JP3872579B2 - Underwater exploration equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for exploring a water bottom from an echo of an ultrasonic wave radiated toward the water bottom.
[0002]
[Prior art]
The present applicant has previously proposed an underwater detection device that detects a wide range of areas with the "Underwater Detection Device" (Japanese Patent Application No. 5-210646) and displays it as a plane image. A brief introduction.
As shown in FIG. 1, an array-type transducer 1 (detailed later) mounted on the bottom of the ship forms a transmission beam Dv that spreads in a fan shape toward the seabed, and then receives a directional sharp reception beam R. , For example, the depth of the bottom of the water is detected for the band-like region S ₁ (actually, the beam spreads laterally, so that the width is widened as shown in FIG. 2). Next, after turning the transmitter / receiver 1 at a predetermined step angle, the operation of the transmitter / receiver is repeated to detect the depth of the water bottom in the region S ₂ shown in FIG. When the transducer is turned 180 °, a three-dimensional region having its own ship Q as the apex and the circular exploration region S ₀ as the bottom is detected, and based on the detection result, as shown in FIG. Then, the depth diagram of the bottom Z is completed by the PPI image as when viewing the wide bottom from the ship on the display CRT.
[0003]
As shown in FIG. 4, if the received beam from the transmitter / receiver is scanned from one direction to the other side, it is necessary to turn the transmitter / receiver 360 °.
[0004]
Here, the bottom of the water is caught by simply detecting the maximum echo, but if a means for discriminating data between the underwater object and the bottom of the water is provided, only the underwater object G is displayed as shown in FIG. As shown in FIG. 6, the bottom Z can be displayed on the background portion outside the display area of the underwater object G.
[0005]
The water bottom Z in FIG. 3 and the underwater object G in FIG. 5 can be displayed for each color according to the level of the signal or depth information included in the signal, or can be displayed in shades of a single color. H shown at the lower right of the display CRT in FIGS. 3 and 5 is a color bar indicating the depth or echo level.
[0006]
In addition, as shown in FIG. 6, if the underwater object G and the bottom Z are displayed simultaneously, the underwater object is displayed by color according to the signal level, and the underwater is separately displayed according to the depth information included in the signal. When the color is displayed in shades, the display is easy to see.
[0007]
Furthermore, if the vertical cross-sectional image F in the direction passing through the underwater object G is displayed together with the display E on the display CRT as shown in FIG. 6, the depth relationship between the water bottom Z and the underwater object G can be easily grasped. be able to.
[0008]
According to this device, it is possible to observe the undulation state of the seabed over a wide range from the water depth information.
[0009]
[Problems to be solved by the invention]
By the way, small fish have a habit of gathering on protrusions on the seabed, and small fishing boats and pleasure boats are trying to catch high-class fish and large fish that gather to eat small fish. Projections include fish reefs, artificial reefs, shipwrecks, etc. If such protrusions can be detected by the above-described underwater detection device, fishery efficiency will be improved.
[0010]
As shown in the cross-sectional view of FIG. 7, the case where there is a protrusion U ₁ that is relatively higher than the seabed depth is shown. In this case, the protrusion U ₁ is clearly displayed in the plane drawing based on the PPI drawing. ing. On the other hand, FIG. 8 shows a case where the height of the protrusion U ₁ is lower than the depth of the seabed. In this case, since the degree of change in the depth of the protrusion U ₁ is slight, no protrusion is displayed in the display image. . In addition, when the hull is shaken, an error occurs in the detected depth, but the error increases as the surveyed location moves away from the ship. As a result, a virtual image may appear as if there are protrusions on the flat seabed.
[0011]
Accordingly, an object of the present invention is to provide a water bottom exploration device that can clearly detect a protrusion even when the height of the protrusion is lower than the depth, and can reduce detection errors caused by the movement of the hull.
[0012]
[Means for Solving the Problems]
In FIG. 9, as an example, as shown in FIG. 9 (a), seabed data in the case where half of the shipwreck U ₁ is buried in the sea floor several hundred meters below the sea surface is taken as an example. The numerical values of 0 and 255 at the left end are obtained by dividing the depth into 256. If only depth information is taken from the seafloor data, the depth is slightly raised as U ₂ at the location of the shipwreck U ₁ as shown in FIG. With such ratio of the height of the sunken U1 for depth of the seabed is small, U ₂ is not displayed even if it is displayed the depth data as described above. (c) The figure shows the level of the received signal. When the above-mentioned projection is a shipwreck U ₁ or a fish reef, the signal level is not limited even if the height of the projection is smaller than the depth of the seabed. If caught, there is a large difference in reflection intensity between the sandy seabed and such protrusions, so that it appears large as indicated by U ₃ . Therefore, when the amount of change with respect to the reference value (depth average value) in (b) is extracted and the amount of change is superimposed on (c), the shipwreck U ₁ is U ₄ as shown in (d). If the PPI is drawn based on this data, the shipwreck U ₁ is clearly displayed as U ₅ as shown in FIG.
