JP6811069B2 - Underwater detection signal processing device, underwater detection device, and underwater detection signal processing method - Google Patents

Description

The present invention mainly relates to an underwater detection signal processing device that detects the underwater around the own machine and generates an underwater detection image.

Conventionally, an underwater detection device that detects underwater by transmitting ultrasonic waves into water and analyzing an echo signal that is a reflected wave thereof has been known. This underwater detection device is known to have a configuration in which a depression angle is set and ultrasonic waves are transmitted to a predetermined range to detect the surroundings of the ship. Patent Document 1 discloses this type of underwater detector.

The underwater detector of Patent Document 1 sets a depression angle, transmits ultrasonic waves in all directions in water, and receives an echo signal which is a reflected wave thereof. The underwater detector of Patent Document 1 determines the level of the echo to be displayed this time based on a predetermined standard based on the echo acquired this time and the echo acquired in the past, and the ultrasonic wave is transmitted by the underwater detector of another ship. It is configured to be able to remove interference waves (unnecessary waves) caused by ultrasonic waves.

Japanese Patent No. 41799699

Here, in the underwater detection device, the farther the reflection position of the transmission signal is from the own device, the longer it takes to receive the echo signal. Therefore, when the underwater detection image is updated according to the timing at which the echo signal is acquired, the underwater detection image is updated so that the newly generated underwater detection image spreads radially. As a result, a break is displayed at the boundary between the underwater detection image before the update and the underwater detection image after the update. The user of the underwater detection device confirms the size and shape of the echo obtained by detecting the water, and confirms what kind of target the echo is reflected. However, it may be difficult to confirm the size and shape of the echo due to the above-mentioned break in the image.

The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide an underwater detection signal processing device that eliminates the difficulty of confirming echoes caused by breaks in underwater detection images before and after updating. It is in.

Means and effects to solve problems

The problem to be solved by the present invention is as described above, and next, the means for solving this problem and its effect will be described.

According to the first aspect of the present invention, an underwater detection signal processing device having the following configuration is provided. That is, this underwater detection signal processing device includes a storage unit, a video generation unit, and a display control unit. The storage unit stores an echo signal which is a reflected wave of ultrasonic waves continuously transmitted in a predetermined range in water. The image generation unit reads out an echo signal obtained by two or more consecutive detections from the storage unit, and generates an interpolated image using the echo signal obtained by the two or more consecutive detections. The display control unit controls to display the interpolated video generated by the video generation unit. Generally, when the echo signal at the time of the kth detection is expressed as the echo signal [k], the image generator echoes when the echo signal up to the middle of the detection distance is obtained in the Nth detection. In the distance range in which the signal [N] has been acquired, the interpolation is performed by increasing the weighting coefficient of the echo signal [N] more than the echo signal [N-1] as the distance from the own machine becomes closer. Generate video. In the distance range in which the echo signal [N] has not yet been acquired, the image painter unit increases the echo signal [N-1] rather than the echo signal [N-2] as the distance from the machine becomes closer. ] By increasing the weighting coefficient, the interpolated image is generated.

According to the second aspect of the present invention, the following underwater detection signal processing method is provided. That is, the ultrasonic wave is transmitted to a predetermined range in the water by using the underwater detection device, and the echo signal which is the reflected wave of the ultrasonic wave is acquired. Generating a complement between images by using the echo signal obtained by the detection least two consecutive of. In addition, control is performed to display the interpolated image. Generally, when the echo signal at the time of the kth detection is expressed as the echo signal [k], when the echo signal up to the middle of the detection distance is obtained in the Nth detection when the interpolated image is generated. In addition, in the distance range in which the echo signal [N] has been acquired, the weighting coefficient of the echo signal [N] is increased as the distance from the underwater detector becomes closer than that of the echo signal [N-1]. As a result, the interpolated video is generated. In the distance range in which the echo signal [N] has not been acquired yet, the weighting coefficient of the echo signal [N-1] is higher than that of the echo signal [N-2] as the distance from the underwater detector becomes closer. By increasing the size, the interpolated image is generated .

