JP4106124B2 - Automatic fish tracking tracking sonar - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a scanning sonar, an automatic fish tracking scanning sonar particularly have a function of target can be automatically tracked.
[0002]
[Prior art]
In fishing rods, it is important not only to know the position of the school of fish, but also to know in what direction and at what speed the fish school is moving in order to set up the net. It is necessary to have a device with the function to do this. For example, there is "Target-scanning type scanning sonar" of No. 7-19020, which is outlined below.
[0003]
First, by looking at the detection image displayed on the monitor, an event mark is attached with the target fish center as the target with the highest display density. As a result, a tracking detection area centered on the event mark is set, and beam scanning is performed so that the beam center faces the event mark. With respect to the detection signal obtained by this beam scan, a portion having the highest level in the area is selected, an event mark is replaced at that portion, and a tracking detection area is newly set for the event mark. . The target center is automatically tracked by repeating the beam scanning operation toward the newly determined event mark.
[0004]
As shown in FIG. 1, the scanning sonar transmits ultrasonic waves in all directions toward the seabed from a transducer 1 attached to the bottom of the ship, and receives echoes by the ultrasonic transducer 1. At this time, if a receiving beam R having a sharp directivity angle as shown in the figure is formed and swiveled (horizontal scanning) while maintaining the angle θ with respect to the sea surface (this angle is called a tilt angle), the receiving beam is received. The wave beam R scans along the cone surface U. Thereby, the echo from the fish school etc. which were located on the cone surface are detected in an order from the near thing. If the tilt angle θ is locked in the target direction, the target can be tracked.
[0005]
The scanning sonar of this publication does not describe the target trajectory display or moving speed, but it is possible to know the trajectory display, moving direction and moving speed by plotting the target position at fixed time intervals. Such a system has already been put into practical use. FIG. 2 shows a trajectory display example of such a system. The center of the screen is the ship position, and X is the image of the school of fish set as the target. L is the trajectory of the fish school X. The direction of the fish mark P drawn at the center of the fish school X indicates the current movement direction of the fish school X. In the lower right of the screen, the moving speed and moving direction of the fish school X are shown. Looking at this trajectory L, the school of fish X is moving as if it were wandering, but it is not actually moving like that, and the cause of this display is due to the ship's hull shaking. It is. As can be seen from the locus L, the direction of the mark P changes every moment.
[0006]
[Problems to be solved by the invention]
Because of such a confusing display, the true movement trajectory and movement direction of the fish school X cannot be known. Although it is possible to detect the shaking of the hull and correct the detected echo signal to eliminate the shaking, it is technically difficult to detect the shaking in three directions in the hull and correct the echo signal. In addition, since the echo slightly fluctuates due to a slight change in the beam angle, even if complete correction can be performed, it is not possible to completely eliminate the influence caused by the fluctuation.
[0007]
Further, in the above publication, when the center of the fish school X is detected, it is set as the maximum signal level. However, when the detection signal is abnormally strong and the signal is saturated, the center of the fish school X is selected. It becomes impossible to detect accurately, so that accurate target tracking cannot be performed. For example, in FIG. 3, J indicates the own ship, and W indicates the above-described area. If the fish group X ₁ tracked in the area W is lost, the target object suddenly shifts to the fish group X ₂ , and FIG. As shown in FIG. ₂ , the fish group X ₂ is set as a tracking target. In that case, as shown in FIG. 5, it is necessary to re-specify the target from X ₂ to X ₁ , and in that case, the trajectory L up to that point is cleared, and it is necessary to start over from the beginning.
[0008]
The present invention has been made to solve the above-described problems, and provides a scanning sonar that can accurately know the moving speed, moving direction, and moving trajectory of a target and has high tracking ability of the target. For the purpose.
[0009]
[Means for Solving the Problems]
In the conventional system described above, a misleading display is output in order to display the detection result as a locus as it is. The hull oscillation period is generally a few seconds or so. Therefore, every time a predetermined time elapses or every time a school of fish moves a predetermined distance, if it is output on the screen, that is, if a dead zone that does not output detection data is provided, it will cause fluctuations that occur within a short time. The associated false detection data can be eliminated.
