Fish finder, image generation method, and program

Abstract

To provide a fish detection device that displays an image allowing a determination as to whether a plurality of types of fish are included in a school of fish, an image creation method, and a program.SOLUTION: A fish detection device 100 comprises: a receiving circuit 104 that generates echo data indicating echo intensity at every depth on the basis of a received signal of ultrasonic waves transmitted in a depth direction; and a signal processing circuit 101 that processes the echo data to create an image. The signal processing circuit 101 creates an echo image in which the echo intensities are distributed in a coordinate area with the depth and time as two axes on the basis of the echo data, divides a measuring range of a school of fish set in the echo image into a plurality of sections, calculates index values of fish species for each of the sections on the basis of the echo data, and superimposes an index image of the school of fish based on the index values on the measuring range.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a fish school detection device for detecting a fish school in water, an image generation method for processing echo data to generate an image, and a program for causing a computer to execute a function of processing echo data to generate an image.

Background Art

[0002] Conventionally, a fish school detection device for detecting a fish school in water has been known. In this type of fish school detection device, ultrasonic waves are transmitted into water, and the reflected waves are received. Echo data corresponding to the intensity of the received reflected waves is generated, and an echo image is displayed based on the generated echo data. In the echo image, the intensity distribution of the reflected waves at each water depth is displayed by colors of corresponding gradations. A fish school detection device having such a configuration is described in, for example, Patent Document 1 below.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the fish school detection device having the above configuration, the position and range of the fish school in water can be grasped by referring to the echo image. However, it is difficult to immediately determine whether the displayed fish school is composed of a single fish species or not from the echo image. In particular, depending on the display sensitivity, the echoes of fish of different fish species may be displayed in substantially the same gradation. For this reason, there are cases where the fish school included in the echo image appears to be composed of a single fish species. However, in such a case, if this fish school is captured by a fishing net or the like and as a result, fish of a plurality of fish species are mixed, the fishing result becomes a so-called mixture, and the fish price decreases.

[0005] In view of these problems, the present invention aims to provide a fish finder, an image generation method, and a program that can display an image capable of determining whether or not multiple types of fish are mixed in a school of fish. [Means for solving the problem]

[0006] A first aspect of the present invention relates to a fish finder. The fish finder according to this aspect includes a receiving circuit that generates echo data indicating the echo intensity for each depth based on the received signal of ultrasonic waves transmitted in the depth direction, and a signal processing circuit that processes the echo data to generate an image. The signal processing circuit generates an echo image in which the echo intensity is distributed in a coordinate region with depth and time as two axes based on the echo data, and sets the measurement range of the fish school set in the echo image. , in the direction of the two axes, Divided into multiple sections, based on the echo data Estimate the number of individual fish included in the aforementioned measurement range, Each of the above sections The value relating to the density of the individual fish Indicator values ​​for fish species as The index value is calculated, and an index image of the fish school based on that index value is superimposed onto the measurement range.

[0007] According to the fish finder device of this embodiment, an indicator image of the fish school is superimposed on the measurement range of the fish school on the echo image. Therefore, the user can determine from the indicator image whether or not multiple types of fish are mixed in the fish school within the measurement range. Thus, the user can smoothly decide whether or not to capture this fish school.

[0009] The density of fish schools can vary depending on the fish species. For example, sardines form denser schools than mackerel. With the above configuration, an index image is created for each section, using a value related to the density of individual fish as the index value. Therefore, the user can understand the differences in fish density between sections from the index image and determine whether or not multiple types of fish are mixed in the fish school within the measurement range.

[0010] In this case, the density value may be the number of individual fish contained in the section. Alternatively, the density value may be the ratio of the number of individual fish contained in the section to the number of individual fish contained in the measurement range.

[0011] Furthermore, the fish finder according to this embodiment The system comprises a receiving circuit that generates echo data indicating the echo intensity for each depth based on received signals of first and second frequency ultrasound transmitted in the depth direction, and a signal processing circuit that processes the echo data to generate an image. The signal processing circuit generates an echo image in which the echo intensity is distributed in a coordinate region with depth and time as two axes, from the echo data based on either the first or second frequency ultrasound, divides the measurement range of the fish school set in the echo image into a plurality of sections in the direction of the two axes, calculates the difference between the echo intensity based on the first frequency ultrasound and the echo intensity based on the second frequency ultrasound as an index value for the fish species for each section, and superimposes an index image of the fish school based on the index value onto the measurement range. It may be configured in such a way.

[0012] Different fish species may have different reflection characteristics at different frequencies. For example, fish with swim bladder and fish without swim bladder have different reflection characteristics at different frequencies. In the above configuration, an index image is created for each section using the difference between the echo intensity based on the first frequency ultrasound and the echo intensity based on the second frequency ultrasound as the index value. Therefore, the user can understand the differences in fish species between sections from the index image, and thereby determine whether or not multiple types of fish are mixed in the school of fish within the measurement range.

[0013] In the fish finder according to this embodiment, the indicator image may be an image in which each of the sections is colored according to the magnitude of the indicator value of each section.

[0014] With this configuration, users can intuitively understand the differences in fish species between sections based on the colors assigned to each section.