As a result, the underwater detection image is smoothly switched by using the interpolated image. Therefore, since the breaks in the image do not occur or are unlikely to occur, it is possible to easily confirm the underwater detection image. As a result, it becomes easy to confirm the shape and size of the echo of interest.

The block diagram which shows the structure of the underwater detection apparatus which concerns on one Embodiment of this invention. The figure which shows the state of detecting underwater by the underwater detection device. The figure which shows the underwater detection image generated by the image generation part. The figure explaining the process of generating an interpolated image while acquiring an echo signal [N] in a predetermined direction. The figure explaining the process of generating an interpolated image while acquiring an echo signal [N + 1] in a predetermined direction. The figure which shows the switching of the echo image performed by the underwater detection apparatus of the conventional example. The figure which shows the switching of the interpolated image performed by the underwater detection apparatus of this embodiment.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the underwater detection device 10. FIG. 2 is a diagram showing a state in which the underwater detection device 10 detects underwater. FIG. 3 is a diagram showing an underwater detection image generated by the image generation unit 32.

The underwater detection device 10 transmits ultrasonic waves to a predetermined range in water (360 degrees in the directional direction in the present embodiment), and also receives an echo signal which is a reflected wave of the ultrasonic waves. The underwater detection device 10 generates and displays an underwater detection image showing a school of fish, the seabed, and the like based on this echo signal. The details of the underwater detection device 10 will be described below.

As shown in FIG. 1, the underwater detection device 10 includes an underwater detection signal processing device 11, a transmission circuit 12, a transmission / reception switch 13, a transmission / reception receiver 14, a reception circuit 15, and an A / D converter 16. A display unit 17 and an operation unit 18 are provided.

The underwater detection signal processing device 11 includes a calculation unit 21 and a storage unit 22. Further, the calculation unit 21 includes a transmission control unit 31, a video generation unit 32, and a display control unit 33.

The arithmetic unit 21 is realized by an arithmetic unit such as FPGA, ASIC, or CPU. The calculation unit 21 is configured to be able to execute various processes related to the underwater detection device 10 by executing a program created in advance. In the following description, among the processes executed by the arithmetic unit 21, transmission control, video generation processing, and video display processing will be described in detail, but the arithmetic unit 21 can also execute other processing (for example, range). Switching, menu display, etc.).

The storage unit 22 is realized by a volatile memory such as a RAM. The storage unit 22 stores the echo signal obtained by two or more consecutive detections.

The transmission control unit 31 controls the transmission of ultrasonic waves. Specifically, the transmission control unit 31 instructs the timing of generating ultrasonic waves, the amplitude of ultrasonic waves, the depression angle at which ultrasonic waves are transmitted (the angle formed by the transmission direction of ultrasonic waves with respect to the water surface, the tilt angle), and the like. A signal is created and output to the transmission circuit 12. The transmission circuit 12 creates a pulse signal based on the signal received from the transmission control unit 31, and outputs the pulse signal to the transmitter / receiver 14 via the transmitter / receiver switch 13.

The transmitter / receiver 14 is an oscillator attached to the bottom of a ship or the like, and transmits ultrasonic waves into water based on a signal received from a transmission circuit 12. The transmitter / receiver 14 is composed of a substantially cylindrical housing and a plurality of oscillators. The plurality of oscillators are attached to the outer peripheral surface of the housing. With this configuration, ultrasonic waves can be simultaneously transmitted to a predetermined azimuth range. In the present embodiment, the transmitter / receiver 14 transmits ultrasonic waves in all directions (360 degrees) at the depression angle specified by the transmission control unit 31 (see FIG. 2). The ultrasonic waves transmitted by the transmitter / receiver 14 have a ring shape in a plan view and travel so as to spread radially. Further, the oscillator of the transmitter / receiver 14 receives the reflected wave reflected by the fish or the seabed of the ultrasonic wave as an echo signal.