[0013]
As shown in FIG. 9, the depth and level are both shown in 256 stages of 0 to 255, and when these different types of signals are superimposed, simple addition may be used, or the amount of change is multiplied by a correction coefficient. The values may be superimposed.
[0014]
In FIG. 9, since the level change U ₃ with respect to the protrusion U ₁ is significantly detected by the level signal, it is not meaningful to superimpose the depth change amount U ₂ , but this depth change amount is superimposed. The reason for this is as follows. An embodiment in which only the level change is displayed will be described later.
[0015]
In FIG. 9, the incident angle of the shipwreck U ₁ as viewed from own ship Q (the angle formed directly below) is large. However, as shown in FIG. 10, when shipwreck U ₁ is directly under ship Q. (C) As shown by U ₃ in the figure, the signal level from the seabed and the wreck becomes smaller, and there may be almost no difference depending on the bottom sediment. Even in such a case, if superimposes the depth variation U ₂ of the signal level (b) view, as in U ₄ of (d) diagrams, in order to level variation U ₄ is emphasized (e) Displayed on the display as shown.
[0016]
9 and 10, the display base is a signal level. FIG. 11 is a diagram in which a change amount with respect to a reference value (level average) of the level is detected and the level change amount is superimposed on the depth. Is the depth.
[0017]
As described above, when the hull is shaken, the error of the depth data is greatly enlarged as the distance from the own ship increases, and a virtual image is generated. Since the present invention displays based on the total value of (depth element + level element), if the weight of the depth is reduced as the distance from the ship increases and the signal level is compensated accordingly, Errors can be suppressed. For this reason, a weight is set for the depth data so that the value decreases as the distance from the ship becomes lower.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 12 is a control block diagram showing an embodiment of the water bottom exploration device of the present invention. Reference numeral 1 denotes a transmitter / receiver for transmitting and receiving ultrasonic waves. FIG. 13 shows a transmitting / receiving wave 1 and a turning mechanism unit 2 comprising a motor M and a reduction gear G for turning the received wave 1 in a stepped manner. ing. As shown in the plan view of FIG. 14, the transducer 1 has a square shape, and a plurality of transducers 1A are arranged in an array.
[0019]
At the time of transmission, by simultaneously exciting several vibrators 1A in the center of the transmitter / receiver 1, a transmission beam U spreading in a cone shape as shown in FIG. 1 is obtained, and when the echo is received In other words, by giving a constant delay amount or phase shift amount between adjacent transducers to the received signal of each transducer 1A, the received signals of each transducer 1A with respect to the echo signal from a specific direction. As a result of the signal phases being aligned, a received beam R is formed in the specific direction. Therefore, by continuously changing the delay amount, the received beam R scans the band-like region S ₁ that passes through the direction immediately below the transducer 1 and extends in the transducer arrangement direction of the transducer ₁ . Is done.
[0020]
2a is a transducer drive unit for driving the motor M. Reference numeral 3 denotes a transmission unit that supplies a drive signal for ultrasonic transmission to each transducer 1A of the transducer 1 and supplies a drive signal capable of obtaining a wide range of directivity. A receiver 4 amplifies and detects the signal received by the transducer 1 and gives a predetermined delay amount to each detected signal from each transducer 1A in order to scan the received beam as described above. Part. A transmission / reception system control unit 5 controls the transmission unit 3 and controls the above-described reception unit.
[0021]
Reference numeral 6 denotes an A / D converter that converts the received signal obtained from the receiving unit 4 from analog to digital, and the converted digital signal is stored in the buffer memory 7. Reference numeral 8 denotes a coordinate conversion unit for converting the polar coordinate system data D (r, θ) into the Cartesian coordinate system data D (X, Y). 9 and the vertical section video memory 9a. These A / D conversion unit 6, buffer memory 7 and coordinate conversion unit 8 operate in synchronization with the clock from the transmission / reception wave system control unit 5.