[0015] Alternatively, the index image may be an image showing the boundaries of each group when the sections are grouped according to the magnitude of the index value.

[0016] In this case, the user can understand that there may be differences in fish species between groups separated by boundaries. Then, by referring to the echo images included in the range of each group, the user can understand the echo intensity of each group and determine the similarities or differences in fish species between the groups based on the differences in echo intensity between the groups. In this case, for example, by adjusting the display sensitivity of the echo images, the user can more easily confirm the similarities or differences in echo intensity of the echo images included in the range of each group. Thus, with the above configuration, it is possible to smoothly determine whether or not multiple fish species are included in the measurement range while using the original echo images.

[0017] A second aspect of the present invention relates to an image generation method for generating an image by processing echo data indicating the echo intensity for each depth, which is generated from the received signal of ultrasonic waves transmitted in the depth direction. The image generation method according to this aspect comprises the steps of generating an echo image in which the echo intensity is distributed in a coordinate region with depth and time as two axes based on the echo data, and setting the measurement range of the fish school in the echo image. , in the direction of the two axes, The process of dividing into multiple sections and based on the echo data A step of estimating the number of individual fish included in the measurement range, Each of the above sections The value relating to the density of the individual fish Indicator values ​​for fish species as The process includes a calculation step and a step of superimposing an indicator image of a school of fish based on the indicator value onto the measurement range.

[0018] According to the image display method of this embodiment, similar to the first embodiment described above, an indicator image of the fish school is superimposed on the measurement range of the fish school on the echo image. Therefore, the user can determine from the indicator image whether or not multiple types of fish are mixed in the fish school within the measurement range. Thus, the user can smoothly decide whether or not to capture this fish school.

[0019] A third aspect of the present invention relates to a program that causes a computer to execute a function of generating an image by processing echo data indicating echo intensity for each depth generated from a reception signal of ultrasonic waves transmitted in the depth direction. The program according to this aspect causes the computer to generate an echo image in which the echo intensity is distributed in a coordinate region having depth and time as two axes based on the echo data, and the measurement range of the fish school set in the echo image is , in the direction of the two axes, a function of dividing into a plurality of sections, and based on the echo data A function to estimate the number of individual fish included in the aforementioned measurement range, for each of the sections The value relating to the density of the individual fish a function of calculating an index value of the fish species as and a function of superimposing an index image of the fish school based on the index value on the measurement range.

[0020] According to the program according to this aspect, similar to the first aspect, an index image of the fish school is superimposed on the measurement range of the fish school on the echo image. Therefore, the user can determine from the index image whether a plurality of types of fish are mixed in the fish school in the measurement range. Thus, the user can smoothly determine whether or not to catch this fish school.

Effects of the Invention

[0021] As described above, according to the present invention, it is possible to provide a fish school detection device, an image generation method, and a program that display an image capable of determining whether a plurality of types of fish are mixed in a fish school.

[0022] The effects or significance of the present invention will become clearer from the description of the embodiments shown below. However, the embodiments shown below are merely examples when implementing the present invention, and the present invention is not limited to those described in the following embodiments.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 is a diagram showing a usage form of a fish school detection device according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing a configuration of a fish school detection device according to an embodiment. [Figure 3] Figure 3(a) is a flowchart of the image generation process according to the embodiment. Figure 3(b) is a flowchart of the index image superposition process according to the embodiment. [Figure 4] Figure 4(a) is a flowchart showing the index value calculation process according to the embodiment. Figure 4(b) is a flowchart showing the index image generation process according to the embodiment. [Figure 5] Figure 5 shows an example of an echo image display according to the embodiment. [Figure 6] Figure 6 shows a state in which a measurement range has been set on the echo image according to the embodiment. [Figure 7] Figure 7 shows a state in which the measurement range set in the echo image is divided into multiple sections, according to the embodiment. [Figure 8] Figure 8 shows a state in which an index image is superimposed on the measurement range set on the echo image, according to the embodiment. [Figure 9] Figures 9(a) to 9(c) show, respectively, the index images when three different color scales are applied according to the embodiment. [Figure 10] Figures 10(a) and 10(b) show the index images when other color scales are applied according to the embodiment, respectively. [Figure 11] Figure 11(a) is a flowchart showing the process for generating the indicator image related to Modification Example 1. Figures 11(b) to 11(d) show the steps for generating the indicator image related to Modification Example 1. [Figure 12] Figure 12 shows the state in which the index image is superimposed on the measurement range of the echo image, according to modification example 2. [Figure 13] Figure 13 shows an echo image with the index image superimposed when the display sensitivity is adjusted, according to modification example 2. [Figure 14] Figure 14 shows another example of the configuration of the indicator image related to modification example 2. [Figure 15] Figure 15 is a block diagram showing the configuration of the fish finder device according to modification example 2. [Figure 16] Figure 16 is a flowchart showing the calculation process for the indicator value related to Change Example 2. [Modes for carrying out the invention]

[0024] Embodiments of the present invention will be described below with reference to the drawings.

[0025] Figure 1 shows the usage configuration of the fish finder according to this embodiment.