Here, in the case of transmitting ultrasonic waves in all directions as in the present embodiment, transmitting ultrasonic waves in all directions and receiving the echo signals in all directions to detect the surroundings is defined as one detection. Express. Further, the directional direction detected by the underwater detection device 10 is not limited to all directions, and may be configured to continue to detect only a set directional range (for example, 180 degrees forward). In this case, transmitting ultrasonic waves to the directional range to be detected, receiving the echo signal of the directional range, and detecting the predetermined directional range is expressed as one detection. Further, the underwater detection device 10 may transmit ultrasonic waves in a plurality of times without simultaneously transmitting ultrasonic waves in the directional range in which detection is performed. For example, when detecting all directions, ultrasonic waves in an azimuth range of 90 degrees may be transmitted in four times. In this case, transmitting and receiving ultrasonic waves in the entire azimuth range for detection is referred to as one detection. Therefore, when the ultrasonic wave in the directional range of 90 degrees is transmitted in four times, the ultrasonic wave is transmitted and received four times, so that the detection is performed once. Further, the underwater detection device 10 transmits ultrasonic waves in only one direction instead of a predetermined azimuth range, and detects a predetermined azimuth range by gradually changing the direction in which the ultrasonic waves are transmitted (PPI sonar, PPI sonar). Search light sonar) may be used.

The transmitter / receiver 14 outputs the received echo signal to the receiver circuit 15 via the transmitter / receiver switch 13. The transmission / reception switch 13 outputs the signal output by the transmission circuit 12 to the transmission / reception device 14, and outputs the echo signal acquired by the transmission / reception circuit 14 to the reception circuit 15.

The receiving circuit 15 amplifies the input echo signal and outputs it to the A / D converter 16. The A / D converter 16 converts the input echo signal from an analog signal to a digital signal and outputs it to the underwater detection signal processing device 11. The echo signal after A / D conversion is stored in the storage unit 22. The echo signal may be stored in the storage unit 22 after performing another process after the A / D conversion.

The image generation unit 32 included in the underwater detection signal processing device 11 processes the echo signal input from the A / D converter 16 or stored in the storage unit 22. Specifically, the image generation unit 32 obtains the distance from the ship based on the time from the transmission of the ultrasonic wave to the reception, and obtains the intensity of the echo signal according to the amplitude (signal level). This process is performed in all directions (detection directions).

In the following description, an image generated by using the echo signal obtained by one detection and using no other echo signal other than noise removal or the like is referred to as an echo image. The conventional underwater detection device is configured to display only this echo image, but the image generation unit 32 of the underwater detection device 10 of the present embodiment generates and displays an interpolated image instead of the echo image. The interpolated image is an image that interpolates two consecutive echo images. In other words, the interpolated image is an image showing the detection result that interpolates the detection result obtained from one echo signal and the detection result obtained from another continuous echo signal. An underwater detection image is an image showing an echo obtained as a result of detecting underwater, such as an echo image displayed by a conventional underwater detection device or an interpolated image displayed by the underwater detection device 10 of the present embodiment. It may be called. The interpolated video generated by the video generation unit 32 is displayed on the display unit 17.

FIG. 3 shows an example of an underwater detection image (specifically, an interpolated image) displayed by the display unit 17. The underwater detection image is a diagram showing the information obtained by detecting underwater in a plan view. Therefore, in the underwater detection image, the distance from the ship to the echo becomes longer (the water depth becomes deeper) as the echo is displayed at a position farther from the center. In the center of the underwater detection image, a triangular own ship mark 51 indicating the position and direction of the own ship is displayed. Further, when detecting in all directions as in the present embodiment, a ring-shaped echo 52 indicating the seabed is displayed. Further, in the underwater detection image of FIG. 3, the echo 53 showing the school of fish is also displayed.

