JP7219640B2 - Underwater detection device and underwater detection method - Google Patents

Description

The present invention relates to an underwater detection device and an underwater detection method for detecting underwater targets.

For example, U.S. Pat. No. 5,930,003 discloses a transducer that transmits an ultrasonic beam as a transmitted wave into water to scan an area in the water and generates a received signal from the received wave, including reflection of the transmitted wave on targets in the water. ing. Further, Patent Document 2 discloses an underwater detection device (sonar) that generates a video signal for displaying underwater information in a scan area as a video based on a received signal generated by a transducer.

In an underwater detection device using a transducer as disclosed in Patent Document 1 and an underwater detection device as disclosed in Patent Document 2, a video signal of an echo of an underwater target such as a school of fish is generated as underwater information. be. Based on this video signal, an echo of a target such as a school of fish is displayed as an image on a display unit such as a display.

Japanese Patent No. 4798826 Japanese Patent No. 5089319

Transducers and underwater sounders such as those disclosed in US Pat. When a transmitted wave is transmitted from a transducer mounted on a ship and a received wave reflected by a target is received, the frequency of the received wave differs from that of the transmitted wave according to the speed of the ship and the direction of arrival of the received wave. A shifting Doppler shift occurs. Therefore, in the underwater detection device, based on the amount of Doppler shift of the echo of the target, the received signal from the transducer is corrected to acquire the echo signal, and the video signal for displaying the echo on the display unit is generated. is done. This makes it possible to detect a target such as a school of fish whose ground speed is zero and display its echo.

Underwater detection devices such as those described above are also used on vessels engaged in trawl fishing. Vessel trawlers tow trawler gear including otter boards (trawl doors) and nets. Since the trawling gear is towed by a vessel, the ground speed is not zero, and it moves with the vessel at approximately the same speed as the vessel.

A target such as a school of fish whose ground speed is zero can be detected by correcting the Doppler shift as described above, and the echo of the target can be displayed. However, trawl gear with non-zero ground speed cannot be detected with correction for Doppler shift, so its echo cannot be displayed. Therefore, when trawling, the user of the underwater detection device must make a decision to catch the school of fish based only on the echo display of the detected school of fish without the trawl fishing gear being detected. Therefore, it is desirable to be able to detect both schools of fish and trawl gear and display their echoes on the display.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an underwater detection apparatus and an underwater detection method capable of detecting both schools of fish and trawl gear and displaying their echoes. That is.

(1) In order to solve the above problems, an underwater detection device according to one aspect of the present invention is an underwater detection device for use on a ship, comprising a transmission transducer for transmitting a transmission wave underwater, and an underwater target. a receiving transducer that receives a received wave including the reflection of the transmitted wave and generates a received signal from the received received wave; and a frequency shift amount that occurs when the frequency of the received wave shifts with respect to the frequency of the transmitted wave. and a first signal processing unit that obtains a first echo signal from the received signal based on the frequency shift amount, wherein the first echo signal is obtained from within a first direction range A first signal processing unit that acquires from the received signal corresponding to the received wave having an arrival azimuth angle, and a second signal processing unit that acquires a second echo signal from the received signal independently of the frequency shift amount. a second signal processing unit that acquires the second echo signal from the received signal corresponding to the received wave having an azimuth angle of arrival from within a second directional range different from the first directional range; and a video signal generation unit that generates an echo video signal for displaying the echo of the target on a display unit based on the first echo signal and the second echo signal.

(2) The first directional range may include the bow direction of the vessel, and the second directional range may include the stern direction of the vessel.

(3) The second signal processing unit changes a parameter for specifying the second direction range based on the change in the bow direction when the bow direction of the ship is changing. Direction range may change.

(4) When the bow direction of the ship is changing, the second signal processing unit adjusts the direction of a center line that bisects the second direction range into equal angle ranges based on the change in the bow direction. , the second directional range may be changed.

(5) The second signal processing unit rotates the direction of the center line that bisects the second direction range into equal angle ranges counterclockwise when the bow direction of the ship is changing clockwise. The change may change the second directional range.

(6) The second signal processing unit widens the angular range of the second direction range when the bow direction of the ship is changing than when the bow direction of the ship is not changing. , the second direction range may be changed.

(7) The angular range of the first directional range may be wider than the angular range of the second directional range.

(8) The first signal processing unit mixes the received signal with a local signal having a frequency adjusted based on the frequency shift amount, or the frequency characteristic is adjusted based on the frequency shift amount. The first echo signal may be acquired by filtering the received signal with a filter.

(9) The second signal processing unit mixes the received signal with a local signal having a fixed frequency set based on the frequency of the transmission wave, or sets the frequency characteristic based on the frequency of the transmission wave. The second echo signal may be obtained by filtering the received signal with a filter adjusted to .

(10) A data acquisition unit that acquires at least one of data on the speed of the ship and data on the warp length of the warp connected between the trawl fishing gear towed by the ship and the ship. , the second signal processing unit acquires the second echo signal by limiting the frequency band of the received signal, and the second signal processing unit obtains at least the ship speed data and the warp length data The frequency bands may be adjusted based on one.

(11) In the first state in which the boat speed is faster than in the second state, the frequency band may be narrower than in the second state.

(12) In the third state in which the warp length is shorter than in the fourth state, the frequency band may be narrower than in the fourth state.

(13) The video signal generation unit allocates a color different from a color allocated to the echo of the target to which the first echo signal corresponds to the echo of the target to which the second echo signal corresponds, so that the echo image is generated. may generate a signal.

(14) The second directional range may have a directional range that overlaps with the first directional range.

(15) A mark position setting unit that sets a position corresponding to an echo identified as an echo corresponding to at least part of the trawl fishing gear towed by the vessel as a mark setting position, which is a position where the mark of the trawl fishing gear is to be displayed. , wherein the video signal generator further generates a troll mark video signal for displaying the mark of the trawling gear at the mark setting position.

(16) When the mark position setting unit rotates the mark setting position around a rotation center position set at a position corresponding to the position of the ship when the bow direction of the ship is changing. There is

(17) The second signal processing section may acquire the second echo signal from the received signal corresponding to the received wave arriving within a predetermined distance range from the receiving transducer.

(18) The second signal processing section may acquire the second echo signal from the received signal corresponding to the received wave arriving from within a predetermined depth range in water.

(19) The first directional range may include the second directional range.

(20) Further, in order to solve the above problems, an underwater detection device according to one aspect of the present invention is an underwater detection device used in a vessel for trawl fishing, in which transmission waves are directed toward underwater trawl fishing gear. a receiving transducer that receives a received wave including the reflection of the transmitted wave from the trawling gear and generates a received signal from the received wave; and a signal that acquires an echo signal from the received signal. a processing unit, a video signal generating unit that generates an echo video signal based on the echo signal, and a position corresponding to the echo identified as the echo corresponding to at least a portion of the trawl gear by marking a mark on the trawl gear. a mark position setting unit for setting a mark setting position, which is a position to be displayed, wherein the video signal generating unit further generates a troll mark video signal for displaying the mark of the trawling gear at the mark setting position. The mark position setting unit rotates the mark setting position about a rotation center position set at a position corresponding to the position of the ship when the bow direction of the ship is changing.

(21) Further, in order to solve the above problems, an underwater detection method according to an aspect of the present invention transmits transmission waves underwater, receives reception waves including reflection of the transmission waves from an underwater target, generating a received signal from the received wave received; calculating a frequency shift amount caused by shifting the frequency of the received wave with respect to the frequency of the transmitted wave; and calculating a frequency shift amount from the received signal based on the frequency shift amount. obtaining one echo signal, obtaining the first echo signal from the received signal corresponding to the received wave having an azimuth angle of arrival from within a first directional range, and obtaining the received signal independently of the frequency shift amount; obtaining a second echo signal from the signal, obtaining the second echo signal from the received signal corresponding to the received wave having an azimuth of arrival from within a second range of directions different from the first range of directions; Based on the first echo signal and the second echo signal, an echo video signal is generated for displaying the echo of the target on a display unit.

According to the present invention, it is possible to provide an underwater detection device and an underwater detection method capable of detecting both schools of fish and trawl gear and displaying their echoes.

1 is a block diagram showing the configuration of an underwater detection device according to a first embodiment; FIG. FIG. 2 is a diagram schematically showing the state of a vessel for trawl fishing; FIG. 2 is a diagram schematically showing a transmission space in which transmission waves are transmitted by a transducer and a reception space in which reception waves are received by a transducer; 3 is a block diagram showing the configuration of a signal processor of the underwater detection device of the first embodiment; FIG. FIG. 4 is a diagram for explaining processing of the first signal processing section and the second signal processing section in the signal processor of the underwater detection device of the first embodiment; FIG. 7 is a diagram for explaining processing of a second signal processing section in the signal processor of the underwater detection device of the first embodiment; FIG. 7 is a diagram for explaining processing of a second signal processing section in the signal processor of the underwater detection device of the first embodiment; FIG. 7 is a diagram for explaining processing of a second signal processing section in the signal processor of the underwater detection device of the first embodiment; FIG. 4 is a diagram schematically showing an example of an image displayed on the display screen of the display unit; 4 is a flow chart for explaining the operation of the underwater detection device of the first embodiment; FIG. 10 is a diagram for explaining the first modification of the first embodiment, and is a diagram schematically showing an example of an image displayed on the display screen of the display unit; FIG. FIG. 10 is a diagram for explaining a second modification of the first embodiment, and is a diagram for explaining processing in the second modification of the first embodiment; FIG. FIG. 10 is a diagram for explaining the second modification of the first embodiment, and is a diagram schematically showing an example of an image displayed on the display screen of the display unit; FIG. FIG. 12 is a diagram for explaining a third modification of the first embodiment, and is a diagram for explaining processing in the third modification of the first embodiment; FIG. FIG. 10 is a diagram for explaining a comparative example of the third modification of the first embodiment, and is a diagram schematically showing an example of an image displayed on the display screen of the display unit; FIG. 10 is a diagram for explaining the third modification of the first embodiment, and is a diagram schematically showing an example of an image displayed on the display screen of the display unit; FIG. FIG. 10 is a diagram for explaining the third modification of the first embodiment, and is a diagram schematically showing an example of an image displayed on the display screen of the display unit; FIG. FIG. 12 is a diagram for explaining a fourth modification of the first embodiment, and is a diagram for explaining processing in the fourth modification of the first embodiment; FIG. FIG. 9 is a block diagram showing the configuration of a signal processor of the underwater detection device of the second embodiment; FIG. 10 is a diagram schematically showing an example of an image displayed on the display screen of the display unit based on the processing of the underwater detection device of the second embodiment; FIG. 10 is a diagram schematically showing an example of an image displayed on the display screen of the display unit based on the processing of the underwater detection device of the second embodiment; 22 is a diagram showing an enlarged part of an example of the video shown in FIG. 21; FIG. FIG. 10 is a diagram for explaining processing of a mark position setting unit in a signal processor of the underwater detection device of the second embodiment; FIG. 10 is a diagram for explaining processing of a mark position setting unit in a signal processor of the underwater detection device of the second embodiment; FIG. 10 is a diagram for explaining a modification of the second embodiment, and is a diagram for explaining processing in the modification of the second embodiment;

(First embodiment)
An underwater detection device 1 according to a first embodiment of the present invention will be described below with reference to the drawings.

[Overall configuration of underwater detection device and configuration of trawl fishing gear]
FIG. 1 is a block diagram showing the configuration of an underwater detection device 1 according to the first embodiment of the present invention. The underwater detection device 1 of the present embodiment is used, for example, in vessels such as fishing vessels, and more specifically in vessels for trawl fishing. FIG. 2 is a diagram schematically showing the state of a vessel S for trawl fishing. The underwater detection device 1 is used on a vessel S for trawl fishing.

As shown in FIG. 2, in trawl fishing, a trawl fishing gear 100 towed by a vessel S is used. The trawl fishing gear 100 includes an otter board 101, also called a trawl door, and a net 102 for catching a school of fish. The trawl fishing gear 100 towed by the ship S and the ship S are connected by a warp 103 .

The otter board 101 of the trawl fishing gear 100 is used to deploy the net opening 102 a of the net 102 . In addition, although FIG. 2 illustrates a form in which a pair of otter boards 101 are provided as the trawl fishing gear 100, this does not have to be the case. The trawl gear may be configured with three or more otter boards. For example, the trawl gear may be configured with three otter boards to deploy two net mouths.

Each of the pair of otter boards 101 is connected to the ship S at warp 103 . The warp 103 is paid out or wound up via a top roller (not shown) provided at the stern of the ship S. As shown in FIG. The warp length, which is the length of the warp 103 connected to the trawling fishing gear 100 and the vessel S between the trawl fishing gear 100 and the vessel S, is lengthened by the warp 103 being let out from the top roller, and is passed through the top roller. By being wound up, it becomes shorter. The warp length, which is the length of the warp 103 connected between the trawl fishing gear 100 and the ship S, is the length of the portion of the warp 103 between the otter board 101 and the top roller provided at the stern of the ship S. and is measured based on, for example, the number of revolutions of the top roller.

The otter board 101 and the net 102 are connected by wires 104 . A plurality of floats 105 are provided at the net mouth 102 a of the net 102 . The trawling gear 100 may include the otter board 101 and the net 102 , but may include the wire 104 and the float 105 in addition to the otter board 101 and net 102 .

