (step S1).
3). Here, the reception level is acquired when X = n × Xd (n is an integer) (step S14). Here, since the two receiving coils 11 and 12 receive, for example, at the scanning distance X11 shown in FIG. 9, the receiving levels Emn1 and Emn2 acquired in step 14 of FIG.
111 and E112, and the average value is obtained to obtain the reception level E11. In addition, m and n of Emn1 and Emn2
Indicates a measurement point, m is a position in the scanning section (Y-axis direction in FIG. 5), and n is a position in scanning distance (X-axis direction in FIG. 5).

Next, it is judged whether or not the differential value of the receiving level E112 of the receiving coil 12 located on the lower side is "0" (step S15), and if it is "0", the secondary differential value is further. Is determined to determine whether the reception level is maximum (step S16). If it is determined to be the maximum, the scanning distance X at this position is acquired (step S17). In the example of FIG. 9, the scanning distance at this time is X13. Next, the reception level E1
Calculate the burial depth from 11 and E112 (step S
18), scanning distance X, line Y coordinate and burial depth D11
Is written in the data memory 53 as pipeline coordinate data (step S19).

FIG. 10 shows an example of writing conduit coordinate data. It should be noted that the Y coordinate data is obtained in step S described later in FIG.
The value input at 21 is written, or if the Y coordinate is set to a constant interval, control is performed so that the Y coordinate value is added for each measurement of one line, and the Y coordinate value at this time is written. To do. Then, returning to the flowchart of FIG. 8 again, after writing the pipeline coordinate data in step S19, the process returns to step S11 to determine whether or not the measurement of one line is completed. For example, it is determined that one line has ended by detecting the pressing of a scan end switch (not shown). And 1
When the line measurement is completed, the input of Y coordinate data indicating the line to be measured next is waited for (step S20). If the Y coordinate data is input, the value of this Y coordinate is acquired and written in the data memory 53 ( Step S21), Step S
Return to 11.

When the measurement of one line is completed and the measurement end switch (not shown) is pressed instead of inputting the next Y coordinate in step S21, it is judged that all the measurements are completed and the measurement is completed. To do. Next, FIG. 11 shows the calculation display unit 5 based on the pipeline coordinate data created by the above measurement.
It is a figure which shows the example displayed two-dimensionally. Of these, FIG.
FIG. 11A is an example in which the pipeline position is two-dimensionally displayed.
(B) is an example in which the buried depth is two-dimensionally displayed along with the Y axis.

FIG. 12 is a diagram showing an example of three-dimensional display on the calculation display unit 5 based on the pipeline coordinate data. In this way, in this device, the scanning distance and the position of the buried pipe 8 are set to one to one.
Since the data can be recorded in correspondence with the above, the data can be displayed in a two-dimensional or three-dimensional manner on the display unit so that the installation route of the buried pipe 8 can be easily recognized and the recorded data can be copied to a recording medium and carried. It is also possible to automatically plot the installation route on the drawing using.

[0032]

As described above, according to the present invention, when a buried object is scanned, the buried object is scanned in a direction intersecting the longitudinal direction, and the distance moved in the scanning direction is measured by an encoder. The strength and the moving distance of the alternating electromagnetic field are acquired each time the moving object moves in the scanning direction, and the moving distance that maximizes the strength of the alternating electromagnetic field is displayed as the position of the buried object. While measuring the position, the coordinates of the position can be simultaneously measured based on the moving distance output from the encoder. Further, when the scanning direction is the X-axis direction, pipe line coordinate data composed of the moving distance in the X-axis direction and the input moving distance in the Y-axis direction is created and the position of the buried object is displayed. Therefore, the laying route of the buried pipe is displayed two-dimensionally, and the laying condition can be easily recognized. Furthermore, the buried depth is obtained from the AC electromagnetic field, and pipeline coordinate data is created from the moving distance in the X axis direction where the AC electromagnetic field strength is maximum, the input moving distance in the Y axis direction, and the buried depth, and Since the position is displayed, the laying route of the buried pipe is displayed three-dimensionally, and the laying condition can be identified at a glance.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing an embodiment of an electromagnetic induction type buried object detection apparatus according to the present invention.

FIG. 2 is a detailed block diagram of the device.

FIG. 3 is a flowchart showing the operation of the above apparatus.

[Fig. 4] When detecting an embedded object in the above device,
It is a figure which shows the relationship in two dimensions of the obtained receiving level and scanning movement distance.

[Fig. 5] When detecting a buried object in the above device,
It is a figure which shows the three-dimensional relationship between the obtained reception level and each moving distance of an X-axis direction and a Y-axis direction.

FIG. 6 is a schematic block diagram of an apparatus according to another embodiment.

FIG. 7 is a detailed block diagram of an apparatus according to another embodiment.

FIG. 8 is a flowchart showing the operation of the second embodiment of the buried object detection apparatus.

FIG. 9 is a diagram showing a reception level of an induction electromagnetic field obtained when one line is scanned in the above device.

FIG. 10 is a chart showing a storage state of created pipeline coordinate data in a memory.

FIG. 11 is a diagram showing an example of two-dimensional display based on created pipeline coordinate data.

FIG. 12 is a diagram showing an example in which three-dimensional display is performed based on created pipeline coordinate data.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Receiving sensor, 2 ... Receiving amplifier, 3 ... Receiving part, 4 ... Encoder part, 5 ... Computation display part, 7 ... Wireless data transmitter / receiver, 8 ... Buried pipe, 9 ... Ground, 11, 12 ... Receiving coil, 21, 22 ... Filter / Amplifier, 23 ... Comparator,
31 ... Mode switch, 32 ... Reception controller, 3
4 ... A / D converter, 42 ... Encoder, 51 ... Display circuit, 52 ... Pipeline position / depth calculation circuit, 53 ... Data memory, 55 ... Display device.

Claims (3)

[Claims] 1. An electromagnetic induction type buried object detecting apparatus for performing a measurement while scanning an alternating current electromagnetic field induced in an underground buried object and detecting the position of the buried object from a change in the measured alternating current electromagnetic field, An encoder that measures the distance moved in the scanning direction when scanning in a direction intersecting the longitudinal direction of the embedded object,
A calculation display unit that acquires the strength and the moving distance of the alternating electromagnetic field each time the moving object moves a predetermined distance in the scanning direction, and displays the position as the position of the buried object with the moving distance that maximizes the strength of the alternating electromagnetic field. An electromagnetic induction type embedded object detection device characterized by comprising: 2. The electromagnetic induction type buried object detecting apparatus according to claim 1, further comprising means for inputting a moving distance in a Y-axis direction orthogonal to the X-axis direction when the scanning direction is the X-axis direction. The calculation and display unit determines the position of the buried object with a moving distance in the X-axis direction that maximizes the strength of the AC electromagnetic field, and at least from the moving distance in the X-axis direction and the moving distance in the Y-axis direction. An electromagnetic induction type embedded object detection device, characterized in that it creates pipeline coordinate data and displays the position of the embedded object based on the pipeline coordinate data. 3. The electromagnetic induction type buried object detection device according to claim 2, wherein the calculation display unit obtains a buried depth from the AC electromagnetic field, and at least a moving distance in the X-axis direction where the electromagnetic field strength is maximum. An electromagnetic induction type embedded object detection device, characterized in that pipeline coordinate data is created from the input movement distance in the Y-axis direction and the buried depth, and the position of the buried object is displayed based on the pipeline coordinate data. .