The underwater detection device 10 sequentially acquires new echo signals in order to transmit ultrasonic waves at a predetermined transmission cycle for detection. The image generation unit 32 generates an interpolated image based on the new echo signal and the echo signal acquired immediately before (details will be described later). The interpolated image generated in this way is displayed on the display unit 17 while being switched by the display control unit 33 at a predetermined timing. When referred to as an echo image, an interpolated image, or an underwater detection image, the images in all directions may be shown together, but the images in a predetermined area or a predetermined direction may be shown only.

The operation unit 18 has a predetermined physical key, and is configured to be able to accept operations by the user. The content of the operation performed by the user on the operation unit 18 is output to the underwater detection signal processing device 11 or the like, and the user's instruction is reflected. By operating the operation unit 18, the user can instruct, for example, switching the range, whether or not to display the interpolated image, the number of displayed sheets of the interpolated image per unit time, and the like. The operation unit 18 may be attached to the housing of the display unit 17 or may be separate from the display unit 17. Further, a touch panel type display can be adopted, and the display unit 17 and the operation unit 18 can be integrally configured.

Next, a method of generating the interpolated video will be described with reference to FIGS. 4 and 5. FIG. 4 is a diagram illustrating a process of generating an interpolated image while acquiring an echo signal [N] in a predetermined direction. FIG. 5 is a diagram illustrating a process of generating an interpolated image while acquiring an echo signal [N + 1] in a predetermined direction. Further, in the following description, the echo signal obtained by the kth detection is referred to as an echo signal [k].

In general, the time it takes from transmitting an ultrasonic wave to receiving an echo signal depends on the distance from the ship (specifically, the transmitter / receiver 14 of the underwater detector 10; the same applies hereinafter) to the target. .. Therefore, in the Nth detection, when the underwater detection image based on the echo signal [N] is generated after the echo signal from the farthest distance is returned, the time from detection to drawing becomes long, and the real-time property is improved. descend. Therefore, in the present embodiment, in the Nth detection, the generation of the interpolated image using the echo signal [N] is started from the region where the echo signal [N] has been acquired (that is, from the region close to the own ship). In this way, by making the timing of using the Nth echo different according to the distance from the own machine, the Nth echo can be used at an early timing, and the real-time property is improved.

Further, the image generation unit 32 of the present embodiment generates an interpolated image based on the echo signal obtained by two consecutive detections. Specifically, an interpolated image is generated by applying a weighting coefficient to each of the echo signals obtained by two consecutive detections and taking a linear sum. In FIGS. 4 and 5, echo signals acquired in a predetermined direction are shown side by side. The echo signal described above is the newly acquired echo signal. In addition, the horizontal axis shows the distance from the own ship, and the farther to the right, the farther from the own ship. At the time shown in FIG. 4, for the echo signal [N-2] and the echo signal [N-1], all the echo signals up to the set distance R have been acquired, and for the echo signal [N], the distance. The echo signal has been acquired up to X1. As shown in FIG. 4, the region where the echo signal [N] has been acquired is referred to as the region where the echo signal [N] has been acquired, and the region where the echo signal [N] has not been acquired yet (the region from the own ship rather than the region where the echo signal has been acquired). The region where the distance is long) is referred to as an echo signal unacquired region. Therefore, in the example of FIG. 4, the distance range from the distance 0 to the distance X1 corresponds to the echo signal acquired region, and the distance range from the distance X1 to the distance R corresponds to the echo signal unacquired region.

As described above, since the image generation unit 32 starts generating an interpolated image using the echo signal [N] from the echo signal acquired area, the echo signal [N] and the echo signal are generated in the echo signal acquired area. An interpolated image is generated using [N-1]. Further, in the echo signal unacquired region, an interpolated image is generated using the echo signal [N-1] and the echo signal [N-2].