An underwater detection device 1 of the first embodiment used on a vessel S for trawl fishing comprises a scanning sonar 10 and a signal processor 4, as shown in FIG. The underwater detection device 1 has a configuration in which, for example, a signal processor 4 is externally attached to a generally known scanning sonar 10 . The underwater detection device 1 may have a configuration in which the signal processor 4 is mounted on the scanning sonar 10 instead of being externally attached to the scanning sonar 10 . Further, the underwater detection device 1 is externally provided with a display unit 5 configured as a display device such as a display. The display unit 5 is connected to the signal processor 4 .

A scanning sonar 10 includes a transducer 2 and a transmitter/receiver 3 .

[Configuration of transducer]
The transducer 2 has a function of transmitting and receiving ultrasonic waves, and is attached to the bottom of the ship S. For example, as an example, the transducer 2 is formed in a substantially spherical shape.

Specifically, the transducer 2 has a substantially spherical housing and ultrasonic transducers (not shown) as a plurality of transducer elements attached to the outer peripheral surface of the housing. The ultrasonic transducer transmits ultrasonic waves to an underwater transmission space as transmitted waves, receives received waves as reflected waves including the reflection of the transmitted waves from targets in the water, and converts the received waves into electrical signals. By doing so, a received signal is generated from the received wave and output to the transmitter/receiver 3 . That is, the transducer 2 is configured as a transmitting transducer for transmitting transmission waves underwater, receives reception waves including the reflection of the transmission waves at an underwater target, and generates a reception signal from the received reception waves. It is configured as a receiving transducer that Targets in the water to which the transmission waves transmitted from the transducer 2 are reflected include schools of fish, trawl fishing gear 100, and the like.

In this embodiment, the transducer 2 has a spherical case, but the shape is not particularly limited, and other shapes such as a substantially cylindrical shape may be used. good too. When the housing of the transducer 2 has a substantially cylindrical shape, the transducer 2 is arranged so that its axial direction is along the vertical direction and its radial direction is along the horizontal direction.

FIG. 3 is a diagram schematically showing a transmission space TS in which transmission waves are transmitted by the transducer 2 and a plurality of reception spaces RS in which reception waves are received by the transducer 2. As shown in FIG. The transmission waves transmitted from the transducer 2 mounted on the ship S are simultaneously transmitted from the transducer 2 in all directions in the water around the ship S, forming, for example, a hemispherical transmission beam. be done. When a hemispherical transmission beam is formed, the transmission space TS through which the transmission wave is transmitted is configured as a hemispherical space. The shape of the transmission beam is not limited to a hemispherical shape, and can be formed in various different shapes depending on the shape of the transducer 2 or the amplitude and phase of the electrical signal input to each transducer element of the transducer 2. be.

Further, after transmitting the transmission beam, the transducer 2 simultaneously forms a plurality of reception beams that scan in the circumferential direction (in the direction of the azimuth angle θ indicated by the arrow in FIG. 3) in the transmission space TS. That is, all reception beams are formed at one reception timing by the transducer 2 . A plurality of receiving spaces RS in which received waves reflected by targets such as schools of fish in water or trawl fishing gear 100 are arranged side by side along the circumferential direction of the transmitting space TS (that is, along the direction of the azimuth angle θ). (ie, each space in which the receive beams are formed).

[Structure of transceiver]
The transceiver 3 includes a transmission/reception switching section 3 a, a transmission circuit section 6 and a reception circuit section 7 .

The transmission/reception switching unit 3 a is for switching between transmission and reception of a signal to the transducer 2 . Specifically, when transmitting a drive signal for driving the transducer 2 to the transducer 2, the transmission/reception switching unit 3a outputs the drive signal output by the transmission circuit unit 6 to the transducer 2. . On the other hand, when receiving a reception signal from the transducer 2 , the transmission/reception switching unit 3 a outputs the reception signal received from the transducer 2 to the reception circuit unit 7 .

The transmission circuit section 6 generates a drive signal that is the basis of transmission waves transmitted from the transducer 2 . More specifically, the transmission circuit section 6 has a transmission circuit (not shown) provided corresponding to each ultrasonic transducer, and each transmission circuit generates a drive signal.

The receiving circuit section 7 has an analog section 7a and an A/D conversion section 7b. The analog unit 7a and the A/D conversion unit 7b are reception circuits provided corresponding to each ultrasonic transducer, and are reception circuits (not shown) that process reception signals generated from received reception waves. is configured with The analog section 7a amplifies the received signal as an electrical signal generated from the received wave by the transducer 2 and outputs the received signal, and limits the band of the received signal to remove unnecessary frequency components. The A/D conversion section 7b converts the received signal amplified by the analog section 7a into a received signal as a digital signal. Then, the receiving circuit section 7 outputs the received signal converted into a digital signal by the A/D converting section 7 b to the signal processor 4 .

[Display part configuration]
The display unit 5 is configured as a display device such as a display. Then, the display unit 5 displays an image corresponding to the image signal output from the signal processor 4 on the display screen. The display unit 5 displays, for example, a three-dimensional underwater state below the ship S as a bird's-eye view. As a result, the user of the underwater detection device 1 can see the display screen and see the state of the sea below the ship S (for example, the presence and position of structures such as schools of fish, trawl fishing gear 100, undulations of the seabed, and artificial reefs). ) can be inferred.

[Overall Configuration of Signal Processor]
FIG. 4 is a block diagram showing the configuration of the signal processor 4. As shown in FIG. 1 and 4, the signal processor 4 processes the received signal output from the receiving circuit unit 7 to generate a target echo signal and display the target echo on the display unit 5. processing to generate an echo video signal of the

The signal processor 4 includes a beam forming section 9, a data acquiring section 10, a Doppler shift calculating section 11, a first signal processing section 12, a second signal processing section 13, a video signal generating section 14, and the like.

The signal processor 4 is a device connected to the transmitter/receiver 3 of the scanning sonar 10 by a cable or the like, and is composed of, for example, a PC (personal computer). The signal processor 4 is composed of a hardware processor 8 (for example, CPU, FPGA, etc.) and devices such as non-volatile memory. The hardware processor 8 functions as a beam forming unit 9, a data acquisition unit 10, a Doppler shift calculation unit 11, a first signal processing unit 12, a second signal processing unit 13, and a video signal generation unit 14, which will be described in detail below. do. For example, when the CPU reads out and executes a program from the nonvolatile memory, the hardware processor 8 performs the beam forming unit 9, the data acquiring unit 10, the Doppler shift calculating unit 11, the first signal processing unit 12, the second signal It functions as a processing unit 13 and a video signal generation unit 14 .

[Configuration of Beam Forming Section]
The beam forming unit 9 is configured to perform beam forming processing (specifically, phasing addition) and filtering processing for each of the plurality of reception spatial RSs based on the received signal received from the receiving circuit unit 7. ing. In the beam forming process, the beam forming unit 9 generates a reception beam signal that is equivalent to a signal obtained by a single ultrasonic transducer having sharp directivity in a specific direction. Then, the beam forming unit 9 repeats this process while changing the combination of the ultrasonic transducers to be subjected to the beam forming process, thereby forming a large number of reception signals having directivity in each direction corresponding to each reception space RS. Generate a beam signal. Further, the beam forming unit 9 applies filter processing such as a band-limiting filter or a pulse compression filter to each reception beam formed corresponding to each reception space RS. Through these processes, the beam forming unit 9 generates received signals that have undergone beam forming and filtering.

[Configuration of data acquisition unit]
The data acquisition unit 10 acquires data on the bow direction of the ship S, data on the speed of the ship S, and data on the warp length of the warp 103 connected between the trawl fishing gear 100 towed by the ship S and the ship S. is configured as

The ship S is equipped with a gyro compass (not shown) or a satellite compass (not shown) that detects the bow direction of the ship S as an absolute azimuth. Incidentally, the satellite compass has, for example, two GPS antennas attached along a straight line parallel to the bow direction on the ship S, receives radio waves transmitted from the positioning satellites with the two GPS antennas, and receives The relative position between the two GPS antennas is measured based on the carrier phase of the radio signal obtained, and the bow direction of the ship S is detected as an absolute azimuth. A gyrocompass or satellite compass mounted on the ship S is connected to a signal processor 4, and configured to output to the signal processor 4 data on the bow direction of the ship S detected by the gyrocompass or satellite compass. It is

Further, the ship S is equipped with a speedometer (not shown) for measuring the speed of the ship S. As shown in FIG. The speedometer is, for example, a Doppler sonar that is attached to the bottom of a ship, transmits ultrasonic waves toward the seabed in multiple axial directions, and measures the Doppler frequency contained in the reflected waves to measure the speed of the ship. . A speedometer mounted on the ship S is connected to the signal processor 4 and configured to output speed data of the ship S detected by the speedometer to the signal processor 4 . The ship S may not be provided with a ship speed gauge as an independent device, and the ship speed may be measured by the transducer 2 .

A warp length measuring device (not shown) that measures the warp length of the warp 103 connected between the trawler fishing gear 100 towed by the ship S and the ship S is provided, for example, at the stern of the ship S to measure the warp 103. and an encoder for detecting the number of revolutions of the top roller that rotates during the winding operation. The warp length measuring device measures the warp length based on the rotation speed of the top roller detected by the encoder. The warp length measuring device is connected to the signal processor 4 and configured to output to the signal processor 4 the warp length data of the warp 103 measured by the warp length measuring device.

In this embodiment, the data acquisition unit 10 is configured to acquire both the speed data of the ship S and the warp length data of the warp 103, but this need not be the case. . For example, the data acquisition unit 10 may be configured to acquire at least one of the ship speed data of the ship S and the warp length data of the warp 103 .

[Configuration of Doppler shift calculator]
When a received wave is received by the transducer 2, the frequency of the received wave differs from the frequency of the transmitted wave transmitted from the transducer 2, depending on the speed of the ship S and the direction of arrival of the received wave. A shifting Doppler shift occurs. The Doppler shift calculator 11 calculates a frequency shift amount caused by shifting the frequency of the received wave with respect to the frequency of the transmitted wave.

The Doppler shift calculation unit 11 is based on the data of the heading direction and the data of the ship speed acquired by the data acquisition unit 10, and the received signal generated by the beam forming unit 9 and subjected to beam forming processing and filtering processing. , the amount of frequency shift is calculated for each reception space RS. More specifically, the Doppler shift calculator 11 calculates the frequency shift amount Δf by calculating the ship speed v of the ship S, the sound speed c, the frequency f0 of the transmission wave, and the arrival frequency of the received wave for which the frequency shift amount Δf is calculated. Using the azimuth angle θd, it is calculated by the following equation (1).
Δf=2×(v/c)×f0×cos θd (1)
The arrival azimuth angle θd of the received wave for which the frequency shift amount Δf is calculated is obtained as the angle formed by the azimuth direction of the reception space RS for which the frequency shift amount Δf is calculated with respect to the bow direction of the ship S. .

[Configuration of first signal processing unit and second signal processing unit]
Based on the frequency shift amount calculated by the Doppler shift calculation unit 11, the first signal processing unit 12 converts the received signal, which has undergone beam forming processing and the like in the beam forming unit 9, into a first echo as a target echo signal. configured to acquire a signal. The first signal processing unit 12 is configured to acquire the first echo signal from a received signal corresponding to a received wave having an arrival azimuth angle from within the predetermined first direction range R1. That is, the first signal processing unit 12 corrects the received signal corresponding to the received wave arriving from within the predetermined first direction range R1 based on the frequency shift amount calculated by the Doppler shift calculation unit 11, and corrects the received signal corresponding to the received wave. A first echo signal is acquired as an echo signal of a target existing within a first directional range R1 of . Further, the first signal processing unit 12 mixes the received signal, which has been subjected to beam forming processing and the like by the beam forming unit 9, with a local signal having a frequency adjusted based on the frequency shift amount, thereby forming a first echo. Get the signal. Alternatively, the first signal processing unit 12 performs filtering on the received signal that has undergone beam forming processing or the like in the beam forming unit 9 using a filter whose frequency characteristics are adjusted based on the frequency shift amount. Acquire the first echo signal.

The second signal processing unit 13 converts the received signal, which has undergone beam forming processing and the like in the beam forming unit 9, into a second signal as a target echo signal, independently of the frequency shift amount calculated by the Doppler shift calculating unit 11. It is configured to acquire two echo signals. Then, the second signal processing unit 13 converts the second echo signal to a received signal corresponding to a received wave having an arrival azimuth angle from within a predetermined second directional range R2 different from the first directional range R1. configured to retrieve from That is, the second signal processing unit 13 responds to received waves arriving from within the predetermined second directional range R2, regardless of the frequency shift amount calculated by the Doppler shift calculation unit 11. A second echo signal as an echo signal of a target existing within the second directional range R2 is acquired from the received signal. In addition, the second signal processing unit 13 mixes the received signal, which has undergone beamforming processing and the like in the beam forming unit 9, with a local signal having a fixed frequency set based on the frequency of the transmission wave, thereby Acquire 2 echo signals. Alternatively, the second signal processing unit 13 performs filtering on the received signal that has undergone beam forming processing or the like in the beam forming unit 9 using a filter whose frequency characteristics are adjusted based on the frequency of the transmission wave. , to obtain the second echo signal.

FIG. 5 is a diagram for explaining the processing of the first signal processing section 12 and the second signal processing section 13 in the signal processor 4. As shown in FIG. FIG. 5 is a plan view schematically showing the ship S and its surroundings, showing the first direction range R1 and the second direction range R1 set in the processing of the first signal processing section 12 and the second signal processing section 13. A range R2 is shown as a sample. FIG. 5 also schematically shows the detection area DR corresponding to the transmission space TS.

