JPH11153667A - Water bottom searching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To clearly indicate even a low projection existing at sea bottom. SOLUTION: A water bottom searching device examining a wide region from self ship in the center by scanning a narrow directional reception beam after transmitting ultrasonic wave toward the water bottom, using an array type transmitter and receptor receiving echo from the region spreading below the self ship in fan shape and repeating the operation of the transmission and reception wave at every rotation of the transmitter receiver by specific step angle. In this case, by detecting the water depth and echo level from the water bottom using the echo signal, calculating the variation from the reference value of water depth, overlapping the variation on the echo, a plane image is indicated on a display based on the overlapped echo.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for exploring a water bottom from echoes of ultrasonic waves radiated toward the water bottom.

[0002]

2. Description of the Related Art The present applicant has previously proposed an underwater detection device that detects a wide area using an "underwater detection device" (Japanese Patent Application No. 5-210646) and displays it as a plane image. Here, the technical contents are briefly introduced. As shown in FIG. 1, a transmission beam Dv spreading in a fan shape toward the sea bottom is formed from an array type transducer 1 (described in detail later) mounted on the bottom of a ship, and then a reception beam R having a sharp directivity is formed. Is detected, for example, the depth of the water bottom is detected with respect to the band-shaped region S ₁ (actually, the beam spreads out on the side as shown in FIG. 2 so that the width is widened around the periphery). By then repeating the operation of the transmitting and receiving wave transducer 1 from turning by a predetermined step angle, detects the water bottom depth similar to the region S ₂ shown in FIG. When the transducer turns 180 °, own ship Q
Are all vertices, and a three-dimensional area having a circular search area S ₀ as a bottom face is detected throughout. Based on the detection results, FIG.
As shown in FIG. 7, a depth map of the water bottom Z based on the PPI image as when a wide range of the water bottom is viewed from the ship is completed on the display CRT.

[0003] As shown in FIG. 4, in order to scan a beam received by a transducer from just below to one side, it is necessary to turn the transducer 360 °.

Here, the bottom of the water is caught by simply detecting the maximum echo. However, if means for discriminating data between the underwater object and the water bottom is provided, as shown in FIG.
Only the water bottom Z can be displayed on the background portion outside the display area of the underwater object G as shown in FIG.

The underwater object Z in FIG. 3 and the underwater object G in FIG.
Depending on the level of the signal or the depth information included in the signal, it can be displayed for each color, or can be displayed in 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 the echo level.

If the underwater object G and the water bottom Z are simultaneously displayed as shown in FIG. 6, the underwater object is displayed in different colors according to its signal level, and the water bottom is included in the depth information included in the signal. Accordingly, if a different shade of color is displayed, the display becomes easy to see.

Further, if a vertical sectional view F in the direction passing through the underwater object G is displayed along with a 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 determined. Can be grasped.

[0008] According to this apparatus, the undulation of the seabed can be observed over a wide range from the water depth information.

[0009]

By the way, small fish tend to gather on protrusions on the seabed, and small fishing boats and pleasure boats try to catch high-grade fish and large fish that gather to eat small fish. Projections include fish reefs, artificial reefs, and wrecked ships. If such projections can be detected by the above-described underwater detection device, fishing efficiency will increase.

As shown in the sectional view of FIG. 7, there is shown a case where there is a protrusion U ₁ which is relatively higher than the depth of the seabed. In that case, in a plan image based on PPI drawing, the protrusion U _{1 is shown.}
Is clearly displayed. On the other hand, FIG. 8, as compared to the seabed depth indicates if a low height of the projections U _1, since such a case is only the degree of depth variation of protrusion U _1, projection display image is not displayed . Further, if the hull sways, an error occurs in the detected depth, but the error increases as the search location moves away from the ship. As a result, a virtual image may appear as if there is a protrusion on the flat seabed.