[0010]
If a fixed time is set as a dead zone, the fish position is displayed almost accurately each time the fish moves at a low speed. However, if the hull is shaken during data detection, the fish The direction of movement is not determined and the exact direction of movement is not displayed. Therefore, in the present invention, as shown in claim 2 , each time the target center passes a certain time, either one of the moving speed or moving direction of the target is calculated from the first and last position data of the target center. it's shown.
[0011]
The target moving speed is calculated by the moving distance and the time required for the movement. However, the shorter the distance and the time, that is, the instantaneous speed changes greatly and a stable result cannot be obtained. Therefore, using a speed obtained by averaging the instantaneous speed over a predetermined time provides a stable and easy-to-see result. Here, the time required for the movement is ensured to be equal to or longer than a predetermined time , thereby providing an averaging effect . The same means was used for the moving direction.
[0012]
As means for knowing that the school of fish has moved a certain distance in a straight line from the movement source point, in claim 1 , as shown in FIG. 15, which will be referred to in detail later, a predetermined size is set so that the center of the target Xa is located at the center. Area W ₁ is set, and it is detected whether the target center has deviated from the area W ₁ .
[0013]
As shown in FIG. 6, when the fish school X moves away from its own ship J without changing its size, the beam diameter of the received beam R also increases. Is displayed as the distance from own ship J increases. Therefore, it is necessary to increase the size of the area W provided as means for knowing that it has moved a certain distance, as shown in claim 3.
[0014]
Since the area W ₁ shown in FIG. 15 is for knowing the moving distance of the fish school Xa, the area does not move even if the fish school Xa moves. Therefore, in order to track the fish shown in Xb in the area W within ₁ it is provided with a sub-area w for tracking moving to follow the movement. In order to distinguish this, the previous area W ₁ is referred to as a main area.
[0015]
The fish echoes in the main area W ₁ are binarized at the obtained level. When the binarized data chunk is expanded (filling out the missing part) and there are a plurality of target candidates, that is, data chunks, the data chunk is narrowed down to one by feature extraction. After narrowing the data chunk to one, the center of gravity of the data chunk is obtained and set as the center of the target.
[0016]
Here, the target echo selection and the means for preventing misidentification tracking will be described.
(Target echo selection)
The following parameters are set to identify the fish echo.
Area: A, distance: L, strength: S, aspect ratio: R
A weighted sum is defined as a feature value.
Feature P = αA + βL + ηS + γR
For example, set the weight as follows,
In the judgment formula 1, α: β: η: γ = 1: 4: 2: 1
In judgment formula 2, α: β: η: γ = 4: 3: 2: 1
A judgment formula suitable for the target is selected, and a feature amount P is obtained.
Select the highest feature value.
(Preventing misidentification tracking)
In some cases, the target echo may be interrupted without being received. In this case, a filter is provided to prevent misidentification tracking of other targets.
1. If the speed limit filter target is lost and other targets are misidentified and tracked, the instantaneous speed moved will be large. By providing a limit speed, it is possible to prevent misidentification tracking.
2. In the case of an acceleration limiting filter target, it is usually moving at a constant speed, and the change in speed, that is, the acceleration is usually below a certain level. Therefore, false tracking can be prevented by providing a limit acceleration.
[0017]
In the present invention, the fish quantity value is obtained in order to quantify the scale of the school of fish, and the calculation method will be described in detail later using mathematical expressions.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 7 is a control block diagram showing an embodiment of the scanning sonar of the present invention. Reference numeral 1 denotes a transmitter / receiver in which a large number of ultrasonic transducers are arranged in a cylindrical shape, and reference numeral 2 denotes a drive circuit that excites the transmitter of the transmitter / receiver 1. A vertical beam combining circuit 3 forms a received beam having a desired tilt angle by setting a predetermined delay for each signal received by the longitudinal ultrasonic transducer array. 4 is a horizontal beam forming circuit for setting a predetermined delay with respect to a signal obtained by the ultrasonic transducer array in the horizontal direction in order to obtain a beam having a desired direction from the beam formed by the vertical beam synthesis circuit 3. It is. By this vertical beam synthesis and horizontal beam synthesis, the received beam R having a sharp directivity shown in FIG. 1 is formed.