As shown in FIG. 5, in the first signal processing unit 12, the first directional range R1 in which the first echo signal is acquired is set as a directional range including the bow direction HD of the ship S. As shown in FIG. Also, the first directional range R1 is set, for example, as a directional range centered on the bow direction HD. More specifically, for example, the first directional range R1 is set to a directional range of ±100° to 170° centered on the heading direction HD. The angle range of the first direction range R1 is set as an angle range wider than the angle range of the second direction range R2.

Then, the first signal processing unit 12 acquires the first echo signal from the reception signals generated in each of the plurality of reception beams formed within the first directional range R1 set around the heading direction HD. Thereby, the first signal processing unit 12 acquires the first echo signal as the echo signal of the target existing within the first directional range R1 from the received signal corresponding to the received wave arriving from within the first directional range R1. do. Further, the first signal processing unit 12 corrects the received signal corresponding to the received wave arriving from within the first direction range R1 based on the frequency shift amount calculated by the Doppler shift calculation unit 11 as described above. , to acquire the first echo signal. Therefore, when there is a target of a school of fish whose ground speed is zero in the first direction range R1, the target of the school of fish is detected in the first signal processing unit 12, and an echo signal of the target of the school of fish is generated. A first echo signal is acquired.

Further, as shown in FIG. 5, in the second signal processing section 13, the second direction range R2 in which the second echo signal is acquired is set as a direction range including the stern direction TD of the ship S. As shown in FIG. Further, the second direction range R2 is set as a direction range centered on the stern direction TD, for example. More specifically, for example, the second directional range R2 is set to a directional range of ±10° to 80° centered on the stern direction TD. In this embodiment, the second directional range R2 is set so as to be adjacent to the first directional range R1 in the direction of the azimuth angle θ. That is, in the present embodiment, the boundary lines on both sides of the first directional range R1 in the azimuth angle θ direction match the boundary lines on both sides of the second directional range R2 in the azimuth angle θ direction. For example, the first direction range R1 is set to a direction range of ±140° centered on the bow direction HD, and the second direction range R2 is set to a direction range of ±40° centered on the stern direction TD. .

The second signal processing unit 13 acquires the second echo signal from the received signal generated in each of the plurality of receive beams formed within the second direction range R2 set around the stern direction TD. Thereby, the second signal processing unit 13 acquires the second echo signal as the echo signal of the target existing within the second directional range R2 from the received signal corresponding to the received wave arriving from within the second directional range R2. do. In addition, as described above, the second signal processing unit 13 is independent of the amount of frequency shift calculated by the Doppler shift calculation unit 11, and receives signals corresponding to received waves arriving from within the second directional range R2. A second echo signal is obtained from the signal. Further, within the second direction range R2, which is the direction range on the stern direction TD side of the ship S, there is a target as the trawl fishing gear 100 that moves at substantially the same speed as the speed of the ship S. Therefore, in the second signal processing unit 13, the target of the trawl fishing gear 100 existing within the second directional range R2 is detected, and the second echo signal as the echo signal of the target of the trawl fishing gear 100 is acquired.

Further, the second signal processing unit 13 filters the received signal using a filter whose frequency characteristics are adjusted based on the frequency of the transmitted wave. A second echo signal is obtained by limiting the frequency band. At this time, the second signal processing unit 13 adjusts the frequency band based on at least one of the speed data of the ship S and the warp length data of the warp 103 acquired by the data acquisition unit 10, for example. It is configured.

More specifically, when the second signal processing unit 13 adjusts the frequency band based on the speed data of the ship S, the speed of the ship S is equal to or higher than a predetermined speed in the first state. Sometimes, the frequency band is adjusted to be narrower than in the second state in which the speed of the ship S is less than the predetermined speed. Therefore, in the first state in which the speed of the ship S is faster than in the second state, the frequency band is narrower than in the second state. Further, when the second signal processing unit 13 adjusts the frequency band based on the warp length data of the warp 103, the warp length of the warp 103 is less than a predetermined length in the third state. The frequency band is adjusted to be narrower than in the fourth state in which the warp length of 103 is equal to or longer than a predetermined length. Therefore, in the third state in which the warp length is shorter than in the fourth state, the frequency band is narrower than in the fourth state.

When the speed of the ship S increases and when the warp length of the warp 103 decreases, the frequency of the received signal corresponding to the received wave reflected by the target as the trawl fishing gear 100 existing within the second direction range R2 less variation. On the other hand, when the speed of the ship S slows down and the warp length of the warp 103 increases, the frequency fluctuation of the received signal corresponding to the received wave reflected by the target as the trawl fishing gear 100 increases. Therefore, when the speed of the ship S is higher than a predetermined speed and when the warp length of the warp 103 is less than a predetermined length, the frequency band is narrowed so that the target of the trawl fishing gear 100 can be handled. When the frequency variation of the received signal is small, it is possible to acquire the second echo signal for displaying the echo of the trawl fishing gear 100 with improved contrast on the display unit 5 . On the other hand, when the speed of the ship S is less than the predetermined speed and when the warp length of the warp 103 is greater than or equal to the predetermined length, the frequency band is widened without being narrowed, so that the trawl fishing gear 100 When the frequency fluctuation of the received signal corresponding to the target is large, detection omission of the target as the trawl fishing gear 100 can be reduced. In this embodiment, the second signal processing unit 13 performs processing for adjusting the frequency band based on at least one of the ship speed data of the ship S and the warp length data of the warp 103. A form in which this processing is not performed may be implemented.

Further, the second signal processing unit 13 changes the parameter for specifying the second direction range R2 based on the change in the bow direction HD when the bow direction HD of the ship S is changing. Change the range R2. Various parameters can be selected as parameters that specify the second direction range R2 and are changed when the heading HD changes. A parameter of orientation or a parameter of magnitude of the angular range of the second directional range R2 can be selected. The second signal processing unit 13 of the present embodiment is configured to change, for example, the parameter of the direction of the center line that bisects the second direction range R2 into equal angular ranges when the heading HD changes. .

6, 7 and 8 are diagrams for explaining the processing of the second signal processing unit 13. FIG. 6, 7 and 8 schematically show the first directional range R1 and the second directional range R2 together with the detection area DR corresponding to the transmission space TS. Moreover, FIG. 6 illustrates the first direction range R1 and the second direction range R2 in a state in which the bow direction HD of the ship S does not change, and FIGS. The first directional range R1 and the second directional range R2 in a changing state are illustrated. 6, 7 and 8 also schematically show the wake WA of the ship S in order to show the change in the bow direction HD of the ship S. As shown in FIG.

When the heading HD of the ship S does not change, the second signal processing unit 13 does not change the direction of the center line that bisects the second direction range R2 into equal angle ranges, as shown in FIG. is configured to When the bow direction HD of the ship S does not change, the direction of the center line that bisects the second direction range R2 into equal angle ranges is parallel to the stern direction of the ship S.

On the other hand, when the heading HD of the ship S is changing, the second signal processing unit 13, as shown in FIGS. is configured to change the second direction range R2 by changing the orientation of based on the change in the heading direction HD. 7 and 8, the second direction range R2 when the heading direction HD changes is indicated by a solid double-ended arrow R2, and the boundary lines on both sides of the second direction range R2 when the heading direction HD changes are indicated by dashed lines. is shown. 7 and 8, the second direction range R2 before the change in the heading HD, in which the heading HD does not change, is indicated by a two-dot chain double-ended arrow R20. The boundary lines on both sides of the second direction range R2 are indicated by two-dot chain lines, and the center line of the second direction range R2 before the change in the heading direction HD is indicated by one-dot chain line CL0. As shown in FIGS. 7 and 8, when the heading HD changes, the second signal processing unit 13 changes the direction of the center line CL of the second direction range R2 based on the change in the heading HD. Change the bi-directional range R2.

Further, as shown in FIG. 7, the second signal processing unit 13 rotates the direction of the center line CL of the second direction range R2 counterclockwise when the bow direction HD of the ship S is changing clockwise. By changing, it is configured to change the second direction range R2. Furthermore, as shown in FIG. 8, the second signal processing unit 13 rotates the direction of the center line CL of the second direction range R2 clockwise when the bow direction HD of the ship S is changing counterclockwise. By changing, it is configured to change the second direction range R2. When the second signal processing unit 13 changes the second direction range R2 when the heading HD of the ship S changes, the first signal processing unit 12 changes the , the first directional range R1 is changed so that the first directional range R1 is always adjacent to the second directional range R2 in the direction of the azimuth angle θ.

As described above, when the heading HD of the ship S is changing, the second signal processing unit 13 changes the parameter for specifying the second direction range R2 based on the change in the heading HD. The second direction range R2 is changed. Thereby, the second directional range R2 can be changed so that the trawl fishing gear 100 whose position relative to the vessel S changes when the bow direction HD of the vessel S changes exists in the second directional range R2.

When the change in the bow direction HD of the ship S is completed, the second signal processing unit 13 adjusts the second direction range R2 so that the direction of the center line CL of the second direction range R2 is parallel to the stern direction TD. change (see Figure 6). That is, when the bow direction HD returns to the state where the bow direction HD has not changed, the second signal processing unit 13 returns the direction of the center line CL of the second direction range R2 to the direction parallel to the stern direction TD. Change the range R2.

[Configuration of video signal generator]
Based on the first echo signal and the second echo signal generated by the first signal processing unit 12 and the second signal processing unit 13, the video signal generation unit 14 generates an echo for displaying the echo of the target on the display unit 5. Generate a video signal. In addition, the video signal generation unit 14 performs, for example, isosurface processing (that is, surface rendering processing) or volume rendering processing to display targets corresponding to the first echo signal and the second echo signal as three-dimensional area images. to generate an echo video signal for display. Note that the 3D area image is an image that expresses the distribution of targets within a 3D area. The echo video signal generated by the video signal generating section 14 is output to the display section 5, and the echo of the target is displayed on the display screen of the display section 5. FIG. FIG. 9 is a diagram schematically showing an example of an image displayed on the display screen of the display unit 5. As shown in FIG. 9 illustrates a three-dimensional area image IM1 displayed on the display screen of the display unit 5 based on the echo image signal generated by the image signal generation unit 14. As shown in FIG.

As illustrated in FIG. 9, in the three-dimensional area image IM1 displayed on the display unit 5, echoes (E1, E2, E3, E4) of targets detected within the underwater detection area DR corresponding to the transmission space TS , E5, E6) are displayed. The three-dimensional area image IM1 displayed on the display unit 5 is displayed on the two-dimensional display screen of the display unit 5 in a projected state. In the display of the three-dimensional area image IM1, there are also equidistant lines HL1 and HL2 indicating equidistant positions on the water surface from the ship S, and isodepth lines VL1 and VL2 indicating the same depth position in the depth direction of the water. is also included. Although FIG. 9 exemplifies a mode in which lines indicating the detection area DR are also displayed in the three-dimensional area image IM1, the lines indicating the detection area DR may not be displayed.

The video signal generator 14 generates an echo video signal for displaying target echoes (E1, E2, E3) on the display 5 based on the first echo signal generated by the first signal processor 12. . Echoes (E1, E2, E3) are displayed based on an echo video signal generated from a first echo signal, which is an echo signal of a target as a school of fish existing within the first direction range R1 and having zero ground speed. be done. Therefore, the echoes (E1, E2, E3) display the echoes of the target as a school of fish.

Further, the video signal generator 14 generates an echo video signal for displaying the target echoes (E4, E5, E6) on the display 5 based on the second echo signal generated by the second signal processor 13. Generate. The echoes (E4, E5, E6) are echo images generated from the second echo signals of the target as the trawl fishing gear 100 existing within the second direction range R2 and moving at substantially the same speed as the ship S. Displayed based on the signal. Therefore, the echoes (E4, E5, E6) represent the echoes of the target as the trawl gear 100. FIG. In FIG. 9, the echoes (E4, E5, E6) of the trawl fishing gear 100 are the echoes (E4, E5) of the target of the otter board 101 and the echoes E6 of the wire 104 and the float 105 near the mouth 102a of the net 102. is displayed on the display unit 5 as an example.

In the three-dimensional area image IM1 illustrated in FIG. 9, areas corresponding to echo signals with high signal strength levels are indicated by areas with high-density dot hatching, and echo signals with medium signal strength levels are indicated by high-density dot hatching. Areas corresponding to signals are indicated by hatched areas, and areas corresponding to echo signals with low signal strength levels are indicated by areas hatched with sparse dots. The echo video signal generated by the video signal generation unit 14 contains information on the display color when displayed on the display unit 5 . In the display unit 5, a high echo intensity area hatched with high density dots, a medium echo intensity area hatched with oblique lines, and an area hatched with low density dots. is displayed in a color based on display color information included in the echo video signal. For example, on the display unit 5, high echo intensity areas are indicated in red, medium echo intensity areas are indicated in green, and low echo intensity areas are indicated in blue.

[Operation of Underwater Detector]
FIG. 10 is a flowchart for explaining the operation of the underwater detection device 1, and is a flowchart illustrating an example of the operation of the underwater detection device 1. FIG. In FIG. 10, a transmission wave is transmitted underwater from the transducer 2, a received wave including the reflection of the transmission wave is received by the transducer 2, and the above-described processing is performed by the underwater detection device 1, It shows the operation until the image of the echo of the target is displayed on the display unit 5 . After the image of the echo of the target is displayed on the display unit 5, when the transmission wave is transmitted from the transducer 2 into the water, the operation shown in the flowchart of FIG. 10 is performed again. Incidentally, as shown in FIG. 10, the underwater detection method of the present embodiment is carried out by operating the underwater detection device 1 .