Accordingly, an object of the present invention is to provide a water bottom exploration apparatus capable of clearly detecting a projection even when the height of the projection is lower than the depth, and reducing a detection error caused by the sway of the hull. And

[0012]

9 SUMMARY OF THE INVENTION, taken as an example seabed data when not filled as projections as in (a) Figure, wreck U ₁ is half seabed below sea level several hundred m. The numerical values of 0 and 255 at the left end are obtained by dividing the depth into 256. Taking only the depth information from the seabed data, as (b) diagram, the depth at the location of the sunken U ₁ is raised slightly as the U _2. Thus the wreck U against the depth of the seabed
When the ratio of the first height is small, U ₂ is not displayed even if it is displayed the depth data as described above. (c) Figure is obtained by displaying the level of the received signal, if projections as described above is sunken U ₁ and reefs, the height of the protrusion is smaller than the seabed depth, the signal level grasped if, for at the sandy seabed with such projections that have large difference in reflection intensity appears largely as shown by U _3. Therefore, when the amount of change with respect to the reference value (depth average value) of the depth in the figure (b) is extracted and the amount of change is superimposed on the figure (c),
(d) Figure as described, appear larger as wrecks U ₁ is U _4, the if PPI drawing based on the data, the wreck U ₁ as (e) view is clearly displayed as a U _5.

[0013] As shown in FIG.
255 are shown in 256 stages, and when these different types of signals are superimposed, simple addition may be performed, or
A value obtained by multiplying the change amount by the correction coefficient may be superimposed.

In FIG. 9, since the level change U ₃ with respect to the protrusion U ₁ is remarkably detected in the level signal, it does not make much sense to superimpose the depth change U _2. The reason for the superposition is as follows.
An embodiment for displaying only the level change will be described later.

FIG. 9 shows a case where the angle of incidence of the wreck U ₁ viewed from the own ship Q (the angle between the ship and the ship directly below) is large.
As of, the incident angle becomes small when directly below the ship Q such that there is wreck U _1, as shown by U ₃ (c), Figure, the signal level from the seabed and wreck the difference becomes smaller In some cases, there is almost no difference depending on the sediment of the seabed. Even in such a case, the signal level is changed to the depth change amount U in FIG.
If superimposing _2, as in the U ₄ of (d) Figure, the level variation U
₄ is highlighted on the display as shown in FIG.

FIGS. 9 and 10 show a case where the signal level is used as the display base. FIG. 11 shows a case where the amount of change with respect to a reference value (level average) of the level is detected and the amount of change in the level is superimposed on the depth. , The display base is depth.

When the hull sways as described above, the error of the depth data is greatly enlarged as the distance from the ship increases, and a virtual image is generated. The present invention is based on (depth element +
(Level element) is displayed based on the total value, so as you move away from your ship, reduce the depth weight,
If the signal level is compensated for, the above-described error can be suppressed. For this purpose, a weight is set for the depth data such that the value decreases as the distance from the position directly below the ship increases.

[0018]

FIG. 12 is a control block diagram showing an embodiment of a water bottom exploration apparatus according to the present invention. Numeral 1 denotes a wave transmitter / receiver for transmitting and receiving ultrasonic waves. FIG. 13 shows a wave transmitting / receiving wave 1 and a turning mechanism 2 comprising a motor M and a reduction gear G for turning the wave in a stepwise manner. ing. As shown in the plan view of FIG. 14, the transducer 1 has a rectangular shape, and a plurality of transducers 1A are arranged in an array.

At the time of transmitting a wave, by simultaneously exciting several oscillators 1A at the center of the transmitter / receiver 1, a transmitting beam U spreading in a conical shape as shown in FIG. 1 is obtained.
When receiving the echo, a given amount of delay or phase shift is given to the received signal of each transducer 1A between adjacent transducers, so that the echo signal can be received from a specific direction.
As a result that the phases of the received signals of the transducers 1A are aligned, a received beam R is formed in the specific direction. Therefore, by continuously changing the delay amount, the signal passes directly below the transducer 1 and
In addition, the reception beam R is scanned over a band-shaped region S1 extending in the transducer array direction of the transducer ₁ .