[0022]
Reference numeral 10 denotes a sampling circuit. When data for one vertical section is stored in the vertical section image memory 9, the data is read out from the vertical section memory 9 one line at a time in the depth direction. Address (seafloor depth) when the peak value is detected or its peak value, address when the peak value is detected from the data excluding the peak value (depth of underwater object), and the previous peak value (from the seabed) Echo level). 11A is a seabed data memory for storing the echo level and seabed depth by the sampling circuit 10, and 11B is an underwater data memory for storing the echo level and depth data of the underwater object.
[0023]
Reference numeral 12 denotes a display system control unit. Based on various display data set and input from the operation unit 13, setting data such as a turning range and a depth is sent to the sampling circuit 10 for the transmission / reception system control unit 5. In addition, a sampling range (depth) is supplied, and further, a memory 12a for storing data from the seabed data memory 11A and data from the underwater data memory 11B, seabed data (level, depth), and underwater data (level) , Depth) display color tone table 12b, image data created with reference to the color tone table 12b is supplied to the PPI image drawing unit 14, and the character / symbol drawing unit 15 is described later. A signal for characters and symbols displayed on the display 19 is sent out. The creation of image data according to the present invention will be described in detail later. Reference numeral 16 denotes a PPI image video memory for storing display data of a PPI image created by the PPI drawing unit 14, and reference numeral 17 denotes a character / symbol for storing character and symbol image data created by the character / symbol drawing unit. Video memory.
[0024]
A video signal conversion unit 18 converts video data from the video memories 9a, 16 and 17 into color data or grayscale data according to depth. A video clock unit 20 supplies a clock to each of the video memories 9a, 16, 17 and the video signal conversion unit 18.
[0025]
The operation of the apparatus having the above configuration will be described in detail with reference to the flowchart of FIG.
As an initial setting, information such as a depth range L ₁ to L ₂ (see FIG. 16) to be searched and a step turning angle of the transducer 1 is input by the operation unit 13 in step S1. As L ₂ , a value larger than the depth of the seabed Z which is roughly known as shown in FIG. 16 is adopted. In the next step 3, wave transmission is performed, and in step S4, the narrow-directed received beam R is scanned as shown in FIG. This scan 1 when the reception data D _V of the vertical cross-section fractions are stored, the process proceeds from step S5 to step S6, as shown in FIG. 17, one line from the memory 9 in accordance with the depth range L ₁ to L ₂ Minutes of data are read out. The data for one line corresponds to each received beam R. FIG. 16 shows a polar coordinate system, whereas FIG. 17 shows an orthogonal coordinate system.
[0026]
In step S7, the level peak value at that time and the depth (sea floor depth) at that time are detected, and in step S8, the level peak value and depth data are stored in the sea floor data memory 11A. In step S9, it is determined whether reading of all lines (one vertical section fraction) has been completed, and the loop of steps S6 to S8 is repeated until reading of all lines is completed.
[0027]
When the reading of all lines for one vertical cross-section is completed, the process proceeds from step S9 to step S10, and the seabed depth L ₀ (see FIG. 16) immediately below the ship Q is recognized from the data in the seabed data memory 11A. . In the next step S11, L ₂ = L ₀ −α = L ₂ ′ is adopted as the accurate depth L ₂ .
[0028]
In the next step S12, the lines are read again from the vertical section image memory 9 in the depth direction, but the depth range at that time is L ₁ to L ₂ (= L ₀ −α). Only the echo data is read out, the level peak value and the depth data are detected in step S13, and stored in the underwater data memory 11B in step S14. Then, the flow from step S12 to step S14 is executed until data is read for all lines.
[0029]
When data reading is completed for all lines in this way, the process proceeds from step S15 to step S16, and the display system control unit 12 superimposes the echo level on the depth data for one vertical sectional image. The processing in step S16 will be described in detail with reference to the subroutine of FIG.
[0030]
When seabed data seabed data memory 11A at step S21 is read into the display system control unit 12, based on the seabed depth L ₀ determined for the one vertical sectional image in the next step S22, the one vertical section A depth change amount ΔD in the image is calculated. In the next step S23, a weight is set for the amount of change ΔD as a countermeasure against ship sway. As the weight value, for example, a value in which the weight of “1” directly below own ship Q decreases linearly to “0.3” on both sides is adopted.
[0031]
In parallel with this, when level data is read from the level data memory 11C into the display system control unit 12, the process proceeds from step S24 to step S26, and the level data is corrected so as to be a constant level signal regardless of the depth. The data is subjected to horizontal TVG gain correction. In step S26, the depth change amount ΔD is superimposed on the level data. The superimposed data is sent to the PPI drawing unit 14.