In the operation of the underwater detection device 1, first, transmission waves are transmitted from the transducer 2 to the transmission space TS in the water. A transmission wave transmitted to the underwater transmission space TS is reflected by an underwater target and received by the transducer 2 . The transducer 2 receives a received wave including the reflection of the transmitted wave from an underwater target, and generates a received signal from the received received wave (step S101). After generating the received signal, the transducer 2 outputs the generated received signal to the transmitter/receiver 3 . In the transmitter/receiver 3 , the reception circuit section 7 amplifies the received signal to remove unnecessary frequency components, converts the signal into a digital signal, and outputs the digital signal to the signal processor 4 .

When the signal processor 4 receives the received signal from the transmitter/receiver 3, the beam forming unit 9 performs beam forming (S102). That is, the beam forming unit 9 performs beamforming processing for each of a plurality of reception space RSs based on the reception signal, thereby generating a large number of reception beam signals having directivity in each azimuth corresponding to each reception space RS. do. After the beam forming process in the beam forming unit 9 is completed, the Doppler shift calculating unit 11 calculates the frequency shift amount caused by the shift of the frequency of the received wave with respect to the frequency of the transmitted wave as the azimuth angle of arrival of the received wave. (step S103).

After the frequency shift amount is calculated, the first signal processing unit 12 acquires the first echo signal from the received signal based on the frequency shift amount (step S104). At this time, the first signal processing unit 12 acquires the first echo signal from the received signal corresponding to the received wave having the arrival azimuth angle from the predetermined first direction range R1. Then, in the second signal processing unit 13, the second echo signal is acquired from the received signal independently of the frequency shift amount (step S105). At this time, the second signal processing unit 13 acquires the second echo signal from the received signal corresponding to the received wave having the azimuth angle of arrival from within a predetermined second directional range R2 different from the first directional range R1. .

After the first echo signal and the second echo signal are acquired by the first signal processing unit 12 and the second signal processing unit 13, the video signal generation unit 14 generates the first echo signal and the second echo signal. Based on this, an echo video signal is generated for displaying the echo of the target on the display unit 5 (step S106). Then, the echo video signal generated by the video signal generation unit 14 is output to the display unit 5 (step S107). The display unit 5 displays an echo image of the target as shown in FIG. 9 based on the input echo image signal. As a result, on the display unit 5, the target echoes (E1, E2, E3) as the school of fish detected within the first direction range R1 and the trawl fishing gear 100 detected within the second direction range R2 are displayed. target echoes (E4, E5, E6) are displayed. When the echo of the target is displayed on the display unit 5, the operation of the underwater detection device 1 shown in FIG. 10 temporarily ends. Once the operation shown in FIG. 10 of the underwater detection device 1 is finished, a transmission wave is transmitted from the transducer 2 to the underwater transmission space TS, and the operation shown in FIG. 10 is started again.

[effect]
According to this embodiment, the first echo signal is acquired from the received signal corresponding to the received wave having the azimuth angle of arrival from within the first direction range R1 based on the frequency shift amount. Therefore, when a target of a school of fish whose ground speed is zero exists within the first direction range R1, the target of the school of fish is detected and a first echo signal is acquired as an echo signal of the target of the school of fish. . Furthermore, according to the present embodiment, the second echo signal is obtained from the received signal corresponding to the received wave having the azimuth angle of arrival from within the second directional range R2 different from the first directional range R1, independently of the frequency shift amount. is obtained. Therefore, the target of the trawl fishing gear 100 existing within the second directional range R2 is detected, and the second echo signal as the echo signal of the target of the trawl fishing gear 100 is acquired. According to the present embodiment, echoes of the target of the shoal of fish and the trawl fishing gear 100 are displayed on the display unit 5 based on the first echo signal corresponding to the echo of the shoal of fish and the second echo signal corresponding to the trawl fishing gear 100. is generated, and echoes of the school of fish and the trawl fishing gear 100 are displayed on the display unit 5 based on the echo image signal.

Therefore, according to this embodiment, it is possible to provide an underwater detection device and an underwater detection method that can detect both a school of fish and trawl gear and display their echoes.

Further, according to the present embodiment, the first directional range R1 includes the bow direction of the ship S, and the second directional range R2 includes the stern direction of the ship S. Therefore, it is possible to more reliably detect a school of fish existing in the direction in which the vessel S for trawl fishing is advancing, and furthermore, it is possible to more reliably detect the trawl fishing gear 100 existing in the stern direction of the vessel S.

Further, according to the present embodiment, the second signal processing unit 13 changes the parameter specifying the second direction range R2 based on the change in the heading HD of the ship S when the heading HD is changing. Thus, the second direction range R2 is changed. Thereby, the second directional range R2 can be changed so that the trawl fishing gear 100 whose position relative to the vessel S changes when the bow direction HD of the vessel S changes exists in the second directional range R2.

Further, according to the present embodiment, the second signal processing unit 13 changes the direction of the center line that bisects the second direction range R2 into equal angle ranges in the direction of the bow HD when the direction of the bow HD is changing. By changing based on the change, the second directional range R2 is changed. Therefore, when the bow direction HD changes, the direction of the center line of the second direction range R2 can be easily directed to the area where the trawl fishing gear 100 is likely to exist. As a result, the second directional range R2 can be changed so that the trawl fishing gear 100 is more stably present in the second directional range R2.

Further, according to the present embodiment, the second signal processing unit 13 changes the direction of the center line of the second direction range R2 counterclockwise when the bow direction HD changes clockwise, and changes the direction of the center line of the second direction range R2 counterclockwise. When the clockwise direction is changed, the direction of the center line of the second directional range R2 is changed clockwise to change the second directional range R2. Therefore, when the bow direction HD changes, the direction of the center line of the second direction range R2 can be easily directed to the area where the trawling gear 100 is likely to exist according to the change direction of the bow direction HD. can. As a result, the second directional range R2 can be changed so that the trawl fishing gear 100 is more stably present in the second directional range R2.

Further, according to the present embodiment, the angle range of the first direction range R1 is set wider than the angle range of the second direction range R2. Therefore, the second directional range can be set according to the area where the trawling gear 100 exists, and the first directional range R1 can be set so that the school of fish can be detected in a wider area.

Further, according to the present embodiment, the second signal processing unit 13 adjusts the frequency band of the received signal based on the speed data of the ship S and the warp length data of the warp 103 . When the speed of the ship S is in a first state in which the speed of the ship S is equal to or higher than a predetermined speed, the second signal processing unit 13 is set in a second state in which the speed of the ship S is less than the predetermined speed Adjust to narrow the frequency band. That is, in the first state in which the speed of the ship S is faster than in the second state, the frequency band is narrower than in the second state. Further, the second signal processing unit 13 controls the warp length of the warp 103 in a third state in which the warp length is less than the predetermined length and in the fourth state in which the warp length of the warp 103 is equal to or greater than the predetermined length. Adjust to narrow the frequency band. That is, the frequency band is narrower in the third state than in the fourth state, where the warp length is shorter than in the fourth state. Therefore, when the speed of the ship S is higher than a predetermined speed and when the warp length of the warp 103 is less than a predetermined length, the frequency band is narrowed so that the target of the trawl fishing gear 100 can be handled. When the frequency variation of the received signal is small, it is possible to acquire the second echo signal for displaying the echo of the trawl fishing gear 100 with improved contrast on the display unit 5 . On the other hand, when the speed of the ship S is less than the predetermined speed and when the warp length of the warp 103 is greater than or equal to the predetermined length, the frequency band is widened without being narrowed, so that the trawl fishing gear 100 When the frequency fluctuation of the received signal corresponding to the target is large, detection omission of the target as the trawl fishing gear 100 can be reduced.

(First Modification of First Embodiment)
FIG. 11 is a diagram for explaining the first modification of the first embodiment, and is a diagram schematically showing an example of an image displayed on the display screen of the display unit 5. As shown in FIG. In the following description, points different from the above-described first embodiment will be described, and configurations similar or corresponding to those of the first embodiment are denoted by the same reference numerals in the drawings, or By quoting, overlapping descriptions are omitted as appropriate.

In the first embodiment, target echoes (E1, E2, E3) generated based on the first echo signal and target echoes (E4, E5, E6) generated based on the second echo signal are , are displayed in similar display colors depending on the signal strength level. On the other hand, in the first modification of the first embodiment, the target echoes (E1, E2, E3) displayed based on the echo video signal generated from the first echo signal and the echoes generated from the second echo signal The target echoes (E4, E5, E6) displayed based on the echo video signal obtained are displayed in different display colors.

As a specific configuration, in the first modification of the first embodiment, the video signal generation unit 14 assigns colors different from the colors assigned to the target echoes (E1, E2, E3) corresponding to the first echo signals. , the second echo signals are assigned to corresponding target echoes (E4, E5, E6) to generate echo image signals. That is, an echo video signal corresponding to a first echo signal for displaying echoes (E1, E2, E3) and an echo video signal corresponding to a second echo signal for displaying echoes (E4, E5, E6). contains information on different colors as information on display colors when displayed on the display unit 5 . Then, on the display unit 5, the image of the echo is displayed in a color based on the display color information contained in the echo image signal.

In the display example of the display screen of the display unit 5 illustrated in FIG. 11, the echoes (E1, E2, E3) corresponding to the first echo signal are the high-density dot hatching area, the oblique hatching area, and low density dot hatched areas, and the echoes (E4, E5, E6) to which the second echo signal corresponds are indicated by the shaded hatched areas. For example, in the display unit 5, the background color of the display screen is set to black, high-density dot hatching areas are indicated in red, oblique hatching areas are indicated in green, and low-density dot hatching is indicated in blue. , and shaded hatched areas are shown in white.

According to the first modification of the first embodiment, the target echoes (E1, E2, E3) generated based on the first echo signal and the target echoes (E4, E4, E3) generated based on the second echo signal E5, E6) can be displayed in different display colors. Therefore, the user can more easily distinguish between the echo of the school of fish and the echo of the trawl fishing gear 100 .

(Second Modification of First Embodiment)
FIG. 12 is a diagram for explaining a second modification of the first embodiment, and is a diagram for explaining processing in the second modification of the first embodiment. In the following description, points different from the above-described first embodiment will be described, and configurations similar or corresponding to those of the first embodiment are denoted by the same reference numerals in the drawings, or By quoting, overlapping descriptions are omitted as appropriate.

FIG. 12 is a diagram for explaining processing of the first signal processing unit 12 in the second modification of the first embodiment. Also, FIG. 12 is a plan view schematically showing the ship S and its surroundings, showing the first direction range R1 and the second direction range R1 set in the processing of the first signal processing unit 12 and the second signal processing unit 13. A range R2 is shown as a sample.

As shown in FIG. 12, in the second modification of the first embodiment, the first signal processing unit 12 sets the first direction range R1 in which the first echo signals are acquired to a direction including the bow direction HD of the ship S. It is set as a range, and is set within a range of ±180° centered on the heading direction HD. That is, in the second modification of the first embodiment, the first signal processing unit 12 sets the first directional range R1 in which the first echo signal is acquired as the directional range covering the entire circumference in the azimuth angle θ direction. . Therefore, the second directional range R2 set by the second signal processing unit 13 as a directional range including the stern direction TD of the ship S has a directional range that overlaps with the first directional range R1. , the second directional range R2 is entirely included in the first directional range R1.

In the second modification of the first embodiment, since the first directional range R1 is set as described above, the first echo signal corresponds to the received waves arriving from the directional range covering the entire circumference in the azimuth angle θ direction. obtained from the received signal. Therefore, the target of the school of fish whose ground speed is zero is detected in the direction range covering the entire circumference in the direction of the azimuth angle θ. On the other hand, the second directional range R2 is set in the same manner as in the first embodiment. Two echo signals are acquired.

FIG. 13 is a diagram for explaining the second modification of the first embodiment, and is a diagram schematically showing an example of an image displayed on the display screen of the display unit 5. As shown in FIG. In the display example of the display screen of the display unit 5 illustrated in FIG. 13, echoes (E1, E2, E3, E7) are displayed as echoes of the target to which the first echo signal corresponds, and the second echo signal corresponds. Echoes (E4, E5, E6) are displayed as echoes of the target. In the second modification of the first embodiment, as in the first modification of the first embodiment, the video signal generator 14 generates echoes (E1, E2, E3, E7) of the target to which the first echo signals correspond. are assigned to the echoes (E4, E5, E6) of the target to which the second echo signals correspond to generate echo video signals. That is, an echo video signal corresponding to a first echo signal for displaying echoes (E1, E2, E3, E7) and an echo corresponding to a second echo signal for displaying echoes (E4, E5, E6). The video signal includes information of different colors as information of display colors when displayed on the display unit 5 . Then, on the display unit 5, the image of the echo is displayed in a color based on the display color information contained in the echo image signal.

In the display example of the display screen of the display unit 5 illustrated in FIG. 13, the echoes (E1, E2, E3, and E7) corresponding to the first echo signal are in the high-density dot hatching area and the oblique hatching area. , and areas with sparse dot hatching, and the echoes (E4, E5, E6) to which the second echo signal corresponds are indicated with hatched areas. For example, in the display unit 5, the background color of the display screen is set to black, high-density dot hatching areas are indicated in red, oblique hatching areas are indicated in green, and low-density dot hatching is indicated in blue. , and shaded hatched areas are shown in white.