Reference numeral 2a denotes a transducer driving unit for driving the motor M. 3 is each transducer 1A of the transducer 1
Is a transmission unit that supplies a drive signal for transmitting an ultrasonic wave to the device, and supplies a drive signal capable of obtaining a wide range of directivity. Reference numeral 4 denotes a receiver for amplifying and detecting the signal received by the transmitter / receiver 1 and for giving a predetermined delay amount to each detection signal from each transducer 1A in order to scan the reception beam as described above. Department. Reference numeral 5 denotes a transmission / reception system control unit that controls the transmission unit 3 and controls the above-described reception unit.

Reference numeral 6 denotes an A / D converter for converting a received signal obtained from the receiving section 4 from analog to digital. The converted digital signal is stored in a buffer memory 7. Reference numeral 8 denotes a coordinate conversion unit for converting the data D (r, θ) in the polar coordinate system into the data D (X, Y) in the rectangular coordinate system. The converted data is a vertical sectional image memory in a two-dimensional array. 9 and the vertical section image video memory 9a.
The A / D converter 6, buffer memory 7, and coordinate converter 8 operate in synchronization with the clock from the transmission / reception system controller 5.

Reference numeral 10 denotes a sampling circuit. When data for one vertical section is stored in the vertical section image memory 9, data is read out from the vertical section image memory 9 line by line in the depth direction, and each line is read. The address when detecting the peak value of the data (sea depth) or its peak value, the address when detecting the peak value from the data excluding the peak value (the depth of the underwater object), and the previous peak value
(Echo level from the sea floor). 11A is a seafloor data memory for storing the echo level and seafloor depth of the sampling circuit 10, and 11B is an underwater data memory for storing the echo level and the depth data of the underwater object.

Reference numeral 12 denotes a display system control unit, and an operation unit 13
Based on the various display data input and set, the setting data such as the turning range and the depth are supplied to the transmission / reception system control unit 5, and the sampling range (depth) is supplied to the sampling circuit 10. Further, a memory 12a for storing data from the seafloor data memory 11A and data from the underwater data memory 11B, and a color tone table 12b for displaying seafloor data (level, depth) and underwater data (level, depth) are provided. The 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 receives signals for characters and symbols to be displayed on a display 19 described later. Send out. Creation of image data according to the present invention will be described later in detail. Reference numeral 16 denotes a PPI image video memory that stores display data of the PPI image created by the PPI drawing unit 14, and 17 denotes a character / symbol that stores character and symbol image data created by the character / symbol drawing unit. Image video memory.

Reference numeral 18 denotes a video signal converter, which converts the video data from each of the video memories 9a, 16 and 17 into color data or density data for each depth. Reference numeral 20 denotes each of the video memories 9a, 16, 17 and the video signal conversion unit 18.
Is a video clock unit for supplying a clock to the video clock.

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, in step S1, the depth range L to be searched is
Information such as ₁ to L ₂ (see FIG. 16) and the step turning angle of the transducer 1 is input. As L ₂ , a value larger than the depth of the seabed Z that is roughly known as shown in FIG. 16 is adopted. In the next step 3, the transmission is performed, and in step S4, the narrow-directional reception 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 Minute data is read. The data for one line corresponds to each received beam R. FIG. 16 shows a polar coordinate system, while FIG. 17 shows an orthogonal coordinate system.

In step S7, the current level peak value and the current depth (sea bottom depth) are detected, and in step S8, the level peak value and depth data are stored in the sea bottom data memory 11A. In step S9, all lines
It is determined whether the reading of (1 vertical section fraction) has been completed,
The loop of steps S6 to S8 is repeated until reading of all lines is completed.