[0019]
Reference numeral 5 denotes a coordinate conversion circuit that converts a received beam signal obtained from the horizontal beam forming circuit 4 from a polar coordinate system to an orthogonal coordinate system. Reference numeral 6 denotes an A / D device that performs A / D conversion on the signal. The A / D converted signal is stored in the screen storage memory 7. The signal in the screen storage memory 7 is sent to the monitor 9 through the signal adder 8 and displayed on the screen. The above circuit configuration is a general scanning sonar configuration.
[0020]
Reference numeral 10 denotes a CPU for causing the configuration of the present invention to perform the functions of the present invention. In the signal adder 8, a frame of a main area, which will be described later, is superimposed on the data of one screen from the screen storage memory 7, and the data is sent to the monitor 9 and sent to the fish recognition unit 11. . The fish recognition unit 11 recognizes a fish school as will be described later. Reference numeral 12 denotes a fish school selection unit that selects a target fish school from among a plurality of recognized fish schools. By sending the target fish school data to the target center detector 13, the target center detector 13 determines the center of the fish school from the position of the center of gravity as described above. Reference numeral 14 denotes a distance calculation unit that calculates the distance from the ship position to the center of the school of fish. A sub-area size / position setting unit 15 determines the size of the sub-area based on the distance and determines the position of the sub-area based on the center position of the fish school. The sub-area size / position setting unit 15 can also be set to an arbitrary position with the cursor. . Reference numeral 16 denotes a tilt angle calculation unit that calculates a tilt angle at the time of the next reception beam formation from the current position data of the fish school center, and the obtained tilt angle is sent to the vertical beam synthesis circuit 3.
[0021]
Reference numeral 17 denotes a main area outside determination unit that determines whether the fish school center is outside the main area. Reference numeral 18 denotes a main area setting unit for newly setting a main area based on data set by the sub area size / position setting unit 15 when the fish center is outside the main area. Set a main area of the same size as it.
[0022]
Reference numeral 19 denotes a target speed calculation unit that calculates the movement speed of the school of fish from the movement of the target center. Reference numeral 20 denotes a speed correction unit that corrects the obtained moving speed with the ship speed input from the outside and the traveling direction of the own ship, and calculates the true moving speed (ground speed) of the school of fish. Reference numeral 21 denotes a fish quantity value calculation unit for calculating the fish quantity value of the selected fish school, and reference numeral 22 denotes a trajectory creation part for obtaining the trajectory from the movement of the fish center, and these data are supplied to the monitor 9. .
[0023]
The control operation of this apparatus having the above configuration will be described with reference to the flowchart of FIG. In step S1, ultrasonic waves are transmitted from the transmitter / receiver 1 in all directions, and the echoes are received by the formed received beam, stored in the screen storage memory 7, and as shown in FIG. Echoes are displayed as fish schools X ₁ and X ₂ . Located at the center is the own ship position J.
[0024]
Looking at the monitor screen in step S2, determines the fish X ₁ targeting, and instructs the center O of the fish X ₁ on the monitor with the cursor, in step S3, the main area around the fish X ₁ W ₁ and a sub-area w having the same size are set. However, the monitor only the main area W ₁ is displayed. The size of the main area W ₁ changes in proportion to the distance from the own ship J to the fish school X ₁ .
[0025]
If the next transmission timing, the process proceeds from step S4 to step S5, reception beam is to be directed to fish X _1, the tilt angle is set. In FIG. 10, when the ship is at the position indicated by J, the received beam R ₁ is set to the tilt angle T ₁ (or vertical scan within the range of T ₁ ), and the ship is to the position indicated by J ′. When advanced, the received beam R ₂ is at a tilt angle T ₂ . Z in FIG. 10 is a mark displayed for confirming the fish center O designated in FIG. 9, and changes to a fish mark when movement of the fish school X ₁ is detected as will be described later.
[0026]
In step S6, the wave is transmitted again, and an echo is received, stored and displayed. The display at this time is shown in FIG. Here, only the front side of own ship J is shown enlarged. The movement of the fish school X ₁ to the upper right with respect to the main area W ₁ is due to the movement of the fish school X ₁ , the swaying of the own ship J, or both factors. In the next step S7, the school of fish present in the subarea w is recognized.