[0026] In this embodiment, a transducer 2 is installed on the bottom of the ship 1, and an ultrasonic transmitting beam 3 is transmitted into the water from the transducer 2. The transmitting beam 3 has a conical shape with a small apex angle and is transmitted in a pulsed manner in the vertically downward direction. The transmitting beam 3 is reflected by the seabed 4 and schools of fish 5, and the reflected waves (echoes) are received by the transducer 2. Based on the received signal of the reflected waves from a single transmission of the transmitting beam 3, echo data is generated in which the signal strength (echo strength) of the received signal is distributed in the detection range in the water depth direction.

[0027] As echo data for a predetermined period of time is accumulated, an echo image is generated that shows the distribution of signal intensity (echo intensity) in the direction of water depth. The echo image includes the intensity distribution of targets. The generated underwater echo image is displayed on a monitor or other display unit installed in the wheelhouse or other location on the ship 1. This allows the user to identify targets (such as the seabed 4 or schools of fish 5) present in the water.

[0028] Figure 2 is a block diagram showing the configuration of the fish finder device 100.

[0029] The fish finder device 100 includes, in addition to the transducer 2 shown in Figure 1, a signal processing circuit 101, a memory 102, a transmission circuit 103, a reception circuit 104, a switching circuit 105, an input unit 106, and a display unit 107.

[0030] The signal processing circuit 101, memory 102, transmission circuit 103, reception circuit 104, switching circuit 105, input unit 106, and display unit 107 are installed in the wheelhouse or other location of the ship 1. The components excluding the transducer 2 may be unitized in a single housing, or some components such as the display unit 107 may be separate units. The switching circuit 105 is connected to the transducer 2 via a signal cable in a communicative manner.

[0031] The transducer 2 comprises a transmitter used for transmitting ultrasonic waves and a receiver used for receiving ultrasonic waves. In this embodiment, the transmitter and receiver of the transducer 2 are composed of a single ultrasonic transducer 21.

[0032] The transmitting circuit 103, under control from the signal processing circuit 101, outputs a transmission signal of a predetermined frequency to the ultrasonic transducer 21 of the transducer 2 via the switching circuit 105. The ultrasonic transducer 21 transmits ultrasonic waves (transmitting beam 3) into the water based on the transmission signal. The ultrasonic transducer 21 also receives the reflected waves of the transmitted ultrasonic waves and outputs a received signal of a magnitude corresponding to the intensity of the reflected waves to the receiving circuit 104 via the switching circuit 105. The switching circuit 105 switches between transmitting and receiving signals to the ultrasonic transducer 21.

[0033] The receiving circuit 104 generates echo data indicating the echo intensity for each depth based on the signal received from the ultrasonic transducer 21. Specifically, the receiving circuit 104 generates echo data that associates the elapsed time since the ultrasonic wave (transmitting beam 3) was transmitted with the intensity of the reflected wave, and outputs the generated echo data to the signal processing circuit 101. Here, the elapsed time since the ultrasonic wave was transmitted corresponds to the depth. Note that the intensity of the reflected wave attenuates as the depth increases. Therefore, the receiving circuit 104 corrects the intensity of the reflected wave that attenuates according to the elapsed time, and outputs the echo data with the corrected intensity to the signal processing circuit 101.

[0034] The signal processing circuit 101 is composed of arithmetic processing circuits such as a CPU and integrated circuits such as an FPGA. The memory 102 is composed of ROM, RAM, hard disk, etc. Various programs are stored in the memory 102. These programs include programs that cause the signal processing circuit 101 (computer) to execute the function of processing echo data and generating an image. The memory 102 is also used as a work area during processing by the signal processing circuit 101. The signal processing circuit 101 controls each part according to the programs stored in the memory 102. The process of processing echo data and generating an image will be explained with reference to Figures 3(a), (b) and 4(a), (b).

[0035] The input unit 106 is comprised of input means such as a mouse or keyboard and accepts input from the user. The input unit 106 may be a touch panel integrated with the display unit 107. The display unit 107 is comprised of a display device such as a CRT monitor or liquid crystal panel and displays an image generated by the signal processing circuit 101. As described later, the display unit 107 displays an echo image generated based on echo data.

[0036] The signal processing circuit 101 acquires echo data that associates depth with echo intensity for each ultrasonic wave (transmit beam 3) transmission (each ping). Based on the continuously acquired echo data for one frame (multiple pings), the signal processing circuit 101 generates an echo image and displays it on the display unit 107. The echo image is sometimes called an echo diagram. The echo image is an image in which the echo intensity is distributed in a coordinate region with depth and time as two axes. In the echo image, each pixel is colored or shaded according to the intensity of the reflected wave (echo intensity).

[0037] Users such as fishermen can understand the location and extent of a school of fish in the water by referring to the echo image displayed on the display unit 107. However, it is difficult for users to immediately determine whether the school of fish included in the echo image consists of a single species or not. In particular, depending on the display sensitivity, echoes of different fish species may be displayed with almost the same gradation. As a result, the school of fish included in the echo image may appear to consist of a single species. In such cases, if a user catches this school of fish using a cast net or the like, and it turns out that multiple species of fish are mixed together, the catch will be considered a mixture, and the fish price will decrease.

[0038] Therefore, in this embodiment, an indicator image capable of determining whether or not multiple types of fish are mixed in a school of fish is displayed superimposed on the echo image. The process for generating such an image will be described below.