When reading of all lines is completed for one vertical sectional image, steps S9 to S10 are performed.
Then, from the data in the seafloor data memory 11A, the seafloor depth L ₀ (see FIG. 16) immediately below the ship Q is recognized. In the next step S11, L ₂ = L ₀ −α as an accurate depth L _2.
= L ₂ 'is adopted.

In the next step S12, the data is read out again from the vertical sectional image memory 9 line by line in the depth direction.
Since the depth range at that time is L ₁ or L ₂ (= L ₀ −α), only the echo data from the underwater object is read out,
In step S13, the level peak value and the depth data are detected, and in step S14, the underwater data memory 11B
Is stored. Then, the flow of steps S12 to S14 is executed until data is read from all lines.

When the data reading for all the lines has been completed in this way, steps S15 to S16
The display system controller 12 superimposes the echo level on the depth data for one vertical section image. The processing in step S16 will be described in detail with reference to the subroutine in FIG.

In step S21, the seafloor data memory 11
When the seafloor data of A is read into the display control unit 12,
The seabed depth L ₀ determined for the one vertical sectional image as a reference in the next step S22, the amount of change ΔD depth in the one vertical cross section image is calculated. Next step S2
In 3, a weight is set for the variation ΔD as a measure against the sway of the ship. As the weight value, for example,
A value is adopted in which the weight of "1" directly below own ship Q decreases linearly to "0.3" on both sides.

In parallel with this, the level data memory 11
When the level data is read from C into the display system control unit 12, the process proceeds from step S24 to step S26, where the level data is subjected to horizontal TVG gain correction in order to correct the level data regardless of the depth. You. 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.

Referring back to FIG. 15, in step S17, the color tone table 1 is set based on the superimposition data for one vertical section image.
PPI drawing referring to 2b is performed, and step S18 is performed.
Then, it is determined whether the PPI drawing is completed. Until the completion, the process returns from step S18 to step S2, and after the transducer 1 is turned by the step angle, the above-described operation is repeated to display on the display 19. The sea floor is displayed as a PPI image.

FIG. 19 shows a display example of the present apparatus. The seabed is displayed as the background color with the level data. A tall protrusion is displayed as a level data with a depth change amount superimposed thereon. The fish school is displayed based on the fish school data (depth or signal level). A low protrusion at a position distant from the position of the ship (having a large angle of incidence) is displayed mainly based on the level data because the amount of change in depth (a large error due to the motion of the hull) is suppressed by the weight function.

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 is displayed in different colors according to its depth or echo level so that the display of the school of fish and the seabed can be clearly distinguished from each other. It is good to display by change.

When the ship shakes, the error in the depth data increases as the search area becomes farther from immediately below the ship. Therefore, a weight function is set to the depth data as described above,
By attenuating the signal level in a region distant from immediately below the ship and compensating for the signal level, the error caused by the sway of the hull as described above can be reduced.

In this flow, the vertical sectional image memory 9 is used.
After the data read from and the data processing are completed, the process proceeds to the next rotation of the transducer 1 and the transmission and reception.
Actually, by having two memories, transmission / reception and data processing are performed in parallel.

The embodiment described above (corresponding to FIGS. 9 and 10) uses the display base as the signal level, but the second embodiment of the present invention uses the display base as the depth.
(Corresponding to FIG. 11) will be described. Display system controller 12 in that case
FIG. When the level data of one vertical section is taken into the display system controller 12 from the seafloor data memory 11A in step S31, the process proceeds from step S31 to step S32, where the level data is subjected to horizontal TVG gain correction, and the next step is performed. 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 controller 12, the process proceeds from step S34 to step S35, where a weight is set for the change amount ΔD as a measure against the sway of the ship. In step S36, the level change amount ΔR is superimposed on the depth data, and the superimposed data is PP
It is supplied to the I image drawing unit 14.