[0027]
In step S8, when there are a plurality of recognized fish schools, the target fish school is selected from them.
[0028]
In the next step S9, the center of the target fish school X1 is detected by detecting the center of gravity as described above. FIG. 12 shows another method for detecting the center of a school of fish. (A) of FIG. 12 shows a fish X1 in the main area W1, upon obtaining the center of the fish X1, calculates the average level of definitive to each pixel of the fish X1, (B), the average Only dot data exceeding the level is extracted, and as shown in (C), the smallest quadrangle surrounding those data is assigned, and the center O of the quadrangle is set as the center of the fish school X1.
[0029]
In the next step S10, as shown in FIG. 13, the sub-area w is moved so that the fish center O is located in the center, and the size of the sub-area w is proportional to the distance from the own ship J to the fish center O. To change.
[0030]
In step S11, Sakanaryou value Q is calculated in order to quantify the size of fish X _1, are displayed on the monitor as shown below. A method for obtaining the fish quantity value Q will be described with reference to FIG. The total number of dots in the sub-area w is S, the level of each dot is 16 levels (L _{1 to} L ₁₆ ), the number of dots of the level Lx is nx,
Fish quantity value Q = (n ₁ L ₁ + n ₂ L ₂ +... + N ₁₆ L ₁₆ ) / S
Ask for.
[0031]
Step S12, fish center O is the main area W ₁ or the external is determined. In FIG. 15, when the fish school that was at the position of Xa has moved to the position of Xb (at this time, the sub-area w has moved from position (1) to position (2)), the school of fish is the main area W _1. Since it is within, the process proceeds from step S12 to step S15.
[0032]
On the other hand, fish (moved in ▼ subarea w position ▲ 3) is when moved to the position of Xc, the process proceeds from step S12 since the main area W ₁ outside step S13, the position ▲ 1 ▼ main area W ₁ of , Move to position {circle around (3)}, and its size is also made the same as that of the sub area w, so that the main area and the sub area again coincide. In this way, the sub area w moves following the movement of the fish center O, but the main area W ₁ moves only when the fish center O is out of the area.
[0033]
In step S14, the locus of fish X ₁ is displayed from the movement between two points of said. FIG. 16 shows the trajectory L of the fish school X ₁ , and L ₁ , L ₂ ,... Indicate movement between two points. Further, the moving direction of the fish school X ₁ is also displayed in the direction of the fish mark P. As can be seen by displaying the trajectory in FIG. 2, the mysterious movement trajectory of the fish school X _{1 due} to the fluctuation of the hull is not displayed.
[0034]
In step S15, it is determined whether the display timing of speed and direction has come. For example, each time 30 seconds, 45 seconds, or 60 seconds have passed, the process proceeds to step S16, and as shown in FIG. The moving speed V and the moving direction D are displayed on the monitor 9 from the distance d and the direction θ.
[0035]
In the present invention, the center detection of the school of fish is not caught at the highest level (one point), but is caught in the region as shown in FIG. 7, so the center detection accuracy is high. Therefore, in FIG. 3 and FIG. As shown, it is rare to lose sight of the target school of fish. Even if it is missed, as shown in FIG. 18, when the target is returned from X ₂ to X ₁ , the trajectory L of the fish school X ₁ so far is displayed as it is, which is convenient.
[0036]
【The invention's effect】
As described above, the present invention does not display the detection result as it is, but outputs it to the screen every time the school of fish moves a certain distance, for example. Change data is eliminated, and the movement trajectory and direction of the school of fish can be accurately displayed.
