JPH04285881A - Scanning sonar forming mean detection image - Google Patents

Abstract

PURPOSE:To obtain scanning sonar capable of performing plane averaging processing even at the time of the revolution of a transmitter-receiver. CONSTITUTION:Scanning sonar has an angle-of-revolution detector 7 detecting the direction of a transmitter-receiver 1 with respect to a predetermined direction as a first drift angle gamma and two or more signal processing memories 4,5 for storing echo data to which addresses are alotted at every second drift angle gammashowing deviation with respect to the predetermined direction. Further, an address control part 6 converting each detecting direction of the transmitter- receiver in each transmitting-receiving timing to the second drift angle on reference to the first drift angle and outputting the addresses N of the respective memories corresponding to the converted second drift angle, a data writing part 11 renewing the oldest echo data stored in the memories 4,5 according to the address outputted from the address control part on the basis of the echo data received by the transmitter-receiver and an averaging operation part 12 calculating the average value of the echo data at every same address of the respective memories to output the same as a detection image signal are further provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning sonar that detects underwater using ultrasonic waves at approximately periodic timing by rotating a transducer.

0002

2. Description of the Related Art FIG. 3 is a block diagram showing a conventional example of this type of scanning sonar.

The transducer 21 is rotated by a rotation mechanism 28 . The oscillation signal of the transmitter 29 is given to the transducer 21 via the switch 22 and output as an ultrasonic wave. The ultrasonic echo signal is received by the receiving section 23 via the transducer 21 and the switch 22. The receiving section 23 amplifies and processes the received echo signal. The above data is stored in the designated address of the signal processing memory 24 designated by the timing control circuit 30 in accordance with the timing designated by the write control circuit 31. When storing data, the signal processing memory 24 outputs the data stored at the previous transmission/reception timing to the signal processing memory 25. Signal processing memory 2
5 stores data from the signal processing memory 24 at a designated address. The average calculation unit 32 includes the signal processing memory 2
An average value is calculated for each of the 4th and 25th addresses and sent to the display as a surface average output.

0004

[Problems to be Solved by the Invention] In the above-mentioned conventional scanning sonar, when the transducer is rotated, the contents of the signal processing memory for calculating the area average change, and the image of the target such as a school of fish changes. The problem is that it becomes smaller, weaker, or in severe cases disappears.

[0005] Therefore, since the effect of extracting only the target by area averaging is lost, the area averaging operation had to be stopped when the transducer was turned.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a scanning sonar capable of extracting a target by area averaging even when the transducer is rotating.

[0007]

[Means for Solving the Problems] The scanning sonar of the present invention includes a turning angle detection device that detects the orientation of a transducer with respect to a predetermined direction as a first declination angle, and a turning angle detection device with respect to the predetermined direction. 2 for storing echo data, which is assigned an address for each second deviation angle indicating the deviation.
The above memory and each detection direction of the transducer at each transmission/reception timing are converted to a second declination angle by referring to the first declination data, and each memory corresponding to the converted second declination angle is stored. An address control unit that outputs an address, a data writing unit that updates the oldest echo data stored in the memory according to the address output by the address control unit using the echo data received by the transducer, and and an average calculation unit that calculates the average value of echo data for each address and outputs it as a detected image signal.

[0008]

[Operation] The angle detection device detects the direction of the transducer as a first declination angle. The address of each memory is set for each second deflection angle corresponding to the magnitude of deviation from a predetermined direction.

At each transmission/reception timing, the address control section sets each detection direction of the transducer to a second direction using the first declination angle.
Convert to each memory address corresponding to the argument. The oldest echo data stored in the memory is updated with the latest echo data according to the address from the address control unit. An average calculation unit uses the echo data for each address in each memory to calculate the average value of the echo data for each second declination angle, and outputs the average value as a detected image signal.

0010

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a scanning sonar according to the present invention, and FIG. 2 is a diagram showing first and second deflection angles.

Transducer/receiver 1, switching device 2, receiving section 3, signal processing memories 4, 5 (hereinafter referred to as memories 4, 5), turning mechanism 8, transmitting section 9, timing control circuit 10, write control Since the circuit 11 and the average calculation section 12 have the same names as those shown in FIG. 3, their explanations will be omitted.

The rotation angle detection device 7 outputs as a first deviation angle θ how far the transducer 1 is deviated from a reference direction (for example, north of the earth's magnetic field). The transducer 1 detects the target by changing the angle by a predetermined angle δ.

[0014] The address control circuit 6 shifts the address A from the timing control circuit 10 corresponding to each detection direction of the transducer 1 by the first deviation angle θ to obtain a second deviation angle φ0,
An address N corresponding to φ1, .about., φn is created. In other words, the address N corresponds to the second deviation angle φ, which is the deviation of the detection direction from the reference direction. The address control circuit 6 outputs the created address N to the signal processing memories 4 and 5 in synchronization with the command R/W of the write control circuit 11.

When the address N is output, the echo data stored at the address N of the memory 4 is stored at the address N of the memory 5 replacing the previous echo data, while the received echo data is stored at the address N of the memory 4. Echo data from unit 3 is stored.

The average calculation unit 12 calculates the average value of the data stored at each same address in the memories 4 and 5, outputs it as a detected image signal, and displays the average value on a display (not shown) as a detected image. Although the present embodiment has been described using two memories, it is clear that more than two memories may be used. In addition, the data stored in memory 4 is transferred to memory 5 by cascading the memories 4 and 5, and new data is stored in memory 4 to update the data, but the new data is written to memories 4 and 5 alternately. It is clear that data may be updated by

[0017]

Effects of the Invention As explained above, the present invention sets addresses in each memory for each deviation from a predetermined direction, and converts detection data detected via a transducer into detection data for each deviation. By converting and storing cumulatively each transmission/reception timing, area averaging processing (average for each screen obtained from multiple transmission/reception cycles) can be performed even while the transducer is rotating. , target extraction, etc. can be used more freely.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a scanning sonar of the present invention.

FIG. 2 is a diagram showing first and second declination angles.

FIG. 3 is a block diagram showing a conventional example.

[Explanation of symbols]

1 Transducer/receiver 2 Switcher 3 Receiving section 4,5　　　　　　Signal processing memory 6 Address control circuit 7 Turning angle detection device 8 Swivel mechanism 9 Transmission section 10 Timing control circuit 11 Write control circuit 12 Average calculation section

Claims (1)

[Claims] Claim 1: In a scanning sonar that detects underwater using ultrasonic waves with substantially periodic transmission and reception timing by rotating a transducer, the orientation of the transducer with respect to a predetermined direction is used as a first declination angle. a turning angle detection device for detection, two or more memories for storing echo data to which addresses are assigned for each second polarization angle indicating deviation with respect to the predetermined direction, and the transducer at each transmission/reception timing. an address control unit that converts each detected direction into a second declination angle with reference to the first declination angle, and outputs an address of each memory corresponding to the converted second declination angle;
a data writing unit that updates the oldest echo data stored in the memory according to the address output by the address control unit using the echo data received by the transducer;
1. A scanning sonar comprising: an average calculation section that calculates the average value of echo data for each same address in each memory and outputs it as a detected image signal.