[0039] Figure 3(a) is a flowchart showing the image generation process.

[0040] The signal processing circuit 101 processes one frame of echo data held in memory 102, that is, echo data from the current time to a predetermined time prior, to generate an echo image, and displays the generated echo image on the display unit 107 (S101). Next, the signal processing circuit 101 determines whether or not a measurement range has been set on the echo image via the input unit 106 (S102). The user sets a measurement range for the desired school of fish displayed on the echo image. Here, the measurement range is set as a rectangular area using a mouse or the like. The user can set the measurement range to a desired size in the depth direction and the time direction.

[0041] If the user does not set a measurement range (S102: NO), the signal processing circuit 101 repeats the process in step S101. This updates the echo image to the latest time as it is received. On the other hand, if the user sets a measurement range (S102: YES), the signal processing circuit 101 performs indicator image superposition processing (S103). This superimposes an indicator image, which can be used as an indicator for identifying fish species, onto the measurement range set by the user.

[0042] The signal processing circuit 101 repeatedly executes the processes from step S101 onward until the image display processing is completed (S104:NO). As a result, the echo image with the indicator image superimposed on the position of the school of fish is updated in real time and displayed on the display unit 107. The superimposition of the indicator image may be removed by user operation, or it may be removed automatically after a predetermined time has elapsed.

[0043] Figure 3(b) is a flowchart showing the index image superposition process in step S103 of Figure 3(a).

[0044] The signal processing circuit 101 divides the measurement range into multiple grid sections (S111). The size of each section may be predetermined. In this case, the user can set a measurement range that is an integer multiple of the depth length of one section and an integer multiple of the time length of one section. Alternatively, the measurement range may be divided into a predetermined number of sections in both the depth and time directions, and each section may be set accordingly. In this case, the user can set a measurement range of any size, and the size of each section will change according to the size of the measurement range set by the user.

[0045] Next, the signal processing circuit 101 calculates an index value for each fish species in each section based on the echo data (S112). Furthermore, the signal processing circuit 101 generates an index image of the fish school based on the index value of each section (S113). Then, the signal processing circuit 101 superimposes the generated index image onto the measurement range on the echo image (S114).

[0046] Figure 4(a) is a flowchart showing the calculation process of the index value in step S112 of Figure 3(b).

[0047] In this embodiment, a value relating to the density of individual fish contained in each section is obtained as an index value for each section. Here, the density value is, for example, the number of individual fish contained in each section. Alternatively, the density value may be the ratio of the number of individual fish contained in each section to the total number of individual fish contained in the measurement range.

[0048] First, the signal processing circuit 101 performs a process to estimate individual fish included in the measurement range based on the echo data within the measurement range (S121). Specifically, the signal processing circuit 101 detects a region where the echo intensity is equal to or greater than a threshold for target detection, and if the width of this region is less than or equal to a threshold for individual fish discrimination, it estimates this region as an individual fish. However, the method for estimating individual fish based on echo data is not limited to this, and other conventionally known methods may be used.

[0049] Next, the signal processing circuit 101 calculates an index value for the density of individual fish in each section based on the estimated individual fish (S122). Specifically, the signal processing circuit 101 counts the individual fish estimated in step S121 for each section and obtains the counted number as the number of individual fish contained in each section. The signal processing circuit 101 then obtains the obtained number of individual fish in each section as an index value for the density of individual fish in each section. Alternatively, the signal processing circuit 101 may obtain the ratio of the number of individual fish contained in each section to the number of individual fish contained in the measurement range as an index value for the density of individual fish in each section.

[0050] Figure 4(b) is a flowchart showing the process of generating the index image in step S113 of Figure 3(b).

[0051] The signal processing circuit 101 sets a color for each section according to the index value of each section, according to a preset scale (S131). Then, the signal processing circuit 101 generates an index image by assigning the set color to each section (S132).

[0052] Next, we will explain the process by which the index image is superimposed on the echo image through the processing shown in Figures 3(b) and 4(a) and (b).

[0053] Figure 5 shows the state in step S101 of Figure 3(a) where the echo image P1 is displayed.

[0054] The echo image P1 is constructed by distributing echo intensity across a coordinate region with two axes: the horizontal axis represents time and the vertical axis represents depth. On the horizontal axis, the rightmost point is the current time, and the time increases as you move to the left. On the vertical axis, the top point is zero depth, and the depth increases as you move downwards. The rightmost column distributes the echo intensity at each depth acquired by the current transmission and reception. The echo intensity of coordinate points on the echo image P1 is colored according to a predetermined color scale.

[0055] For example, a color scale is used in which red is applied to the highest tone echo intensity, blue to the lowest tone echo intensity, and yellow to the intermediate tone echo intensity, with the colors between these colors transitioning according to the echo intensity. Here, for convenience, the echo image is represented on a black and white color scale, with colors closer to black as the echo intensity increases and colors closer to white as the echo intensity decreases.

[0056] For this echo image P1, for example, as shown in Figure 6, a measurement range 200 is set by user operation. The user sets the measurement range 200 to the position of the school of fish on the echo image P1.