According to the second modification of the first embodiment, since the first directional range R1 and the second directional range R2 have overlapping directional ranges, even in the area for detecting the trawl fishing gear 100, a school of fish can be detected. detectable. That is, in the same directional range, the trawl fishing gear 100 and the school of fish can be detected at the same timing.

Further, according to the second modification of the first embodiment, even when the first directional range R1 and the second directional range R2 overlap, the echo of the target generated based on the first echo signal ( E1, E2, E3, E7) and target echoes (E4, E5, E6) generated based on the second echo signal can be displayed in different display colors. Therefore, even when the first directional range R1 and the second directional range R2 overlap, the user can easily distinguish between the echo of the school of fish and the echo of the trawl fishing gear 100. FIG.

(Third modification of the first embodiment)
FIG. 14 is a diagram for explaining the third modification of the first embodiment, and is a diagram for explaining processing in the third modification of the first embodiment. In the following description, points different from the above-described first embodiment will be described, and configurations similar or corresponding to those of the first embodiment are denoted by the same reference numerals in the drawings, or By quoting, overlapping descriptions are omitted as appropriate.

FIG. 14 is a diagram for explaining processing of the first signal processing unit 12 and the second signal processing unit 13 in the third modification of the first embodiment. FIG. 14 is a plan view schematically showing the ship S and its surroundings, in which the first direction range R1 and the second direction A range R2 and a second echo signal acquisition region RX, which is a range in which the acquisition of the second echo signal is performed, are schematically shown.

As shown in FIG. 14, in the third modification of the first embodiment, the first signal processing unit 12 sets the first direction range R1 in which the first echo signals are acquired to a direction including the bow direction HD of the ship S. It is set as a range, and is set within a range of ±180° centered on the heading direction HD. That is, in the third modification of the first embodiment, the first signal processing unit 12 sets the first directional range R1 in which the first echo signal is acquired as a directional range covering the entire circumference in the azimuth angle θ direction. . Therefore, the second directional range R2 set by the second signal processing unit 13 as a directional range including the stern direction TD of the ship S has a directional range that overlaps with the first directional range R1. In this modification, the first directional range R1 includes the second directional range R2, and includes the entire range of the second directional range R2.

In the third modification of the first embodiment, the first direction range R1 is set as described above. Therefore, the first signal processing unit 12 acquires the first echo signal from the received signal corresponding to the received wave arriving from the direction range over the entire circumference in the direction of the azimuth angle θ. As a result, the target of the school of fish whose ground speed is zero is detected in the direction range over the entire circumference in the direction of the azimuth angle θ.

Also, the second directional range R2 is set in the same manner as in the first embodiment. However, in the third modification of the first embodiment, the second signal processing unit 13 converts the second echo signal corresponding to the trawl fishing gear 100 to the second echo, which is a further restricted area within the second directional range R2. Acquired from the received signal corresponding to the received wave arriving from within the signal acquisition area RX. The second echo signal acquisition area RX is an area within the second direction range R2 and is configured as an area within a predetermined distance range DX away from the transducer 2 as a receiving transducer. The predetermined distance range DX away from the transducer 2 is configured as a distance range in which the distance from the transducer 2 is equal to or greater than a predetermined minimum distance D1 and equal to or less than a predetermined maximum distance D2. In FIG. 14, the positions at which the distance from the transducer 2 is the minimum distance D1 and the maximum distance D2 are indicated by dashed lines. Therefore, in the schematic plan view shown in FIG. 14, the second echo signal acquisition region RX has a dashed line indicating the minimum distance D1, a dashed line indicating the maximum distance D2, and boundary lines on both sides of the second direction range R2. The area surrounded by the dashed lines shown.

As described above, in the third modification of the first embodiment, the second signal processing unit 13 acquires the second echo signal from the received signal corresponding to the received wave arriving from within the second echo signal acquisition region RX. do. That is, the second signal processing unit 13 converts the second echo signal into a received signal corresponding to a received wave having an arrival azimuth angle from within the second direction range R2 and having a distance from the wave transducer 2 as a receiving transducer. It is acquired from a received signal corresponding to a received wave arriving from within a distant predetermined distance range DX.

The predetermined distance range DX that defines the second echo signal acquisition area RX may be set in advance, or may be set based on the operation of the underwater detection device 1 by the user. When the minimum distance is set based on the operation of the user of the underwater detection device 1, for example, the minimum distance is set by the user appropriately operating an operating device (not shown) such as a keyboard or pointing device of the underwater detection device 1. D1 and maximum distance D2 are set, thereby setting a predetermined distance range DX. Alternatively, the user's operation sets the median distance and the width of the distance that define the predetermined distance range DX, thereby setting the predetermined distance range DX. In this case, the median distance is set, for example, as an intermediate value between the minimum distance D1 and the maximum distance D2 (that is, a value obtained by dividing the sum of the minimum distance D1 and the maximum distance D2 by 2). The width of the distance is set, for example, as the value of the difference between the maximum distance D2 and the minimum distance D1. Alternatively, of the distance median and the distance width that define the predetermined distance range DX, only the distance width is set by the user's operation, and the distance median is the warp length data of the warp 103. may be set based on In this case, the median distance may be set as a constant multiple of the warp length based on the warp length data acquired by the data acquisition unit 10, for example.

FIG. 15 is a diagram for explaining a comparative example of the third modification of the first embodiment, and is a diagram schematically showing an example of an image displayed on the display screen of the display unit 5. As shown in FIG. FIG. 16 is a diagram for explaining the third modification of the first embodiment, and is a diagram schematically showing an example of an image displayed on the display screen of the display unit 5. As shown in FIG. 15 and 16, a three-dimensional area image IM2 viewed from above the ship S is displayed on the display unit 5 based on the echo image signal generated by the image signal generation unit 14. The form displayed on the display part 5 is illustrated. The three-dimensional area image IM2 is displayed as an image viewed from a vertical viewpoint, which is a viewpoint for viewing the detection area DR in the vertical direction from above the ship S.

In the display example as a comparative example of the third modified example of the first embodiment shown in FIG. , echoes (E1, E2, E3) are displayed, and in the second direction range R2, echoes (E4, E5) are displayed as the target echoes corresponding to the second echo signals. Therefore, in this comparative example, the user can visually recognize the echoes of the school of fish in the first directional range R1 except for the second directional range R2. You can see the echo. However, in this comparative example, the user cannot visually recognize the echo of the fish school in the area of the second directional range R2.

On the other hand, in the display example of the third modification of the first embodiment shown in FIG. 16, echoes (E1, E2, E3, E7, E8) are displayed as target echoes corresponding to the first echo signal. Echoes (E4, E5) are displayed as echoes of the target to which the two echo signals correspond. In the third modification of the first embodiment, the video signal generation unit 14 generates the first echo signal in the region other than the second echo signal acquisition region RX in the region of the first direction range R1 including the second direction range R2. , an echo video signal is generated for displaying the echo of the target on the display unit 5 . Further, the video signal generation unit 14 generates an echo video signal for displaying the echo of the target on the display unit 5 based on the second echo signal for the second echo signal acquisition region RX in the second direction range R2. do. Then, on the display unit 5, an echo image is displayed based on the echo image signal generated by the image signal generation unit 14. FIG. Therefore, as shown in FIG. 16, in the third modification of the first embodiment, echoes (E4, E5) of the trawl fishing gear 100 are displayed in the second echo signal acquisition area RX on the display screen of the display unit 5. be. In areas other than the second echo signal acquisition area RX, the echoes (E1, E2, E3, E7, E8) of the school of fish are displayed. Therefore, in the third modification of the first embodiment, the echoes (E4, E5) of the trawl fishing gear 100 are displayed in the second echo signal acquisition area RX in the area of the second direction range R2, and the second echo signal acquisition is performed. Echoes of fish schools (E7, E8) are displayed in areas other than the area RX. In the display example shown in FIG. 16, target echoes (E1, E2, E3, E7, E8) generated based on the first echo signal and target echoes (E1, E2, E3, E7, E8) generated based on the second echo signal ( E4, E5) are displayed in similar display colors according to the signal strength level.

According to the third modification of the first embodiment, the echoes (E4, E5) of the trawl fishing gear 100 are displayed in a narrow area of only the second echo signal acquisition area RX. That is, the echoes (E4, E5) of the trawl fishing gear 100 are displayed only in the second echo signal acquisition area RX, which is further limited within the predetermined distance range DX within the second directional range R2. On the other hand, for the echoes (E1, E2, E3, E7, E8) of the school of fish, in addition to the area other than the second directional range R2 in the first directional range R1, the second echo signal acquisition area in the second directional range R2 It is also displayed in areas other than RX. Therefore, according to the third modification of the first embodiment, it is possible to limit the area for displaying the echoes of the trawl fishing gear 100 to a narrower area around the trawl fishing gear 100 and display the echoes of the fish school in a wider area. can. Further, the area where the echoes of the trawl fishing gear 100 are displayed and the area where the echoes of the school of fish are displayed are distinguished by the second echo signal acquisition area RX and areas other than the second echo signal acquisition area RX. Therefore, the echoes of the trawl fishing gear 100 and the echoes of the school of fish can be displayed in the same display color, and the trouble of setting the display colors can be reduced.

Further, in the third modification of the first embodiment, as the display form of the video displayed on the display screen of the display unit 5, in addition to the display form shown in FIG. 16, other display forms can be implemented. FIG. 17 is a diagram for explaining the third modification of the first embodiment, and is a diagram schematically showing an example of an image displayed on the display screen of the display unit 5. The table shown in FIG. FIG. 10 is a diagram showing another display example different from the example shown; In FIG. 17, the three-dimensional area image displayed on the display unit 5 based on the echo image signal generated by the image signal generation unit 14 is a vertical viewpoint from above the ship S, as in the display example of FIG. 2 illustrates a form in which a three-dimensional area image IM2 of the detection area DR is displayed on the display unit 5. FIG.

In still another display example of the third modification of the first embodiment shown in FIG. 17, echoes (E1, E2, E3, E7, E8, E9) are displayed as echoes of the target to which the first echo signal corresponds. , and echoes (E4, E5) are displayed as echoes of the target to which the second echo signal corresponds. In the third modified example of the first embodiment whose display example is shown in FIG. 17, the video signal generator 14, based on the first echo signal, for the region of the first directional range R1 including the second directional range R2, An echo video signal for displaying the target echo on the display unit 5 is generated. Further, the video signal generation unit 14 generates an echo video signal for displaying the echo of the target on the display unit 5 based on the second echo signal for the second echo signal acquisition region RX in the second direction range R2. do.

In addition, the video signal generator 14 assigns a color different from the colors assigned to the echoes (E1, E2, E3, E7, E8, E9) of the target corresponding to the first echo signal to the target corresponding to the second echo signal. are assigned to the echoes (E4, E5) of , and an echo video signal is generated. That is, the echo video signal corresponds to the first echo signal for displaying the echoes (E1, E2, E3, E7, E8, E9) and the second echo signal for displaying the echoes (E4, E5). The echo video signal contains information of a different color as information of the display color when displayed on the display unit 5 . Then, on the display unit 5, the image of the echo is displayed in a color based on the display color information contained in the echo image signal.

17, the echoes (E1, E2, E3, E7, E8, and E9) corresponding to the first echo signal are shown in the high-density dot hatching area The echoes (E4, E5) to which the second echo signal corresponds are indicated by the shaded hatched areas and the sparsely hatched areas. For example, in the display unit 5, the background color of the display screen is set to black, the high density dot hatching area is indicated in red, the oblique hatching area is indicated in green, and the low density dot hatching area is indicated in green. Shown in blue, shaded hatched areas are shown in white.

In the display example shown in FIG. 17 of the third modification of the first embodiment, the echo image is displayed on the display unit 5 based on the echo image signal generated by the image signal generation unit 14 as described above. be. Therefore, as shown in FIG. 17, on the display screen of the display unit 5, echoes (E1, E2, E3, E7, E8, E9 ) is displayed. In the second echo signal acquisition region RX, the echoes (E4, E5) of the trawl fishing gear 100 are displayed in a display color different from the display color of the echoes (E1, E2, E3, E7, E8, E9) of the school of fish. be done. Therefore, in the display example shown in FIG. 17 of the third modified example of the first embodiment, in the second echo signal acquisition region RX within the second direction range R2, the echoes (E4, E5) of the trawl fishing gear 100 and the fish school can be displayed, and the echoes (E4, E5) of the trawl fishing gear 100 can be displayed in a display color different from the echoes of the school of fish (E1, E2, E3, E7, E8, E9). This allows the user to easily distinguish between the echo of the school of fish and the echo of the trawl fishing gear 100 .

In the third modified example of the first embodiment, as described above, the second signal processing unit 13 causes the second echo signal to be further limited within the predetermined distance range DX within the second direction range R2. Acquired from the received signal corresponding to the received wave arriving from within the echo signal acquisition area RX. However, not limited to this example, in the third modification of the first embodiment, the second signal processing unit 13 limits the second echo signal to within the predetermined distance range DX within the second direction range R2. Yet another variant may be implemented that acquires from received signals corresponding to received waves arriving from within a second echo signal acquisition region RX that is located in the second echo signal acquisition region RX and is also restricted to within a predetermined depth range in water. In this modification, the second echo signal acquisition area RX is an area within the second direction range R2, and is an area within a predetermined distance range DX away from the transducer 2 as a receiving transducer, Further, it is configured as a region within a predetermined depth range in water. The predetermined depth range in water is configured as a depth range in which the depth in water is deeper than a predetermined first depth and shallower than a predetermined second depth that is deeper than the first depth. be done.