[0032]
Returning to FIG. 15, in step S <b> 17, PPI drawing referring to the color tone table 12 b is performed based on the superimposition data for one vertical cross-sectional image. In step S <b> 18, it is determined whether the PPI drawing is completed. After returning from step S18 to step S2 and turning the transducer 1 by the step angle, the seabed is displayed on the display 19 as a PPI image by repeating the above-described operation.
[0033]
FIG. 19 shows a display example of this apparatus. The seabed is displayed as a base color with level data. A high protrusion is displayed as the level data superimposed with the amount of change in depth. Schools of fish are displayed based on their school data (depth or signal level). A low protrusion at a position away from the own ship position (with a large incident angle) is displayed mainly based on the level data because the amount of change in depth (the error is large due to the shaking of the hull) is suppressed by the weight function.
[0034]
When an underwater object such as a school of fish is displayed on the display, underwater data from the underwater data memory 11B is added to the superimposed data. At that time, for example, the school of fish and the bottom of the sea can be clearly distinguished from each other, for example, the school of fish is displayed by color according to its depth or echo level, and the sea bottom is white-gray-black density according to its depth. It is good to display with change.
[0035]
When the ship is shaken, the error in the depth data is increased as the exploration area is further away from directly under the ship. Therefore, by setting the weight function in the depth data as described above, the signal level in the area away from directly under the ship is attenuated and compensated by the signal level, thereby reducing the error associated with the hull motion as described above. it can.
[0036]
In this flow, after the data reading from the vertical section image memory 9 and the data processing are completed, the process proceeds to the next turning and transmission / reception of the transmitter / receiver 1. However, by actually having two memories, The transmission / reception and data processing are performed in parallel.
[0037]
In the embodiment described above (corresponding to FIGS. 9 and 10), the display base is a signal level. However, the second embodiment (corresponding to FIG. 11) of the present invention in which the display base is a depth is used. State.
Control in the display system control unit 12 in that case is shown in FIG. When the level data of one vertical section is fetched from the seafloor data memory 11A to the display system control unit 12 in step S31, the process proceeds from step S31 to step S32, and the horizontal TVG gain correction is performed on the level data. In S33, an average level is obtained from the level, and a level change amount ΔR is detected based on the average level. On the other hand, when the seafloor data in the seafloor data memory 11A is read by the display system control unit 12, the process proceeds from step S34 to step S35, and a weight is set for the change amount ΔD as a countermeasure for ship shaking. In step S 36, the level change amount ΔR is superimposed on the depth data, and the superimposed data is supplied to the PPI image drawing unit 14.
[0038]
In the above embodiment, two types of signals are superimposed, but FIG. 21 shows a third embodiment of the present invention, in which sea level data of level and depth is detected in step S41. In step S42, one depth data is read out from the seabed data, and in step S43, a change amount is detected from the depth data, and a weight is set for the change amount as a countermeasure for ship shaking. While PPI drawing is performed with a color tone corresponding to the change amount set for the weight, level data is read out from the seabed data in step S45, and in step S46, the above-described horizontal TVG is set, and based on the data. For example, PPI is drawn in monotone as a background. In this display example, the projection has a large height difference.
[0039]
FIG. 22 shows a fourth embodiment of the present invention. When level and depth seabed data is detected in step S51, one level data is read from the seabed data in step S52. In step S53, the horizontal TVG is set. In step S54, the amount of change is detected from the level data, and PPI drawing is performed with a color according to the amount of change. In step S55, depth data is read from the seabed data. In step S56, the above-described weight is set, and based on the data, PPI drawing is performed in, for example, monotone as the background. In this display example, there are protrusions with a small height difference, that is, artificial reefs and the like.
[0040]
【The invention's effect】
As described above, the echo level from the depth and bottom of the water is detected for a wide area, the amount of change with respect to the reference value of the depth is obtained, and the change is displayed based on the data obtained by superimposing the amount of change on the echo. Since the PPI is drawn on the vessel, the protrusion is clearly displayed regardless of the height and position of the protrusion on the bottom of the water. In this case, since the signal level is displayed as a display base like a fish finder that is already frequently used, it is easy to visually capture the display image.
Further, in the second embodiment of the present invention, the amount of change with respect to the reference value of the echo level is obtained, and PPI drawing is performed on the display based on the data obtained by superimposing the amount of change on the depth. It can be operated with the same feeling as the “detection device”.
Furthermore, in the present invention, the depth error due to the shaking of the hull is reduced simply by setting the weight to the detected depth, and there is no need for an expensive sensor and complicated control.
As in the third and fourth embodiments of the present invention, the same effect can be obtained even if the depth data or the PPI drawing is performed based on the change amount of the level data.