[0057] Once the measurement range 200 is set, in step S111 of Figure 3(b), the measurement range 200 is divided into multiple sections 201 in a grid pattern, as shown in Figure 7. Furthermore, in step S112 of Figure 3(b), an index value is calculated for each section 201. The index value for each section is calculated by the process shown in Figure 4(a).

[0058] In step S113 of Figure 3(b), an index image is generated from the index values ​​of each section 201. The index image is generated by the process shown in Figure 4(b). In step S114 of Figure 3(b), the index image 202 is superimposed on the echo image P1, as shown in Figure 8. As a result, the index image 202 is superimposed and displayed within the measurement range 200 set by the user.

[0059] In Figure 8, the index image 202 is an image in which each section 201 is colored according to the magnitude of the index value of each section 201. For convenience, in Figure 8, the color of each section 201 is shown by the intensity of hatching. The index value of each section 201 may be represented in a form other than color. For example, the index value of each section 201 may be displayed by the intensity of hatching, or it may be represented by a scale with the same color but different brightness levels.

[0060] By referring to the indicator image 202 in Figure 8, the user can determine whether or not multiple fish species exist within the measurement range 200.

[0061] In other words, the density of fish schools can differ depending on the fish species. For example, sardines form schools at a higher density than mackerel. Therefore, as in this embodiment, if indicator images 202 with different colors are configured for each section 201 using a value related to the density of individual fish as an indicator value, the user can grasp the differences in fish density between sections 201 from the indicator images 202 and determine whether or not multiple types of fish are mixed in the fish school within the measurement range 200.

[0062] Figures 9(a) to 9(c) show the index image 202 when three different color scales are applied. Here, the index value is defined as the number of individual fish in each section 201. For convenience, the number of individual fish is indicated as the index value for each section 201 in Figures 9(a) to 9(c).

[0063] In Figure 9(a), the scale from the highest to the lowest color is applied uniformly to the range between the highest and lowest index values. That is, the highest index value is assigned the highest color (e.g., red), the lowest index value is assigned the lowest color (blue), and intermediate index values ​​between the highest and lowest index values ​​are assigned intermediate colors (e.g., yellow).

[0064] In Figure 9(b), the color scale is structured so that weights are assigned to the range of high index values. That is, in the color scale of Figure 9(b), as in Figure 9(a), the color with the highest gradation (e.g., red) is applied to the highest index value, and the color with the lowest gradation (blue) is applied to the lowest index value. However, unlike in Figure 9(a), the intermediate gradation color (e.g., yellow) is applied to index values ​​smaller than the intermediate index value.

[0065] In Figure 9(c), the color scale is structured so that weights are assigned to the lower range of index values. That is, in the color scale of Figure 9(c), as in Figure 9(a), the color with the highest gradation (e.g., red) is applied to the largest index value, and the color with the lowest gradation (blue) is applied to the smallest index value. However, unlike in Figure 9(a), the intermediate gradation color (e.g., yellow) is applied to index values ​​larger than the intermediate index value.

[0066] The color scales in Figures 9(a) to 9(c) are set so that the colors applied to the index value transition from the maximum gradation color through the intermediate gradation colors to the minimum gradation color as the index value decreases.

[0067] The user may switch and apply the scales shown in Figures 9(a) to 9(c) as needed to facilitate the smooth determination of whether a school of fish consists of a single species or not. Furthermore, when applying the scales in Figures 9(b) and 9(c), the user may also adjust the weights to the higher or lower weight side by changing the index values ​​to which intermediate grayscale colors are applied. This allows the user to smoothly determine whether a school of fish consists of a single species or not using their preferred color scale.

[0068] In Figures 9(a) to 9(c), the maximum gradation color is applied to the largest index value, and the minimum gradation color is applied to the smallest index value. However, the magnitudes of the index values ​​corresponding to the maximum gradation, minimum gradation, and intermediate gradation colors may be predetermined.

[0069] For example, a color scale may be used in which index values ​​of 80, 40, and 0 are associated with the maximum, minimum, and intermediate tones, respectively. In this case, all sections 201 with index values ​​exceeding 80 are uniformly assigned the maximum tone color. Alternatively, a color scale may be used in which index values ​​of 80, 50, and 20 are associated with the maximum, minimum, and intermediate tones, respectively. In this case, all sections 201 with index values ​​exceeding 80 are uniformly assigned the maximum tone color, and all sections 201 with index values ​​less than 20 are uniformly assigned the minimum tone color.

[0070] Figures 10(a) and 10(b) show the index image 202 when a color scale other than the one described above is applied. Here, the ratio of individual fish in each section 201 to the total number of individual fish included in the measurement range 200 is used as the index value for each section. For convenience, Figures 10(a) and (b) include the index value of the ratio of individual fish for each section 201.

[0071] In Figure 10(a), the maximum gradation color (e.g., red) is applied to a percentage of 10%, the minimum gradation color (blue) is applied to a percentage of 0%, and an intermediate gradation color (e.g., yellow) is applied to a percentage of 5%. Sections 201 with a percentage exceeding 10% are assigned the maximum gradation color. Sections within the range of 10% or less are assigned a color scale that transitions from the maximum gradation color through intermediate gradation colors to the minimum gradation color as the index value decreases.