As described above, in still another modification of the third modification of the first embodiment, the second signal processing unit 13 divides the second echo signal into the predetermined distance range DX within the second direction range R2. Acquired from the received signal corresponding to the received wave arriving from within the second echo signal acquisition area RX, which is an area limited both in terms of the predetermined depth range. That is, the second signal processing unit 13 converts the second echo signal into a received signal corresponding to a received wave having an arrival azimuth angle from within the second direction range R2 and having a distance from the wave transducer 2 as a receiving transducer. It is obtained from a received signal corresponding to a received wave that arrives from within a predetermined distance range DX and that arrives from within a predetermined depth range in water.

Note that in still another modification of the third modification of the first embodiment, the video signal generator 14 generates the first echo signal and the second echo signal in the same manner as in the third modification of the first embodiment. Based on this, an echo video signal is generated. Then, on the display unit 5, an echo image is displayed based on the echo image signal generated by the image signal generation unit 14. FIG.

According to still another modification of the third modification of the first embodiment, the echoes of the trawl fishing gear 100 are limited in both the predetermined distance range DX and the predetermined depth range within the second direction range R2. are displayed only in the second echo signal acquisition region RX. Therefore, according to still another modification of the third modification of the first embodiment, the area for displaying the echoes of the trawl fishing gear 100 is limited to a narrower area around the trawl fishing gear 100, and the echoes of the school of fish are displayed in a wider area. area can be displayed.

(Fourth modification of the first embodiment)
FIG. 18 is a diagram for explaining a fourth modification of the first embodiment, and is a diagram for explaining processing in the fourth modification of the first embodiment. In the following description, points different from the above-described first embodiment will be described, and configurations similar or corresponding to those of the first embodiment are denoted by the same reference numerals in the drawings, or By quoting, overlapping descriptions are omitted as appropriate.

FIG. 18 is a diagram for explaining the processing of the second signal processing section 13 in the fourth modified example of the first embodiment. FIG. 18 is a plan view schematically showing the ship S and its surroundings, showing the first direction range R1 and the second direction range R1 set in the processing of the first signal processing section 12 and the second signal processing section 13. A range R2 is shown as a sample. Further, FIG. 18 illustrates the first directional range R1 and the second directional range R2 in a state where the heading HD of the ship S is changing. In addition, in FIG. 18, the wake WA of the ship S is also schematically shown in order to show the state of change in the bow direction HD of the ship S. As shown in FIG.

In the fourth modification of the first embodiment, when the heading HD of the ship S is changing, the second signal processing unit 13 uses a parameter for specifying the second direction range R2 based on the change in the heading HD. is changed, the second direction range R2 is changed. In the fourth modification of the first embodiment, the parameter specifying the second direction range R2 and changed when the heading HD changes is the parameter of the angle range of the second direction range R2. to select.

More specifically, in the fourth modification of the first embodiment, the second signal processing unit 13 converts the angle range of the second direction range R2 to It is configured to change the second direction range R2 by widening it more than when the bow direction HD of S is not changed. In FIG. 18, the second direction range R2 when the heading HD changes is indicated by a solid double-ended arrow R2, and the boundary lines on both sides of the second direction range R2 when the heading HD changes are indicated by dashed lines. there is Further, in FIG. 18, a second direction range R2 before the change in the heading HD, which is a state in which the heading HD does not change, is indicated by a two-dot chain double-ended arrow R20. Boundaries on both sides of the direction range R2 are indicated by two-dot chain lines. As shown in FIG. 18, in the fourth modification of the first embodiment, the second signal processing unit 13 adjusts the angle range of the second direction range R2 when the bow direction HD of the ship S changes. The second direction range R2 is changed by making it wider than when it is not changed. When the second signal processing unit 13 changes the second direction range R2 when the heading HD of the ship S changes, the first signal processing unit 12 changes the , the first directional range R1 is changed so that the first directional range R1 is always adjacent to the second directional range R2 in the direction of the azimuth angle θ.

According to the fourth modification of the first embodiment, when the heading HD of the ship S is changing, by changing the parameter for specifying the second direction range R2 based on the change in the heading HD, Change the bi-directional range R2. Thereby, the second directional range R2 can be changed so that the trawl fishing gear 100 whose position relative to the vessel S changes when the bow direction HD of the vessel S changes exists in the second directional range R2.

Furthermore, according to the fourth modification of the first embodiment, the second signal processing unit 13 sets the angle range of the second direction range R2 to The second direction range R2 is changed by making it wider than when it is not changed. Therefore, even if the relative position of the trawl fishing gear 100 with respect to the vessel S changes as the bow direction HD changes, the trawl fishing gear 100 does not deviate from the second directional range R2 and remains stable within the second directional range R2. The second directional range R2 can be changed such that

(Second embodiment)
Next, a second embodiment of the invention will be described. FIG. 19 is a block diagram showing the configuration of the signal processor 4a of the underwater detection device of the second embodiment. In the following description of the second embodiment, points different from the above-described first embodiment will be described, and configurations similar or corresponding to those of the first embodiment will be denoted by the same reference numerals in the drawings. , or by citing the same reference numerals to omit redundant description as appropriate.

The underwater detection device of the second embodiment differs from the underwater detection device 1 of the first embodiment in the configuration of the signal processor 4a. Specifically, the underwater detection device of the second embodiment further includes a mark position setting unit 15 in the signal processor 4a, and the video signal generation unit 14, based on the setting result of the mark position setting unit 15, This differs from the underwater detection device 1 of the first embodiment in that a trawl mark video signal for displaying the mark of the trawl fishing gear 100 on the display unit 5 is further generated.

The mark position setting unit 15 sets the position corresponding to the echo identified as the echo corresponding to at least part of the trawl fishing gear 100 towed by the vessel S as the mark setting position, which is the position where the mark of the trawl fishing gear 100 is displayed. do. Based on the first echo signal and the second echo signal, the image signal generation unit 14 generates an echo image signal for displaying the echo of the target on the display unit 5, and the mark position setting unit 15 sets the echo image signal. A trawl mark video signal is further generated for displaying the mark of the trawl fishing gear 100 at the marked mark setting position.

20 and 21 are diagrams schematically showing examples of images displayed on the display screen of the display unit 5 based on the processing of the underwater detection device of the second embodiment. As shown in FIGS. 20 and 21, in the second embodiment, a three-dimensional area image displayed on the display unit 5 based on the echo image signal generated by the image signal generation unit 14 is viewed from a plurality of viewpoints. 3 illustrates a form in which three-dimensional area images (IM1, IM2, IM3) are displayed on the display unit 5. FIG. The three-dimensional area image IM1 is displayed as an image viewed from an obliquely upper viewpoint, which is a viewpoint for obliquely viewing the detection area DR from above the ship S. The three-dimensional area image IM2 is displayed as an image viewed from a vertical viewpoint, which is a viewpoint for viewing the detection area DR in the vertical direction from above the ship S. The three-dimensional area image IM3 is displayed as an image viewed from a horizontal viewpoint, which is a viewpoint for viewing the detection region DR in the horizontal direction from the side of the detection region DR. FIGS. 20 and 21 illustrate a state in which three 3D area images (IM1, IM2, and IM3) are displayed side by side on the same display screen of the display unit 5. FIG.

In any of the three-dimensional area images (IM1, IM2, IM3) displayed on the display unit 5, the first echo signal and the second echo signal generated by the first signal processing unit 12 and the second signal processing unit 13 An echo of the target is displayed on the display screen of the display unit 5 based on the echo image signal generated by the image signal generation unit 14 . Specifically, in any of the three-dimensional area images (IM1, IM2, IM3), the first echo signal generated by the first signal processing unit 12 is converted into the echo video signal generated by the video signal generation unit 14. Based on this, echoes (E1, E2, E3) of the target as a school of fish are displayed on the display screen of the display unit 5. FIG. Then, in any of the three-dimensional area images (IM1, IM2, IM3), based on the echo image signal generated by the image signal generation unit 14 from the second echo signal generated by the second signal processing unit 13, Target echoes (E4, E5) of the trawl fishing gear 100 are displayed on the display screen of the display unit 5. FIG. 20 and 21 exemplify a form in which the echoes of the otter board 101 of the trawl fishing gear 100 are displayed as the echoes (E4, E5) corresponding to the second echo signal.

In this embodiment, three 3D area images (IM1, IM2, and IM3) are displayed on the display unit 5 as an example. The three-dimensional area images (IM1, IM2, IM3) displayed on the display unit 5 may be switched as appropriate based on the user's operation. For example, as an example, when the user appropriately operates an operation device (not shown) such as a keyboard or pointing device of the underwater detection device of the present embodiment, three-dimensional area images (IM1, IM2, IM3) are displayed on the display unit 5. may be displayed, or any one or two of the 3D area images (IM1, IM2, IM3) may be displayed.

The mark position setting unit 15 sets the position corresponding to the echo identified as the echo corresponding to at least part of the trawl fishing gear 100 as the mark setting position where the mark of the trawl fishing gear 100 is to be displayed. When setting the mark setting position, the mark position setting unit 15 identifies an echo corresponding to at least a part of the trawl fishing gear 100 and sets the mark setting position based on the user's operation of the underwater detection device. Alternatively, the mark position setting unit 15, for example, among the echoes detected within the second directional range R2, identifies echoes having a signal strength level equal to or higher than a predetermined value as echoes corresponding to at least part of the trawl fishing gear 100, and A mark setting position may be set. In the second embodiment, the mark position setting unit 15 is configured to identify an echo corresponding to at least a part of the trawl fishing gear 100 and set the mark setting position based on the user's operation of the underwater detection device. It is

When setting the mark setting position, the mark position setting unit 15 identifies the selected echo as the echo corresponding to the trawl fishing gear 100 based on the input by the operation of selecting the echo by the user of the underwater detection device, and sets the mark. Set the setting position. More specifically, the user first operates a pointing device, such as a mouse, of the underwater detector, and displays the position of the cursor displayed on the display screen of the display unit 5 on the display screen of the display unit 5. It moves to the position of echo E4 or echo E5 in the three-dimensional area image IM3 viewed from the horizontal viewpoint. Then, the user clicks the pointing device on the echo E4 or echo E5 on which the cursor has been moved to select the echo E4 or echo E5. By this operation, an input by operation for selecting echo E4 or echo E5 is made to the signal processor 4a. When this input is made, the depth of the otter board 101 of the trawl fishing gear 100 to which Echo E4 or Echo E5 corresponds is determined.

When the above operation is performed by the user and the depth of the otter board 101 is determined, the user then moves the 3D area image IM1 viewed from an obliquely upward viewpoint or the 3D area image IM2 viewed from a vertical viewpoint horizontally. An operation is performed to select the same echo as the echo selected in the three-dimensional area image IM3 viewed from the viewpoint. Thereby, the horizontal distance and the azimuth angle θ of the otter board 101 from the ship S to which the echo E4 or echo E5 selected by the user corresponds are determined.

As described above, the user selects the echo E4 or the echo E5 from the horizontal viewpoint three-dimensional area image IM3 and from the oblique upper viewpoint three-dimensional area image IM1 or the vertical viewpoint three-dimensional area image IM2. The depth of the otter board 101 corresponding to the echo E4 or echo E5, the horizontal distance from the ship S, and the azimuth angle θ are determined by performing the operation. As a result, the coordinates of the otter board 101 corresponding to the echo E4 or echo E5 are determined. When the coordinates of the otter board 101 corresponding to the echo E4 or the echo E5 are determined based on the user's operation, the user can also determine the other of the echo E4 or the echo E5 corresponding to the otter board 101 whose coordinates have been determined. , do the same. For example, first, for the echo E4, a selection operation in the horizontal viewpoint three-dimensional area image IM3 and a selection operation in the oblique upper viewpoint three-dimensional area image IM1 or the vertical viewpoint three-dimensional area image IM2 are performed. When the coordinates of the otter board 101 to which the echo E4 corresponds are determined, the user then performs a similar operation for the echo E5. Thus, for echo E5 as well as echo E4, the selection operation in the horizontal viewpoint three-dimensional area image IM3 and the selection operation in the oblique upper viewpoint three-dimensional area image IM1 or the vertical viewpoint three-dimensional area image IM2 are performed. is performed, and the depth of the otter board 101 to which the echo E5 corresponds, the horizontal distance from the ship S, and the azimuth angle θ are also determined. This also determines the coordinates of the otter board 101 to which the echo E5 corresponds.

As described above, the mark position setting unit 15 sets the selected echoes (E4, E5) to the otter of the trawl fishing gear 100 based on the input by the operation of selecting the echoes (E4, E5) by the user of the underwater detection device. Identifies the echo as corresponding to board 101 . Then, the mark position setting unit 15 sets the mark setting position at the coordinate position of the otter board 101 corresponding to the echoes (E4, E5). In the second embodiment, both Echo E4 and Echo E5 are selected in order by the user, and the mark position setting unit 15 causes Echo E4 and E5 to be positioned at the coordinates of the two otter boards 101 corresponding to each other. Although the form in which the mark setting position is set has been exemplified, this does not have to be the case. Only one of echo E4 and echo E5 is selected by the user, and the mark position setting unit 15 places a mark at the coordinate position of one otter board 101 corresponding to one of the selected echo E4 and echo E5. A form in which the setting position is set may be implemented.