The image generation unit 32 generates an interpolated image using the data obtained by convexly combining the echo signals obtained by the two consecutive detections. Specifically, as shown in FIG. 4, the echo signal data (specifically, the array data showing the change in the amplitude value according to the distance) obtained in the Nth detection is referred to as Data [N] or the like. .. Further, the data that is the source of the interpolated video in the echo signal acquired region is referred to as DisplayData1 or the like. As shown in FIG. 4, it is indicated by DisplayData1 = α · Data [N] + β · Data [N-1]. Here, α and β are weighting coefficients when convexly combining the data of the two echo signals. In the present embodiment, α and β are sequence data whose values change in the distance direction, and the values change with the passage of time.

The weighting coefficient determining line shown in FIG. 4 is a straight line used when obtaining α and β. The weighting coefficient determination line is inclined so as to approach the lower side (old echo signal side) as it approaches the right side (the side farther from the ship). Here, in the distance A of the echo signal acquired region, "distance from the weighting coefficient determining line to the echo signal [N-1]": "distance from the weighting coefficient determining line to the echo signal [N]" is L1: L2. Suppose that In this case, α and β are determined so that α: β = L1: L2. Specifically, since α + β = 1, α = L1 / (L1 + L2) and β = L2 / (L1 + L2). As described above, the weighting coefficients α and β are obtained.

In this way, the echo signal closer to the weighting coefficient determination line is preferentially used (the value of the weighting coefficient is increased). Therefore, considering the inclination of the weighting coefficient determination line, the newly acquired echo signal (echo signal [N] in FIG. 4) is preferentially used to generate the interpolated image as it gets closer to the ship. .. The same applies to α and β in the region where the echo signal has not been acquired, except that the echo signal is one old.

When time elapses from the state shown in FIG. 4, the arrow of the echo signal [N] extends to the right and the weighting coefficient determining line moves upward. After that, when all the echo signals up to the set distance R have been acquired for the echo signal [N], the ultrasonic wave in the next detection is transmitted, and the echo signal [N + 1] starts to be acquired. FIG. 5 shows the state after the echo signal [N + 1] is acquired. As shown in FIG. 5, when the next echo signal [N + 1] starts to be acquired, the echo signals used for calculating DisplayData1 and DisplayData2 are updated one by one.

As described above, in the present embodiment, immediately after a new echo signal is acquired at a predetermined point, the weight of the echo signal is 0, and the weight of the previous echo signal is 1. That is, at this point, only one of the two echo signals is used. However, even at this point, only one echo signal is used as a result of adjusting the weights of the two echo signals, and further, at a point slightly away from this point, both of the two echo signals are used. It is used. Therefore, even if a point where only one of the two echo signals is used is included in this way, it is treated as corresponding to the interpolated image. At this point, the weight of the new echo signal changes from 0 to 1 over the time of one cycle of the ultrasonic transmission cycle (at the same time, the weight of the previous echo signal changes from 1 to 0). ).

As described above, the image generation unit 32 calculates the data that is the source of the interpolated image for each of the echo signal acquired area and the echo signal unacquired area. The data calculated here is data showing a change in the amplitude value according to the distance in a predetermined direction. Further, the image generation unit 32 performs a process of calculating this data for all the detected directions, and calculates the data that is the source of the interpolated image for each direction. As a result, the data that is the source of the interpolated video can be calculated for all the detected areas. That is, the above-mentioned DisplayData and Data are variables of a two-dimensional array. Further, the image generation unit 32 can generate an interpolated image by adding parameters such as drawing color or brightness according to the amplitude value of the data. The image generation unit 32 generates a complementary image a plurality of times using the echo signal obtained by one detection. The frequency of generation of the interpolated video is arbitrary and can be set, but it is preferable to generate the interpolated video 10 to 30 times per second because the underwater detection video switches smoothly as the frequency of generation of the interpolated video increases.

Next, the display of the generated interpolated video will be described while comparing with a conventional example. In the following, when the echo indicating the school of fish included in the underwater detection image is moving, the changes in the underwater detection image of the conventional example and the present embodiment will be compared and described. Further, in the following description, the echo image showing the detection result obtained from the echo signal [N] is referred to as an echo image [N] or the like, and two echo images obtained from the echo signal [N-1] and the echo signal [N], respectively. Interpolated video that interpolates the detection result is called an interpolated video [N-1, N] or the like.