[0072] In Figure 10(b), the maximum gradation color (e.g., red) is applied to the 20% percentage, the minimum gradation color (blue) is applied to the 0% percentage, and an intermediate gradation color (e.g., yellow) is applied to the 10% percentage. Sections 201 with a percentage exceeding 20% ​​are assigned the maximum gradation color. Sections within the 20% or less percentage range are assigned a color scale that transitions from the maximum gradation color through intermediate gradation colors to the minimum gradation color as the index value decreases.

[0073] In the color scale of Figure 10(b), the percentage value (index value) corresponding to the maximum gradation color is larger compared to the color scale of Figure 10(a), resulting in a smaller difference in color between the 201 sections.

[0074] In the cases of Figures 10(a) and 10(b), the user may appropriately switch and apply the scales shown in Figures 10(a) and 10(b) to facilitate the smooth determination of whether or not the school of fish consists of a single species. Furthermore, the user may arbitrarily adjust the index values ​​(percentages) corresponding to the maximum grayscale color, the minimum grayscale color, and the intermediate grayscale color. This allows the user to smoothly determine whether or not the school of fish consists of a single species using their preferred color scale.

[0075] <Effects of the Embodiment> According to this embodiment, the following effects are achieved.

[0076] As shown in Figure 8, the fish school indicator image 202 is superimposed on the measurement range 200 of the fish school on the echo image P1. Therefore, the user can determine from the indicator image 202 whether or not multiple types of fish are mixed in the fish school within the measurement range 200. Thus, the user can smoothly decide whether or not to capture this fish school.

[0077] As shown in Figure 4(a), the signal processing circuit 101 estimates individual fish included in the measurement range 200 based on echo data (S121), and calculates an index value for the density of individual fish for each section (S122). This allows the user to understand the differences in fish density between sections 201 from the index image 202, and to determine whether or not multiple fish species that form schools at different densities are mixed in the fish school within the measurement range 200.

[0078] In this case, the density value may be, for example, the number of individual fish contained in section 201, as shown in Figures 9(a) to 9(c). Alternatively, the density value may be, for example, the ratio of the number of individual fish contained in section 201 to the number of individual fish contained in the measurement range 200, as shown in Figures 10(a) and 10(b).

[0079] As explained with reference to Figures 8 and 9(a) to 10(b), the index image 202 may be an image in which each section 201 is colored according to the magnitude of the index value of each section 201. This allows the user to intuitively grasp the differences and similarities of fish species between sections 201 from the colors assigned to each section 201.

[0080] <Example of change 1> In the above embodiment, the indicator image 202 was constructed by assigning a color to each section 201 according to the indicator value of each section 201. However, the configuration of the indicator image is not limited to this, and the indicator image may be constructed in other forms as long as it is possible to determine the similarity or difference of fish species.

[0081] For example, the index image may be an image that shows the boundaries of each group when the section 201 is grouped according to the magnitude of the index value.

[0082] Figure 11(a) is a flowchart showing the process for generating the indicator image related to modification example 1.

[0083] The signal processing circuit 101 groups the sections 201 according to the magnitude of the index value (S141), and generates an image indicating the boundary between the groups as an index image (S142).

[0084] Figures 11(b) to 11(d) show an example of the specific processing steps S141 and S142 in Figure 11(a). Here, the number of individual fish in each section 201 is used as the index value. For convenience, the number of individual fish in each section 201 is noted in Figure 11(b).

[0085] The signal processing circuit 101 sets the section 201 with the smallest index value among all the sections 201 as the reference section. In the example in Figure 11(b), the section 201 in the lower right corner with a thick border is set as the reference section. Next, the signal processing circuit 101 calculates the multiplier of the index value of each section 201 relative to the index value of the reference section. In the example in Figure 11(b), the multiplier of each section 201 is the value attached to each section 201 in Figure 11(c). Here, the multiplier of the section 201 in the center of the top row is the largest.

[0086] The signal processing circuit 101 then groups the sections 201 at 50% of the maximum magnification. In the example in Figure 11(c), 50% of the maximum magnification is 2.1, so sections 201 with a magnification of 2.1 or higher are grouped together with sections 201 with a magnification less than 2.1. As a result, the sections 201 within the measurement range 200 are grouped together, as shown in Figure 11(c). In Figure 11(c), the group of sections with a magnification less than 2.1 is hatched.

[0087] After grouping the sections 201 in this way, the signal processing circuit 101 generates an image indicating the boundary between the groups as an index image. This generates an index image 203 that includes the boundary 203a as shown in Figure 11(d).

[0088] Figure 12 shows the state in which the index image 203 is superimposed on the measurement range 200 of the echo image P1.

[0089] In modification example 1, the measurement range 200 is not filled in, allowing the user to see the echo image in the background of the measurement range 200. By referring to the indicator image 203, the user can understand that there may be differences in fish species between the groups separated by the boundary 203a. Then, by referring to the echo images included in the range of each group, the user can understand the echo intensity of each group and determine the similarities or differences in fish species between the groups based on the differences in echo intensity between the groups.