As described above, when the mark setting position is set by the mark position setting unit 15, the video signal generation unit 14 generates a troll mark video signal for displaying the mark TM of the trawl fishing gear 100 at the mark setting position. . Note that the troll mark video signal also includes information on the mark setting position set by the mark position setting unit 15 . FIG. 21 exemplifies a form in which the mark TM of the trawling gear 100 is displayed in each of the three-dimensional area images (IM1, IM2, IM3) of the oblique upper viewpoint, the vertical viewpoint, and the horizontal viewpoint. FIG. 22 is an enlarged view of a part of an example of the image shown in FIG. 21, and is an enlarged view of the three-dimensional area image IM1.

After generating the troll mark video signal for displaying the mark TM of the trawl fishing gear 100 , the video signal generation unit 14 outputs the generated troll mark video signal to the display unit 5 . Based on the input troll mark video signal, the display unit 5 displays the mark TM indicating the trawling gear 100 in each of the three-dimensional area images (IM1, IM2, IM3) as the mark set by the mark setting unit 15. Display at the set position.

The video signal generator 14 generates a troll mark video signal for displaying the mark M1 and the mark M2 as the marks TM of the trawl fishing gear 100 on the display unit 5, as illustrated in FIGS. The mark M1 is configured as the mark of the otter board 101, and the mark M2 is configured as the mark of the mouth opening 102a of the net 102. As shown in FIG. In addition, the video signal generation unit 14 of the second embodiment causes the display unit 5 to display the mark M3 and the mark M4, which are marks other than the mark M1 of the otter board 101 and the mark M2 of the mesh mouth 102a, together with the mark M1 and the mark M2. It is configured to generate a troll mark video signal for. Note that the mark M3 is configured as a mark for the warp 103, and the mark M4 is configured as a mark for the wire 104. FIG. In addition, in FIGS. 21 and 22, the marks (M1, M2, M3, M4) are illustrated by two-dot chain lines.

In addition, the video signal generation unit 14 assigns colors different from the colors assigned to the target echoes (E1, E2, E3, E4, E5) to the marks (M1, M2, M3, M4) to produce a troll mark image. Generate a signal. That is, echo video signals for displaying echoes (E1, E2, E3, E4, E5) and troll mark video signals for displaying marks (M1, M2, M3, M4) are displayed on the display unit 5. Information on different colors is included as information on display colors when displayed. Then, on the display unit 5, the images of the marks (M1, M2, M3, M4) are displayed in colors based on the display color information included in the troll mark image signal. For example, in the display unit 5, the background color of the display screen is set to black, the echoes (E1, E2, E3, E4, E5) are displayed in red, green, and blue, and the marks (M1, M2, M3, M4) is displayed in white.

Various setting values used by the video signal generator 14 to generate the troll mark video signals for displaying the marks (M1, M2, M3, M4) are stored in the signal processor 4a. However, the various setting values described above may be changed by the user appropriately operating an operating device such as a keyboard or pointing device of the underwater detection device. The above-mentioned various setting values include, for example, the distance between the mark M1 of the otter board 101 and the mark M2 of the net mouth 102a, the size of the mark M1 of the otter board 101 (that is, the height and length of the mark M1 of the otter board 101). and thickness), the size of the mark M2 of the mesh mouth 102a (that is, the width and height dimensions of the mark M2 of the mesh mouth 102a), the inclination angle of the mark M2 of the mesh mouth 102a with respect to the vertical plane, and the like. mentioned.

In addition, the video signal generator 14 generates the marks of the otter board 101 together with the echo video signals for displaying the target echoes (E1 to E5) and the troll mark video signals for displaying the marks (M1 to M4). It is also configured to generate a video signal for displaying on the display unit 5 vertical planes (VS1, VS2) including the mark setting position where M1 is displayed. In the second embodiment, for example, a form in which vertical planes (VS1, VS2) are displayed in the three-dimensional area image IM1 displayed on the display unit 5 is exemplified. The vertical plane VS1 is configured as a plane including a vertical line extending vertically downward from a position immediately below the ship S and a vertical line extending vertically from the center position of the mark M1 of the otter board 101 to which the echo E4 corresponds. be done. The vertical plane VS2 is defined as a plane including a vertical line extending vertically downward from a position immediately below the ship S and a vertical line extending vertically from the center position of the mark M1 of the otter board 101 to which the echo E5 corresponds. , consists of In the display unit 5, the target echoes (E1 to E5) and marks (M1 to M4) as well as the vertical planes (VS1, VS2) are displayed as a three-dimensional area image based on the video signal generated by the video signal generation unit 14. Displayed in IM1.

The video signal generator 14 is also configured to generate cross-sectional video signals for causing the display 5 to display echoes of targets included in the vertical planes (VS1, VS2). More specifically, the video signal generation unit 14 generates a cross-sectional video signal for displaying on the display unit 5 the echo E4 of the target as the otter board 101 included in the vertical plane VS1. The video signal generation unit 14 also generates a cross-sectional video signal for displaying on the display unit 5 the echo E5 of the target as the otter board 101 included in the vertical plane VS2. FIG. 21 illustrates slice images (IM4, IM5) displayed on the display screen of the display unit 5 based on the slice image signal generated by the image signal generation unit 14 .

The cross-sectional image IM4 is displayed based on a cross-sectional image signal for causing the display unit 5 to display the echo E4 of the target as the otter board 101 included in the vertical plane VS1. The cross-sectional image IM5 is displayed based on a cross-sectional image signal for causing the display unit 5 to display the echo E5 of the target as the otter board 101 included in the vertical plane VS2. In the cross-sectional image IM4, a cross-sectional image of the echo E4 on the vertical plane VS1 is displayed. In the cross-sectional image IM5, a cross-sectional image of the echo E5 on the vertical plane VS2 is displayed. As a result, the user viewing the images displayed on the display unit 5 can confirm the cross-sectional images (IM4, IM5) together with the three-dimensional area images (IM1, IM2, IM3). 101 can be grasped in more detail.

Further, in the second embodiment, the mark position setting unit 15 sets the mark around the rotation center position set at the position corresponding to the position of the ship S when the bow direction HD of the ship S is changing. Configured to rotate position. 23 and 24 are diagrams for explaining the processing of the mark position setting section 15 in the signal processor 4a of the underwater detection device of the second embodiment, and are for explaining the processing for rotating the mark setting position. It is a diagram.

When the mark position setting unit 15 performs the process of setting the mark setting position at the coordinate position of the otter board 101 based on the selection operation of the echoes (E4, E5) by the user, when the heading direction HD changes, the mark setting position to rotate. In this process, once the mark setting position is set, the mark position setting unit 15 first specifies the position of the middle point P1 between the two otter boards 101 as shown in FIG. The position of the intermediate point P1 between the two otter boards 101 is the center position of the mark M1 when displaying the mark M1 corresponding to the echo E4, and the center position of the mark M1 when displaying the mark M1 corresponding to the echo E5. , is specified as the midpoint of

After specifying the positions of the midpoints P1 of the two otter boards 101, the mark position setting unit 15 then obtains the horizontal distance between the midpoints P1 and the ship S in the horizontal direction. The horizontal distance between the ship S and the intermediate point P1 is the distance between the ship S and the intermediate point P1 when the ship S and the two otter boards 101 are viewed from the horizontal direction and the vertical direction as shown in FIG. is the horizontal distance between After obtaining the horizontal distance between the ship S and the intermediate point P1, the mark position setting unit 15 specifies the same-distance track point P2, which is a point on the track WA whose distance from the ship S is the same as the horizontal distance. . In FIG. 23, the circle EDL, which is a set of points whose distance from the ship S is equal to the horizontal distance between the ship S and the intermediate point P1, is indicated by a chain double-dashed line.

The ship S is equipped with a GPS antenna (not shown) for receiving radio waves transmitted from positioning satellites, and a GPS receiver (not shown) for detecting the position of the ship S based on the positioning signal received by the GPS antenna. It is The GPS receiver is connected to the signal processor 4a and configured to output the detected position of the ship S to the signal processor 4a. The signal processor 4a acquires data of the wake WA of the ship S as time series data of the position of the ship S input from the GPS receiver. When the mark position setting unit 15 obtains the same distance track point P2, which is a point on the track WA at which the horizontal distance between the ship S and the intermediate point P1 is the same as the distance from the ship S, the mark position setting unit 15 Search along WA for the location of the first intersection point where track WA meets circle EDL. The mark position setting unit 15 obtains this intersection point as the same distance track point P2.

When the same-distance track point P2 is obtained, the mark position setting unit 15 sets the angle θ0 formed by the stern direction TD and the same-distance track point direction WD, which is the direction of the same-distance track point P2 with respect to the ship S, to the initial angle θ0 set as In FIG. 23, the same-distance wake point direction WD is indicated by a broken line, and the stern direction TD is indicated by a dashed line. The mark position setting unit 15 sets the initial angle θ0, which is the angle formed by the same-distance track point direction WD and the stern direction TD, at the timing when the mark setting position is set based on the echo (E4, E5) selection operation by the user. Ask for

If the heading direction HD of the ship S does not change between the time when the ship S passes through the position corresponding to the same-distance track point P2 and the time when the mark position is set by the mark position setting unit 15, The initial angle θ0 is zero. In this case, once the mark setting position is set, the mark position setting unit 15 does not rotate the mark setting position unless the bow direction HD of the ship S changes.

On the other hand, the mark position setting unit 15 rotates the mark setting position as shown in FIG. 24 when the bow direction HD of the ship S is changed after setting the mark setting position. The rotation of the mark setting position when the heading HD changes is performed each time the data obtaining unit 10 obtains data on the heading.

The mark position setting unit 15 obtains the same-distance track point P2 as shown in FIG. The angle θ1 formed by the distance track point direction WD is obtained as the heading direction change angle θ1. Even when the heading HD changes, the same-distance track point P2 is obtained by the same processing as when the initial angle θ0 is set after setting the mark setting position. When the heading direction change angle θ1 is obtained, the mark position setting unit 15 rotates to a position corresponding to the position of the ship S by the angle difference (θ1−θ0) between the bow direction change angle θ1 and the initial angle θ0. Rotate the mark setting position around the center position. In FIG. 24, the two otter boards 101 and their intermediate point P1 are shown in a state where the mark setting positions are rotated by the angle difference (.theta.1-.theta.0) when the heading HD changes.

When the mark position setting unit 15 rotates the mark setting position when the bow direction HD changes, the video signal generating unit 14 rotates the mark setting position rotated around the position of the ship S. A troll mark video signal for displaying the mark M1 is generated. In addition, the video signal generation unit 14 places a mark M2 of the net mouth 102a, a mark M3 of the warp 103, and a mark M4 of the wire 104 at positions rotated about the position of the ship S corresponding to the mark M1 of the otter board 101. It also generates a troll mark video signal for displaying . The generated trawl mark video signal is output to the display unit 5, and the mark TM of the trawl fishing gear 100 and the mark M3 of the warp 103 are displayed on the display unit 5 at positions rotated around the position of the ship S. . That is, in the display unit 5, when the heading HD changes, the two marks M1 of the otter board 101, the mark M2 of the net mouth 102a, and A mark M3 of the warp 103 and a mark M4 of the wire 104 are displayed.

The underwater detection device of the second embodiment is, like the underwater detection device 1 of the first embodiment, configured as an underwater detection device used on a ship S for trawl fishing, and includes a transducer 2 and a second signal A processing unit 13 is provided. The underwater detection device of the second embodiment further includes the video signal generator 14 and the mark position setting unit 15 described above. For this reason, the underwater detection apparatus of the second embodiment includes the transducer 2 as a transmitting transducer that transmits transmission waves toward the trawl fishing gear 100 in the water, and the reception waves including the reflection of the transmission waves at the trawl fishing gear 100. Transceiver 2 as a reception transducer that receives and generates a reception signal from the received reception wave, a second signal processing unit 13 as a signal processing unit that acquires an echo signal from the reception signal, and an echo based on the echo signal The position corresponding to the echo identified as the echo corresponding to at least a part of the trawl fishing gear 100 is set as the mark setting position where the mark TM of the trawl fishing gear 100 is to be displayed. and a mark position setting unit 15 for setting. Then, the video signal generation unit 14 further generates a trawl mark video signal for displaying the mark TM of the trawl fishing gear 100 at the mark setting position, and the mark position setting unit 15 generates a trawl mark video signal for displaying the mark TM of the trawl fishing gear 100 at the mark setting position. The mark setting position is configured to rotate around a rotation center position set at a position corresponding to the position of the ship S when the ship S is in the water.

According to the second embodiment, the mark TM of the trawl gear 100 can be displayed at the position corresponding to the echoes (E4, E5) identified as the echoes (E4, E5) corresponding to the trawl gear 100. Therefore, since the user can visually recognize the echoes (E4, E5) of the trawl fishing gear 100 together with the mark TM of the trawl fishing gear 100, the user can grasp the state of the trawl fishing gear 100 more easily and clearly.

Further, according to the second embodiment, when the bow direction HD is changing, the mark TM of the trawl fishing gear 100 can be displayed by rotating around the position of the ship S according to the change in the bow direction HD. can. Therefore, the user can more easily and clearly recognize that the direction of the trawl fishing gear 100 with respect to the vessel S is changing when the heading HD is changing.

(Modification of Second Embodiment)
FIG. 25 is a diagram for explaining a modification of the second embodiment, and is a diagram for explaining processing in the modification of the second embodiment. In the following description, differences from the first embodiment, the second modification of the first embodiment, and the second embodiment will be described, and the first embodiment and the second modification of the first embodiment will be described. Examples and configurations similar to or corresponding to those in the second embodiment are given the same reference numerals in the drawings, or the same reference numerals are used to omit redundant description as appropriate.