FIG. 6 shows a change in the echo indicating the school of fish displayed on the display unit in the conventional example. Consider the case where the school of fish (echo of the school of fish) moves to the left as shown in the upper left of FIG. In the conventional example, only the echo image [N-1] and the echo image [N] are generated, and the interpolated image is not generated. Further, as the echo signal obtained by the Nth detection is acquired, the echo image [N-1] is switched to the echo image [N] in the order of the distance from the own ship. Therefore, as shown in FIG. 6, the underwater detection image has a break, which may make it difficult to confirm the size and shape of the echo. The user may also be fascinated by the change in the break, making it difficult to focus on checking the echo.

FIG. 7 shows a change in the echo indicating the school of fish displayed on the display unit 17 in the present embodiment. The movement of the school of fish (echo of the school of fish) is the same as in FIG. In FIG. 7, the magnitude of the echo amplitude value is represented by the dot density (the larger the amplitude value, the higher the dot density).

In the present embodiment, the image generation unit 32 generates an interpolated image [N-1, N] that interpolates the echo image [N-1] and the echo image [N]. Then, the display control unit 33 switches the interpolated video. Specifically, the image generation unit 32 interpolates the echo image [N-2] and the echo image [N-1] in the region before acquiring the echo signal by the Nth detection, and the interpolated image [N-]. 2, N-1] is generated. Further, the image generation unit 32 generates an interpolated image [N-1, N] that interpolates the echo image [N-1] and the echo image [N] in the region where the echo signal obtained by the Nth detection has been acquired. To do. As described with reference to FIGS. 4 and 5, the interpolated video is generated over time by preferentially using the newer echo signal (ie, increasing the weighting factor). Therefore, also in FIG. 7, the interpolated image [N-2, N-1] approaches the amplitude value of the echo signal [N-1] from the amplitude value of the echo signal [N-2] with the passage of time. Changes to. Further, the interpolated video [N-1, N] changes from the amplitude value of the echo signal [N-1] to approach the amplitude value of the echo signal [N] with the passage of time. Further, as described above, the switching of the interpolated image is performed from the side close to the own ship. Therefore, also in FIG. 7, the interpolated image is switched from the interpolated image [N-2, N-1] to the interpolated image [N-1, N] in order from the lower side.

As shown in FIG. 7, in the present embodiment, the underwater detection image is smoothly switched. Therefore, since the breaks in the image do not occur or are unlikely to occur, it is possible to easily confirm the underwater detection image. As a result, it becomes easy to confirm the shape and size of the echo of interest. In addition, since the image is less likely to be cut, the user can concentrate on checking the echo. In FIG. 7, the amount of movement of the echo indicating the school of fish was increased in order to explain the change in the image in an easy-to-understand manner. However, in reality, the echo indicating the school of fish does not move much in one transmission cycle. In some situations, it is possible to allow the echoes that indicate the school of fish to move while maintaining the echo shape.

As described above, the underwater detection signal processing device 11 of the present embodiment includes a storage unit 22, a video generation unit 32, and a display control unit 33. The storage unit 22 stores an echo signal which is a reflected wave of ultrasonic waves continuously transmitted in a predetermined range in water. The image generation unit 32 reads the echo signal obtained by two or more consecutive detections from the storage unit 22, and uses the echo signal obtained by two or more consecutive detections to use the weighting coefficient of the new echo signal. Is increased with the passage of time to generate an interpolated image. The display control unit 33 controls to display the interpolated video generated by the video generation unit 32.

As a result, the underwater detection image is smoothly switched by using the interpolated image. Therefore, since the breaks in the image do not occur or are unlikely to occur, it is possible to easily confirm the underwater detection image. As a result, it becomes easy to confirm the shape and size of the echo of interest.