[0090] In this case, the user can smoothly grasp the differences in echo intensity of echo images included in each group's range by adjusting the display sensitivity of the echo image P1, for example, as shown in Figure 13. Thus, according to modification example 1, it is possible to smoothly determine whether or not multiple fish species are included in the measurement range 200 while using the original echo image.

[0091] The method for grouping section 201 is not limited to the methods shown in Figures 11(b) to 11(d). For example, in the above example, section 201 was divided into two groups based on a magnification of 50% of the maximum magnification, but the criterion for grouping section 201 is not limited to 50% of the maximum magnification; for example, the user may specify it arbitrarily. Furthermore, this criterion does not have to be set in relation to the maximum magnification, and may be a fixed threshold. In this case, the user may arbitrarily adjust the fixed threshold.

[0092] Furthermore, in the processing shown in Figure 11(a), the image indicating the boundary between groups was used as the index image 203. However, as shown in Figure 14, for example, different display formats may be applied to the region of the group that is above a reference value (for example, 50% of the maximum magnification) and the region of the group that is below the reference value. For example, these two groups may be indicated by shades of color, or different colors may be assigned to the regions of these two groups.

[0093] Even when the indicator image 203 is configured in this way, the user can determine whether different fish species are included in the measurement range 200. In this case, the user may use the input unit 106 to appropriately erase the shading or color assigned to each group, displaying only the boundary 203a. This allows the user to further determine, as in Figures 12 and 13, whether there may be differences in fish species between groups based on the echo images in the background of each group's region.

[0094] <Example of change 2> In the above embodiment, a value relating to the density of individual fish was used as an indicator value for whether or not different fish species are included, but the indicator value is not limited to this. In modified example 2, the difference between the echo intensity based on first frequency ultrasound and the echo intensity based on second frequency ultrasound is used as the indicator value.

[0095] Figure 15 is a block diagram showing the configuration of the fish finder device 100 according to modification example 2.

[0096] In the modified example 2, the fish finder device 100 includes an ultrasonic transducer 22 in addition to the ultrasonic transducer 21. The ultrasonic transducer 21 transmits and receives ultrasonic waves at a first frequency (for example, 50 kHz), and the ultrasonic transducer 22 transmits and receives ultrasonic waves at a second frequency (for example, 200 kHz). The ultrasonic transducer 22 transmits ultrasonic waves in the same vertical downward direction as the ultrasonic transducer 21.

[0097] The fish finder 100 includes a transmitting circuit 111 for supplying a transmission signal to the ultrasonic transducer 22, a receiving circuit 112 for processing the received signal output from the ultrasonic transducer 22 to generate echo data, and a switching circuit 113 for switching between supplying a transmission signal to the ultrasonic transducer 22 and acquiring a received signal. The transmitting circuits 103 and 111 supply transmission signals of a first frequency and a second frequency to the ultrasonic transducers 21 and 22, respectively. The receiving circuits 104 and 112 each include filters for extracting a first frequency and a second frequency, respectively, and extract received signals having a first frequency and a second frequency from the signals output from the ultrasonic transducers 21 and 22 to generate echo data.

[0098] The signal processing circuit 101 simultaneously transmits ultrasonic waves from the ultrasonic transducers 21 and 22 and acquires echo data based on the reflected waves of the first and second frequencies from the receiving circuits 104 and 112, respectively. The signal processing circuit 101 sequentially stores the echo data input from the receiving circuit 104 (hereinafter referred to as "first echo data") and the echo data input from the receiving circuit 112 (hereinafter referred to as "second echo data") in the memory 102 over the time width of the echo image. The signal processing circuit 101 processes the first echo data to generate an echo image and displays the generated echo image on the display unit 107. The signal processing circuit 101 may also generate an echo image from the second echo data and display it on the display unit 107. Furthermore, the user may be able to switch which echo image to display based on which echo data.

[0099] Figure 16 is a flowchart showing the calculation process for the indicator value related to Change Example 2.

[0100] The signal processing circuit 101 calculates the difference between the echo intensity based on the first frequency ultrasound and the echo intensity based on the second frequency ultrasound for each coordinate position within the measurement range 200 (S151). Furthermore, the signal processing circuit 101 calculates a representative value of the difference for each section 201 as the index value for each section 201 (S152).

[0101] Here, the representative value of the difference may be, for example, the mean, median, maximum, or minimum value of the difference in section 201. The user may arbitrarily select and set which of these to use as the indicator value.

[0102] In the above example, the second echo data was stored in memory 102 along with the first echo data. However, it is also possible to store only the echo data used to generate the echo image from both the first and second echo data in memory 102. In this case, when transmitting and receiving signals of the first and second frequencies, the difference in echo intensity at each depth should be calculated and sequentially stored in memory 102. This ensures that the difference in echo intensity of the first and second frequencies at each coordinate position on the current echo image is maintained in memory 102. The signal processing circuit 101 then reads the difference contained in each section 201 from memory 102 and calculates a representative value of the difference. This allows the index value of each section 201 to be obtained as a representative value of the difference.

[0103] The process for generating the indicator image in Modification Example 2 is the same as in the above embodiment and Modification Example 1. When an indicator image is generated by coloring each section 201 as in the embodiment, the color scale for coloring should be configured to correspond to the indicator value (representative value of the difference) in Modification Example 2. Also, when an indicator image is generated by grouping the sections 201 as in Modification Example 1, the grouping criterion should be set to correspond to the indicator value (representative value of the difference) in Modification Example 2.