In the above embodiment, two types of signals are superimposed. FIG. 21 shows a third embodiment of the present invention. If detected, in step S42, one of the depth data is read from the seafloor data, and in step S4
In 3, the amount of change is detected from the depth data, and a weight is set for the amount of change as a measure against the sway of the ship, and the PP is set in a color tone corresponding to the set amount of weight.
On the other hand, level data is read out of the seafloor data in step S45 while I drawing is performed, and in step S46,
The horizontal TVG described above is set, and based on the data,
For example, PPI drawing is performed in monotone as a background. In this display example, the projection has a large difference in elevation.

FIG. 22 shows a fourth embodiment of the present invention. When the seafloor data of the level and the depth is detected in step S51, one level data is read from the seafloor data in step S52. Is performed, and step S53 is performed.
In step S54, the horizontal TVG is set. In step S54, the amount of change is detected from the level data, and PPI rendering is performed in a color tone corresponding to the amount of change. In step S55, depth data is read out of the seafloor data. , Step S
At 56, the above-mentioned weight is set, and PPI drawing is performed as a background, for example, in monotone based on the data. In this display example, it is a projection having a small height difference, that is, an artificial reef or the like.

[0040]

As described above, the echo level from the water depth and the water bottom is detected in a wide range, the amount of change in the water depth with respect to the reference value is obtained, and the amount of change is superimposed on the echo. Since the PPI is drawn on the display based on the data obtained, the projection is clearly displayed regardless of the height or position of the projection on the water bottom. In this case, since the signal level is displayed based on the display level, as in a fish finder which is already frequently used, the displayed image is easily captured visually. Further, in the second embodiment of the present invention, the amount of change of the echo level with respect to the reference value is obtained, and the PPI is drawn 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 a "detection device." Further, in the present invention, the depth error due to the sway of the hull is reduced by simply setting the weight to the detected depth, and an expensive and complicated sensor is not required. As in the third and fourth embodiments of the present invention, the same effect can be obtained even if depth data or PPI drawing is performed based on the amount of change in level data.

[Brief description of the drawings]

FIG. 1 is a diagram showing transmitted and received beams in an underwater probe

FIG. 2 is a diagram showing a search area when the transducer used in FIG. 1 is turned.

FIG. 3 is a display diagram showing a display example of a seabed obtained by an underwater detection device.

FIG. 4 is a diagram showing a modification of the search method of FIG. 1;

FIG. 5 is a display diagram showing a display example of a school of fish obtained by the underwater detection device.

FIG. 6 is a display example in which one vertical cross-section is described in addition to the PPI display of the seabed and the school of fish.

FIG. 7 is a display example when PPI drawing is performed based on water depth information indicated by a cross-sectional image.

FIG. 8 is a display example when the height of the protrusion is low and the hull is shaken in FIG.

FIG. 9 is a diagram corresponding to claim 1.

FIG. 10 is a diagram showing another operation mode of FIG. 9;

FIG. 11 is a diagram corresponding to claim 2.

FIG. 12 is a control block diagram showing an embodiment of a water bottom exploration device of the present invention.

FIG. 13 is a diagram showing a transducer used in the apparatus shown in FIG. 12 and its driving unit;

FIG. 14 is a plan view of the transducer shown in FIG. 13;

FIG. 15 is a flowchart showing a control operation of the apparatus shown in FIG. 12;

FIG. 16 is a diagram showing an underwater state detected by one scan by the transducer of FIG. 12;

FIG. 17 is a diagram showing reading of data stored in the vertical sectional image memory of FIG. 16;

FIG. 18 is a subroutine showing details of the first embodiment with respect to step S16 in FIG.

FIG. 19 is an example of a PPI drawing obtained by the water bottom exploration apparatus of FIG.

20 is a subroutine showing details of a second embodiment with respect to step S16 in FIG.

FIG. 21 is a flowchart showing control performed in a third embodiment of the present invention.