Further, in the underwater detection signal processing device 11 of the present embodiment, when the echo signal up to the middle of the detection distance is obtained in the Nth detection, the echo signal [N] has been acquired in the distance range (echo signal acquisition). In the completed region), as the distance from the own machine becomes closer, the weighting coefficient of the echo signal [N] is made larger than that of the echo signal [N-1] to generate an interpolated image. In the distance range in which the echo signal [N] has not yet been acquired (the region in which the echo signal has not been acquired), the echo signal [N-1] becomes more pronounced than the echo signal [N-2] as the distance from the aircraft becomes closer. An interpolated image is generated by increasing the weighting coefficient.

Generally, the time taken from transmitting an ultrasonic wave to receiving an echo signal depends on the distance from the own aircraft to the target. Therefore, as described above, the Nth echo can be used at an earlier timing by changing the timing of using the Nth echo according to the distance from the own machine.

Further, in the underwater detection signal processing device 11 of the present embodiment, an interpolated image is generated by using only the echo signal [N-1] and the echo signal [N] in the distance range in which the echo signal [N] has been acquired. To do. In the distance range in which the echo signal [N] has not been acquired yet, the interpolated image is generated by using only the echo signal [N-2] and the echo signal [N-1].

In this way, by generating the interpolated image based on only two echo signals among the echo signals, the process of creating the interpolated image can be simplified as compared with the configuration using three or more echo signals. Can be done.

Although the preferred embodiment of the present invention has been described above, the above configuration can be changed as follows, for example.

In the above embodiment, the movement and turning of the ship are not mentioned, but it is preferable to generate the underwater detection image (echo image, interpolated image) in consideration of them. For example, if the ship has moved before the echo signal is acquired, it is preferable to correct the amount of movement. Further, when the ship turns before the echo signal is acquired, it is preferable to acquire the turning angle of the ship by a directional sensor or the like and extract the echo signal to be referred to according to the turning angle.

In the above embodiment, the interpolated image is generated by using the echo signal obtained by two consecutive detections, but the echo signal obtained by more detections (for example, three or four consecutive detections) is generated. It may be used to generate an interpolated image.

In the above embodiment, the data that is the source of the interpolated image is calculated from the echo signal obtained by two consecutive detections using the convex combination, but two or more consecutive times using a method other than the convex combination. The data that is the source of the interpolated image may be calculated from the echo signal obtained by the detection of. Further, the process of performing the convex combination can be realized by, for example, a filter process using an FIR digital filter. Further, a process of calculating the data that is the source of the interpolated image from the echo signal obtained in the past by a method other than the convex combination can be realized by using, for example, an IIR filter.

In the above embodiment, the weighting coefficient determining line is a straight line, but at least a part of the line may include a curve. By adjusting the weight coefficient determination line in this way, a desired interpolated image can be generated by changing the coefficient (weight) of the convex combination according to the situation and the request.

In the above embodiment, the transmitter / receiver 14 has a cylindrical housing, but other shapes (for example, a sphere) may be used. Further, the oscillator of the transmitter / receiver 14 performs both transmission and reception of ultrasonic waves, but different oscillators may be used for transmission and reception. In this case, a device that combines a transmitting oscillator and a receiving oscillator corresponds to a transmitter / receiver (the transmitting oscillator and the receiving oscillator may be arranged at separate positions).

In the above embodiment, an image generated by using the echo signal obtained by one detection and using no other echo signal other than noise removal is referred to as an echo image, and is obtained by a plurality of detections. An image that interpolates an echo image using the generated echo signal is called an interpolated image. Then, an interpolated image is displayed between the echo image and the next echo image. Instead of this, the configuration may be such that only the interpolated image is continuously displayed without displaying the echo image (that is, the weighting coefficient is changed so that the weighting coefficient does not become 0).