[Brief description of the drawings]
FIG. 1 is a diagram showing a transmission and reception beam in an underwater exploration device. FIG. 2 is a diagram showing an exploration area when the transducer used in FIG. 1 is swung. FIG. 3 is a seabed obtained by an underwater detection device. FIG. 4 is a diagram showing a modified example of the exploration method of FIG. 1. FIG. 5 is a diagram showing a display example of a school of fish obtained by an underwater detection device. Example of display in which one vertical sectional view is written in addition to PPI display [FIG. 7] Example of display when PPI is drawn based on water depth information shown in sectional view [FIG. 8] In FIG. Display example when the hull sways [Fig. 9] Corresponding diagram of claim 1 [Fig. 10] Fig. 9 shows another operation mode of Fig. 9 [Fig. 11] Corresponding diagram of claim 2 [Fig. FIG. 13 is a control block diagram showing an embodiment of the apparatus. FIG. 14 is a plan view of the transducer shown in FIG. 13. FIG. 15 is a flowchart showing the control operation of the apparatus shown in FIG. 12. FIG. 16 is one scan by the transducer shown in FIG. FIG. 17 is a diagram showing the state of underwater explored in FIG. 17. FIG. 18 is a diagram showing reading of data stored in the vertical sectional image memory of FIG. 16. FIG. 18 is a detailed diagram of the first embodiment for step S16 in FIG. FIG. 19 is a PPI drawing example obtained by the bottom survey apparatus of FIG. 12. FIG. 20 is a subroutine showing details of the second embodiment for step S16 of FIG. 15. FIG. FIG. 22 is a flowchart showing the control performed in the embodiment of the present invention. FIG. 22 is a flowchart showing the control performed in the fourth embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 Transmitter / receiver 2 Transmitter / receiver turning mechanism part 2a Transmitted / received wave driving part 3 Transmitting part 4 Receiving part 5 Transmission / reception system control part 6 A / D converter 7 Buffer memory 8 Coordinate converting part 9 Vertical sectional view memory 9a Vertical sectional view Video memory 10 Sampling circuit 11 A Submarine data memory 11 B Underwater data memory 12 Display system control unit 12 a Memory 12 b Color tone table 13 Scanning unit 14 PPI image drawing unit 15 Character / symbol drawing unit 16 PPI image video memory 17 Character / symbol image video memory 18 Video memory signal converter 19 Display 20 Video clock unit

Claims (6)

 Transmit and receive ultrasonic waves using a transducer, detect the depth of water in a wide range of areas around the transducer and the level of echoes from the bottom, determine the amount of change with respect to the reference value of the depth, and calculate the amount of change. A water bottom exploration device characterized in that it is displayed as a plane image on a display based on data obtained by superimposing the echo level signal.  The transmitter / receiver is used to transmit / receive ultrasonic waves, detect the echo level from the water depth and bottom of the wide area around the transmitter / receiver, determine the amount of change of the echo level relative to the reference value, and calculate the amount of change. A water bottom exploration device that displays a flat image on a display based on data obtained by superimposing the water depth data.  After transmitting ultrasonic waves toward the bottom of the water, use a transducer that scans a directional received beam and receives echo signals from a fan-shaped area below the ship. By repeating the transmission / reception operation every time the vehicle is turned at a predetermined step angle, the water depth and the echo level from the water bottom are detected from the echo signal in the water bottom exploration device that explores a wide area around the ship. A water bottom exploration apparatus characterized in that a change amount with respect to a reference value of the water depth is obtained, and the change amount is displayed as a plane image on a display based on data obtained by superimposing the change amount on the echo level. After transmitting the ultrasonic wave toward the bottom of the water, scan the received beam and receive the echo from the fan-shaped area below the ship, using the transmitter / receiver as a predetermined step. By repeating the operation of transmitting and receiving waves every time it turns at a corner, the water bottom exploration device that explores a wide area centering on its own ship detects the water depth and the level of echo from the water bottom from the echo signal, and the echo A water bottom exploration device characterized by obtaining a change amount with respect to a reference value of a level and displaying the change amount as a plane image on a display based on data obtained by superimposing the change amount on the water depth data.  The bottom survey according to any one of claims 1 to 4, wherein a weight is set for the depth data so that the numerical value decreases as the distance from the vessel is lower, in order to reduce errors in the depth data due to the motion of the hull. apparatus. The underwater exploration device according to any one of claims 1 to 5, wherein an echo level or depth from an underwater object is detected and the underwater object is displayed on the display.

Images