FIG. 22 is a flowchart showing control performed in a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmitter / receiver 2 Transmitter / receiver turning mechanism part 2a Transmitter / receiver driving part 3 Transmitter 4 Receiver 5 Transmitter / receiver controller 6 A / D converter 7 Buffer memory 8 Coordinate converter 9 Vertical cross section memory 9a Vertical cross section Video memory 10 Sampling circuit 11A Undersea data memory 11B Underwater data memory 12 Display system control unit 12a Memory 12b 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 (8)

[Claims] An ultrasonic wave is transmitted / received using a transmitter / receiver, an echo level from a water depth and a water bottom in a wide area around the transmitter / receiver is detected, and a change amount of the water depth with respect to a reference value is obtained. And a display unit for displaying a flat image on a display based on data obtained by superimposing the amount of change on the echo level signal. 2. Transmitting and receiving an ultrasonic wave using a transducer, detecting an echo level from a water depth and a water bottom in a wide area around the transducer, and calculating a change amount of the echo level with respect to a reference value. And a display device for displaying a flat image on a display based on data obtained by superimposing the variation on the water depth data. 3. A transmitter / receiver that transmits an ultrasonic wave toward a water bottom, scans a directional receiving beam, and receives an echo signal from an area spreading in a fan shape below the ship. By repeating the operation of the transmitting and receiving waves every time the transducer is turned at a predetermined step angle, in a water bottom exploration device for exploring a wide area around the own ship, Detects the level of the echo, finds the amount of change in the water depth relative to the reference value,
A water bottom exploration apparatus characterized in that the change amount is displayed as a plane image on a display device based on data obtained by superimposing the change amount on the echo level. 4. A transmitter / receiver that transmits an ultrasonic wave toward the water bottom, scans a received beam, and receives an echo from an area spreading in a fan shape below the own ship. By repeating the operation of the transmitting and receiving waves each time the vessel is turned at a predetermined step angle, in a water bottom exploration device that searches a wide area around the own ship, the depth of the water from the echo signal and the level of the echo from the water bottom are determined. A water bottom exploration apparatus, comprising: detecting a change amount of the echo with respect to a reference value; and displaying the change amount on a display device as a plane image based on data obtained by superimposing the change amount on the water depth data. 5. The depth data according to any one of claims 1 to 4, wherein a weight of the depth data is set such that a numerical value decreases as the distance from the position directly below the ship increases in order to reduce an error in the depth data caused by the motion of the hull. A water bottom exploration device according to item 1. 6. An underwater object is displayed on the display device by detecting an echo from the underwater object or its depth.
5. The underwater exploration apparatus according to any one of 5. 7. A transmitter / receiver for transmitting an ultrasonic detection signal in a wide range direction toward the bottom of the water using the transmitter / receiver, and then scanning the directional received beam to receive an echo signal. Then, a vertical cross-sectional area extending below the transducer is searched, and the operation of the transducer is repeated every time the transducer is rotated at a predetermined step angle, so that a wide area around the transducer is obtained. An underwater exploration apparatus for exploring, wherein a depth and an echo level of an underwater object are detected from the echo signal, and the water bottom is displayed as a plane image on a display based on the depth and the echo level. 8. A transmitter / receiver for transmitting an ultrasonic detection signal in a wide range direction toward the bottom of the water using the transmitter / receiver, and then scanning the directional received beam to receive an echo signal. Then, a vertical cross-sectional area extending below the transducer is searched, and the operation of the transducer is repeated every time the transducer is rotated at a predetermined step angle, so that a wide area around the transducer is obtained. An underwater exploration device for exploration, comprising: an echo level signal output unit that outputs a signal representing an echo level from the bottom of the water; and a depth signal generating unit that generates a signal representing the depth of the bottom of the water from the echo signal. An underwater exploration apparatus characterized in that the underwater floor is displayed in color as a plane image on a display based on an output signal of an output means and an output signal of a depth signal generation means.