In the above embodiment, as shown in FIG. 4, the echo signal [N] and the echo signal [N-1] are used in all the echo signal acquired regions to calculate the data that is the source of the interpolated image. Instead of this configuration, in consideration of processing delay or other circumstances, the echo signal [N-1] and the echo signal [N-2] are used in a part of the echo signal acquired area to generate the interpolated image. Data may be calculated.

In the above embodiment, in the Nth detection, the generation of the interpolated image using the echo signal [N] is started from the echo signal acquired region. In other words, the underwater detection images are switched in order from the side closest to the ship. Instead of this configuration, the underwater detection image may be switched at the same timing regardless of the distance from the own ship. In this case, after the Nth detection is completed (after all the echo signals [N] have been acquired), the interpolated video [N-1, N] is based on the echo video [N-1] and the echo video [N]. Is generated, so the real-time property is reduced, but the underwater detection image can be switched more smoothly.

In the above embodiment, the elevation / depression direction is constant and a predetermined range in the azimuth direction is detected. It may be configured.

10 Underwater detection device 11 Underwater detection signal processing device 12 Transmission circuit 13 Transmission / reception switch 14 Transmission / reception device 15 Reception circuit 16 A / D converter 17 Display unit 18 Operation unit 21 Calculation unit 22 Storage unit 31 Transmission control unit 32 Video generation unit 33 Display control unit

Claims (4)

A storage unit that stores an echo signal, which is a reflected wave of ultrasonic waves continuously transmitted to a predetermined range in water,
An image generation unit that reads out an echo signal obtained by two or more consecutive detections from the storage unit and generates an interpolated image using the echo signal obtained by the two or more consecutive detections.
A display control unit that controls the display of the interpolated video generated by the video generation unit, and
Equipped with a,
Generally, when the echo signal at the time of the kth detection is expressed as the echo signal [k],
The video generator
When the echo signal up to the middle of the detection distance is obtained in the Nth detection,
In the distance range in which the echo signal [N] has been acquired, the weighting coefficient of the echo signal [N] is made larger than that of the echo signal [N-1] as the distance from the own machine becomes closer. Generate an interpolated image,
In the distance range in which the echo signal [N] has not been acquired yet, the weighting coefficient of the echo signal [N-1] is increased as the distance from the own machine becomes closer than that of the echo signal [N-2]. An underwater detection signal processing device, which is characterized by generating the interpolated image . The underwater detection signal processing device according to claim 1 .
The video generator
In the distance range in which the echo signal [N] has been acquired, the interpolated image is generated by using only the echo signal [N-1] and the echo signal [N].
In the distance range in which the echo signal [N] has not been acquired yet, the underwater detection signal is characterized in that the interpolated image is generated by using only the echo signal [N-2] and the echo signal [N-1]. Processing equipment. The underwater detection signal processing device according to claim 1 or 2 .
A transmitter / receiver that transmits ultrasonic waves to a predetermined range in water, receives reflected waves of the ultrasonic waves, and outputs them to the underwater detection signal processing device.
A display unit that displays the interpolated image generated by the underwater detection signal processing device, and
An underwater detector characterized by being equipped with. An ultrasonic wave is transmitted to a predetermined range in water using an underwater detector , and an echo signal, which is a reflected wave of the ultrasonic wave, is acquired.
It generates Interpolation image using an echo signal obtained by the detection least two consecutive of
In line Cormorant detection signal processing method of water control to display the interpolated image,
Generally, when the echo signal at the time of the kth detection is expressed as the echo signal [k],
In generating the interpolated video,
When the echo signal up to the middle of the detection distance is obtained in the Nth detection,
In the distance range in which the echo signal [N] has been acquired, the weighting coefficient of the echo signal [N] is made larger than that of the echo signal [N-1] as the distance from the underwater detector becomes closer. , Generate the interpolated video,
In the distance range in which the echo signal [N] has not been acquired yet, the weighting coefficient of the echo signal [N-1] is increased more than that of the echo signal [N-2] as the distance from the underwater detector becomes closer. An underwater detection signal processing method characterized in that the interpolated image is generated by increasing the size .

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