[Brief description of the drawings]
FIG. 1 is a diagram showing the formation of a received beam in a scanning sonar. FIG. 2 is a diagram showing a movement trajectory of a school of fish displayed by a conventional device. FIG. 3 is a diagram showing a fish school X ₁ targeted by a conventional device. Figure showing the situation when it was lost [Figure 4] Figure showing the situation where another fish school X ₂ was targeted [Figure 5] Figure showing the situation when re-designating the target [Figure 6] From own ship FIG. 7 is a diagram showing how the size of the main area W changes according to the distance to the fish school. FIG. 7 is a diagram showing detection of the fish center. FIG. 8 is a control block diagram showing one embodiment of the present invention. FIG. 10 is a flowchart showing the control operation of the apparatus of FIG. 8. FIG. 10 is a diagram showing how the fish center is indicated by the apparatus of the present invention. FIG. 11 is a diagram showing the setting of the tilt angle. Fig. 13 shows the movement of a school of fish [Fig. 13] Following the movement of a school of fish Figure 16 shows the sub-area showing a state when a fish from Figure [15] main area W ₁ used in the description of the operation of FIG. 14 is a fish quantity value showing a state in which movement is moved Te FIG. 17 is a diagram showing how the trajectory and the moving direction are obtained from the movement of the main area. FIG. 17 is a diagram showing the trajectory displayed by the apparatus of the present invention. Figure showing the situation [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Transmitter / receiver 3 Vertical beam synthesis circuit 4 Horizontal beam synthesis circuit 7 Screen storage memory 9 Monitor 10 CPU
DESCRIPTION OF SYMBOLS 11 Fish school recognition part 12 Fish school selection part 13 Target center detection part 14 Distance calculation part 15 Subarea size / position setting part 16 Tilt angle calculation part 17 Out of main area determination part 18 Main area setting part 19 Target speed calculation part 20 Speed correction part 21 Fish Quantity Calculation Unit R Received Beam X Fish School J Own Ship W Main Area w Sub Area

Claims (7)

In the scanning sonar that automatically detects the target by detecting the center of the target from the level intensity of the echo signal from underwater and determining the transmission beam at the target center,
A main area of a predetermined size is set so that the detected target center is located in the center, and the position of the main area is fixed as long as the target center detected thereafter is present in the main area. When it is determined that the target center is out of the main area, the main area is moved again so that the target center is located at the center. At this time, the target center moves from the center of the main area to the outside of the main area. automatic fish tracking scanning sonar, characterized by displaying the moving trajectories of the target from the moving data between the points.  The automatic fish tracking tracking sonar according to claim 1, wherein the moving speed or moving direction of the target center is displayed at desired time intervals.  3. The scanning sonar according to claim 2, wherein the size of the main area is changed in proportion to the distance from the ship.  When obtaining the center of the fish school as the target center, the data in the main area is binarized at a level that can be selected by the user, and the data group of “1” is expanded to a lump corresponding to the fish echo, and the fish school If there are multiple echoes, the area of the fish echo, the distance from the previous target center, intensity, and aspect ratio are calculated, and the sum of the weights that can be set by the user is used as the feature value, and the largest is extracted. The automatic fish tracking scanning sonar according to any one of claims 1 to 3, wherein one is selected by feature extraction, and the center of gravity of the selected fish echo, that is, the data group of '1' is set as the fish center.  The automatic fish tracking tracking sonar according to any one of claims 1 to 4, wherein the center of gravity of the target is calculated and the center of gravity is set as the target center. When determining the target center, a sub area for target tracking is set separately from the main area, and in order to quantify the scale of the school of fish, S is the total number of dots detected in the sub area, Are classified into L ₁ to Lx, and the number of dots of level Lx is nx,
The automatic fish school tracking scanning sonar according to claim 1, wherein the fish quantity value = (n ₁ L ₁ + n ₂ L ₂ +... + NxLx) / S is obtained. In a scanning sonar that automatically tracks the school of fish by detecting the center of the school of fish from the level intensity of the echo signal from underwater and determining the transmission beam at the center of the school of fish,
A main area of a predetermined size is set so that the detected fish center is located in the center, and as long as the subsequently detected fish center exists in the main area, the position of the main area is fixed, and the fish center is When it is determined that the fish center is out of the main area, the main area is moved again so that the fish center is located at the center. At this time, the fish center moves from the center of the main area to the outside of the main area. to display the fish school of movement trajectories from moving data between points,
When determining the fish center, the data in the main area is binarized at a level that can be selected by the user, and the data group of '1' is expanded to a lump corresponding to the fish echo, and there are multiple fish echoes. In this case, the feature extraction is to calculate the area of the fish echo, the distance from the previous fish center, the intensity, and the aspect ratio, and add the weights that can be set by the user as feature amounts, and extract the maximum one. An automatic fish tracking scanning sonar that selects one according to, and sets the center of the selected fish echo, that is, the data group of '1' as the fish center.

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