FIG. 25 is a diagram for explaining processing of the video signal processing unit 14 in the modified example of the second embodiment. FIG. 25 shows echoes (E1, E2, E3, E7) of targets as a school of fish and marks of the trawl fishing gear 100 based on the echo image signal and the troll mark image signal generated by the image signal generation unit 14. A form in which a three-dimensional area image IM1 including TM and is displayed on the display unit 5 is exemplified.

In the modified example of the second embodiment, as in the second modified example of the first embodiment, the first signal processing unit 12 sets the first directional range R1 in which the first echo signal is acquired to Set as a directional range over the entire circumference. In the modified example of the second embodiment, as in the second modified example of the first embodiment, the first directional range R1 and the second directional range R2 have overlapping directional ranges. Schools of fish are also detected in the area for detecting . That is, as shown in FIG. 25, the echo E7 of the fish school detected in the second directional range R2 can also be displayed on the display section 5. FIG.

Further, in the modified example of the second embodiment, switching between a display ON state in which the echoes (E4, E5) of the trawl fishing gear 100 are displayed on the display unit 5 and a display OFF state in which the echoes (E4, E5) of the trawl fishing gear 100 are not displayed is performed based on the user's operation. is configured so that In the display ON state in which the echoes (E4, E5) of the trawl fishing gear 100 are displayed on the display unit 5, similar to the second embodiment, based on the echo video signal and the troll mark video signal generated by the video signal generation unit 14, Then, the echoes (E4, E5) of the trawl fishing gear 100 and the mark TM of the trawl fishing gear 100 are displayed on the display section 5. FIG.

On the other hand, when switching from the display ON state to the display OFF state in which the echoes (E4, E5) of the trawl fishing gear 100 are not displayed on the display unit 5 based on the user's operation, the mark TM of the trawl fishing gear 100 is displayed. is maintained, and the echoes (E4, E5) of the trawling gear 100 are not displayed (see FIG. 25). The switching operation from the display ON state to the display OFF state by the user is performed, for example, by the user appropriately operating an operating device such as a keyboard or a pointing device. Note that the operation to switch from the display ON state to the display OFF state is performed after the mark TM of the trawl fishing gear 100 is once displayed on the display unit 5 .

When the user performs a switching operation from the display ON state to the display OFF state, the video signal generation unit 14 displays the echoes (E1, E2, E3, E7) of the target as a school of fish on the display unit based on the first echo signal. 5 and a troll mark video signal for displaying the mark TM of the trawl fishing gear 100 on the display unit 5 and output to the display unit 5 . In the display OFF state, the video signal generation unit 14 does not generate an echo video signal for displaying the echoes (E4, E5) of the target as the trawl fishing gear 100 based on the second echo signal on the display unit 5. . Therefore, in the display OFF state, the display unit 5 displays the echoes of the school of fish (E1, E2, E3, E7) and the mark TM of the trawl fishing gear 100, and displays the echoes of the trawl fishing gear 100 (E4, E5). It will be in a state where it will not be

In addition, in the modification of the second embodiment, even in the display OFF state where the mark TM of the trawl fishing gear 100 is displayed and the echoes (E4, E5) of the trawl fishing gear 100 are not displayed, the bow direction HD of the vessel S changes. If so, the mark position setting section 15 rotates the mark setting position. Then, the video signal generator 14 generates a trawl mark video signal for displaying the mark TM of the trawl fishing gear 100 at the mark setting position rotated around the position of the ship S, and outputs it to the display unit 5 . Therefore, on the display unit 5, when the heading HD changes, the mark TM of the trawl fishing gear 100 is displayed at a position rotated around the position of the vessel S according to the change.

According to the modified example of the second embodiment, by switching from the display ON state to the display OFF state, the echoes (E1, E2, E3, E7) of the school of fish and the mark TM of the trawl fishing gear 100 are displayed on the display unit 5. and the echoes (E4, E5) of the trawl fishing gear 100 are not displayed. Therefore, it is possible to detect a school of fish in the wide first directional range R1 including the second directional range R2, display its echoes (E1, E2, E3, E7), and easily distinguish them from the echoes. The trawl gear 100 can be displayed as a mark TM of the trawl gear 100 .

(Other modifications)
Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to these, and various modifications are possible without departing from the gist of the present invention.

(1) In the above-described embodiment and modifications, an underwater detection device having a transducer that functions as both a transmitting transducer and a receiving transducer has been described as an example, but this does not have to be the case. For example, a form of underwater sounding device with separate transmitting and receiving transducers may be implemented.

(2) In the above-described embodiment and modifications, an underwater detection device equipped with a scanning sonar that simultaneously forms transmission beams in all directions underwater around a ship has been described as an example. It doesn't have to be. For example, a form of underwater detection system with a searchlight sonar (PPI sonar) that rotates the transmit and receive beams may be implemented. In addition, in the above-described embodiment and modified examples, the form of an underwater detection device equipped with a three-dimensional scanning sonar has been described as an example, but this does not have to be the case, and the underwater detection device equipped with a two-dimensional scanning sonar may be used. may be implemented.

(3) In the above-described embodiment and modification, the second signal processing unit sets the second direction range to the direction range centering on the stern direction, but this need not be the case. . A second signal processing unit obtains a direction to the ship at the intersection of a circle centered on the position of the ship and having a radius equal to the warp length and the wake of the ship, and calculates a second direction in a direction range centered on the direction to the ship at the intersection. Forms of setting ranges may also be implemented. Further, the second signal processing unit calculates the magnitude of the angle difference between the direction of the intersection with respect to the ship and the stern direction, and further calculates the second direction range by a constant multiple of the magnitude of the angle difference. A wide configuration may also be implemented.

(4) In the above-described embodiment and modified example, the warp length of the warp is measured by an encoder that detects the number of revolutions of the top roller that is provided at the stern of the ship and rotates during the warp payout and retraction operations. Although the form measured by the device has been described as an example, it does not have to be this way. An embodiment may be implemented in which when the user performs an input to select the echo of the otter board, the distance between the ship and the otter board is calculated based on the input, and the warp length is calculated.

(5) In the above-described second embodiment and its modified example, an example has been described in which the mark of the trawl fishing gear is displayed together with the echo of the school of fish. Numerical information regarding the trawl fishing gear is also displayed together with the mark of the trawl fishing gear. Any form may be implemented. In this case, numerical information such as the linear distance between the vessel and the otterboard, the horizontal distance between the vessel and the otterboard, the depth of the otterboard or mouth of the net, the distance between the two otterboards, etc. may be used to mark the trawl gear. may be implemented.

(6) In the modified example of the second embodiment described above, the second signal processing unit 13 further processes the second echo signal from within the second direction range R2 as in the third modified example of the first embodiment. is obtained from a received signal corresponding to a received wave having an arrival azimuth angle of and arriving within a predetermined distance range DX away from the transducer 2 as a receiving transducer. may be implemented. Further, in this case, of the distance median value and the distance width that define the predetermined distance range DX, the distance width is set by the user's operation, and the distance median value is set by the mark position setting unit 15. may be set as the distance between the mark setting position and the ship S.

(7) The video signal generator may perform known signal processing or image processing such as TVG (time varied gain) and interference removal on the first echo signal and the second echo signal. Further, a mode may be implemented in which the video signal generation unit performs these processes under conditions such that the effects on the first echo signal and the second echo signal are different.

INDUSTRIAL APPLICABILITY The present invention can be widely applied as an underwater detection device and an underwater detection method for detecting an underwater target.

1 Underwater detection system 2 Transceiver (transmitting transducer, receiving transducer)
4 signal processor 5 display unit 11 Doppler shift calculator 12 first signal processor 13 second signal processor 14 video signal generator

Claims (20)

An underwater detection device for use on a ship,
a transmitting transducer for transmitting transmitted waves into water;
a receiving transducer for receiving received waves including reflections of said transmitted waves from targets in water and for generating received signals from said received waves;
a Doppler shift calculator that calculates a frequency shift amount caused by shifting the frequency of the received wave with respect to the frequency of the transmitted wave;
A first signal processing unit that acquires a first echo signal from the received signal based on the frequency shift amount, wherein the first echo signal is converted to the received wave having an arrival azimuth angle from within a first direction range. a first signal processor that obtains from the corresponding received signal;
A second signal processing unit that obtains a second echo signal from the received signal independently of the frequency shift amount, wherein the second echo signal is obtained from within a second direction range different from the first direction range. a second signal processing unit obtained from the received signal corresponding to the received wave having an azimuth of arrival of
a video signal generation unit that generates an echo video signal for displaying the echo of the target on a display unit based on the first echo signal and the second echo signal;
An underwater detection device comprising: An underwater detection device according to claim 1,
The underwater detection device, wherein the first range of directions includes the bow direction of the ship, and the second range of directions includes the stern direction of the ship. The underwater detection device according to claim 1 or claim 2,
The second signal processing unit changes a parameter for specifying the second direction range based on the change in the heading direction when the heading direction of the ship is changing, thereby determining the second direction range. An underwater detection device characterized by: The underwater detection device according to any one of claims 1 to 3,
The second signal processing unit changes the direction of a center line that bisects the second direction range into equal angle ranges based on the change in the bow direction when the bow direction of the ship is changing. and wherein the second range of directions is changed. The underwater detection device according to any one of claims 1 to 4,
The second signal processing unit changes the direction of a center line that bisects the second direction range into equal angle ranges counterclockwise when the bow direction of the ship changes clockwise. and wherein the second range of directions is changed. The underwater detection device according to any one of claims 1 to 5,
The second signal processing unit widens the angle range of the second direction range when the bow direction of the ship is changing, compared to when the bow direction of the ship is not changing. An underwater detection device characterized by changing two-way ranges. The underwater detection device according to any one of claims 1 to 6,
An underwater detection device, wherein the angle range of the first direction range is wider than the angle range of the second direction range. The underwater detection device according to any one of claims 1 to 7,
The first signal processing unit mixes the received signal with a local signal having a frequency adjusted based on the frequency shift amount, or by a filter whose frequency characteristics are adjusted based on the frequency shift amount. An underwater detection apparatus, wherein the first echo signal is obtained by filtering the received signal. The underwater detection device according to any one of claims 1 to 8,
The second signal processing unit mixes the received signal with a local signal having a fixed frequency set based on the frequency of the transmission wave, or the frequency characteristics are adjusted based on the frequency of the transmission wave. and obtaining the second echo signal by filtering the received signal with a filter. The underwater detection device according to any one of claims 1 to 9,
A data acquisition unit that acquires at least one of data on the speed of the ship and data on the warp length of the warp connected between the trawl fishing gear towed by the ship and the ship,
The second signal processing unit acquires the second echo signal by limiting the frequency band of the received signal,
The underwater detection apparatus, wherein the second signal processing unit adjusts the frequency band based on at least one of the ship speed data and the warp length data. An underwater detection device according to claim 10,
An underwater detection device, wherein the frequency band is narrower than in the second state in a first state in which the boat speed is higher than in the second state. An underwater detection device according to claim 10 or claim 11,
An underwater detection apparatus, wherein the frequency band is narrower than in the fourth state in a third state in which the warp length is shorter than in the fourth state. The underwater detection device according to any one of claims 1 to 12,
The video signal generating unit assigns a color different from a color assigned to the echo of the target to which the first echo signal corresponds to the echo of the target to which the second echo signal corresponds, thereby generating the echo video signal. An underwater detection device characterized by: The underwater detection device according to any one of claims 1 to 13,
An underwater sounding device, wherein the second directional range has a directional range that overlaps with the first directional range. The underwater detection device according to any one of claims 1 to 14,
A mark position setting unit that sets a position corresponding to the echo identified as the echo corresponding to at least part of the trawl fishing gear towed by the vessel as a mark setting position, which is a position where the mark of the trawl fishing gear is to be displayed. prepared,
The underwater detection apparatus, wherein the video signal generator further generates a troll mark video signal for displaying the mark of the trawling gear at the mark setting position. An underwater detection device according to claim 15,
The mark position setting unit rotates the mark setting position about a rotation center position set at a position corresponding to the position of the ship when the bow direction of the ship is changing. , an underwater detection device. The underwater detection device according to any one of claims 1 to 16,
The underwater detection apparatus, wherein the second signal processing unit acquires the second echo signal from the received signal corresponding to the received wave arriving from within a predetermined distance range from the receiving transducer. An underwater detection device according to claim 17,
The underwater detection apparatus, wherein the second signal processing unit acquires the second echo signal from the received signal corresponding to the received wave arriving from within a predetermined depth range in water. The underwater detection device according to any one of claims 1 to 18,
An underwater detection device, wherein the first directional range includes the second directional range . send a transmission wave into the water,
receiving a received wave including a reflection of the transmitted wave from an underwater target, generating a received signal from the received received wave;
calculating a frequency shift amount caused by shifting the frequency of the received wave with respect to the frequency of the transmitted wave;
A first echo signal is obtained from the received signal based on the frequency shift amount, and the first echo signal is obtained from the received signal corresponding to the received wave having an azimuth angle of arrival from within a first direction range. ,
A second echo signal is acquired from the received signal independently of the frequency shift amount, and the second echo signal has an arrival azimuth angle from within a second directional range different from the first directional range. obtained from said received signal corresponding to a wave;
An underwater detection method, wherein an echo image signal for displaying the echo of the target on a display unit is generated based on the first echo signal and the second echo signal.

Images