[0104] The index value in Modification Example 2 is effective when the difference in reflection characteristics at different frequencies differs for each fish species. For example, the difference in reflection characteristics at different frequencies differs between fish with swim bladder and fish without swim bladder. According to the processing in Modification Example 2, as described above, an index image is constructed for each section using the difference between the echo intensity based on the first frequency ultrasound and the echo intensity based on the second frequency ultrasound as the index value. Therefore, when the difference in reflection characteristics at different frequencies differs for each fish species, the user can understand the differences in fish species between sections from the index image. This allows the user to determine whether or not multiple types of fish are mixed in the school of fish within the measurement range.

[0105] Furthermore, the user may, as appropriate, switch between applying the indicator images of Embodiment 1, Modified Example 1, and Modified Example 2. This allows the user to determine whether multiple types of fish are mixed in the school of fish within the measurement range, based on both the differences in fish density and reflectivity.

[0106] Furthermore, in the configuration shown in Figure 15, the transducer 2 is equipped with two ultrasonic transducers 21 and 22, one for the first frequency and one for the second frequency. However, if a single ultrasonic transducer can transmit and receive both the first frequency and the second frequency ultrasonic waves, the transducer 2 may be equipped with only one ultrasonic transducer. In this case, for example, the second frequency ultrasonic wave can be transmitted and received immediately after the first frequency ultrasonic wave is transmitted and received, and these can be considered as a pair for calculating the difference.

[0107] <Other examples of changes> The present invention is not limited to the embodiments described above, and various other modifications are possible to the embodiments of the present invention.

[0108] For example, in the above embodiment, the measurement range 200 was set by user operation, but the signal processing circuit 101 may automatically set the measurement range 200 by detecting the range of the fish school from the echo data. Also, the shape of the measurement range 200 does not necessarily have to be rectangular; for example, it may be an ellipse or have an uneven contour. Furthermore, the method of dividing the measurement range 200 into sections 201 is not limited to the method shown in the above embodiment; for example, the number of sections or the shape of the sections 201 may be changed. In addition, the user may be able to set the number of vertical and horizontal sections of the measurement range 200. Moreover, the method of generating an index image using the sections and index values ​​may also be a generation method other than that shown above.

[0109] Furthermore, although the above embodiment shows an example in which the present invention is applied to a fish finder 100 mounted on a ship 1, the scope of application of the present invention is not limited to this. For example, the present invention may be applied to a remote monitoring system in which an onshore server receives echo data from a transducer installed in a fixed net via a base station and displays the echo image on a user's terminal on land. In this case, the processing shown in Figures 3(a) to 4(b) and 16 is executed by the above program on the server or the user's terminal, and the image in Figure 8 or Figures 12 to 14 is displayed on the user's terminal.

[0110] In addition, embodiments of the present invention can be modified in various ways as appropriate within the scope of the claims. [Explanation of Symbols]

[0111] 20 Echo images 100 Fish finder 101 Signal Processing Circuits (Computers) 104, 112 Receiving Circuit 200 measurement range Lot 201 202, 203 Index Images Lot 203a

Claims

1. A receiving circuit that generates echo data indicating the echo intensity at each depth based on the received ultrasonic signal transmitted in the depth direction, The system includes a signal processing circuit that processes the echo data to generate an image, The aforementioned signal processing circuit is Based on the echo data, an echo image is generated in which the echo intensity is distributed in a coordinate region with depth and time as two axes. The measurement range of the fish school set in the echo image is divided into multiple sections in the direction of the two axes, Based on the echo data, the number of individual fish included in the measurement range is estimated. For each of the aforementioned sections, a value relating to the density of individual fish is calculated as an indicator value for the fish species. An indicator image of a fish school based on the aforementioned indicator value is superimposed onto the measurement range. A fish finder characterized by the following.

2. In the fish finder device according to claim 1, The value relating to the density is the number of individual fish contained in the section. A fish finder characterized by the following.

3. In the fish finder device according to claim 1, The density value is the ratio of the number of individual fish in the section to the number of individual fish in the measurement range. A fish finder characterized by the following.

4. A receiving circuit that generates echo data indicating the echo intensity for each depth based on the received signals of first and second frequency ultrasonic waves transmitted in the depth direction, The system includes a signal processing circuit that processes the echo data to generate an image, The aforementioned signal processing circuit is From the echo data based on the ultrasound of either the first or second frequency, an echo image is generated in which the echo intensity is distributed in a coordinate region with depth and time as two axes. The measurement range of the fish school set in the echo image is divided into multiple sections in the direction of the two axes, The difference between the echo intensity based on the first frequency ultrasound and the echo intensity based on the second frequency ultrasound is calculated for each section as an indicator value for the fish species. An indicator image of a fish school based on the aforementioned indicator value is superimposed onto the measurement range. A fish finder characterized by the following.

5. In a fish finder according to any one of claims 1 to 4, The aforementioned index image is an image in which each of the aforementioned sections is colored according to the magnitude of the index value of each of the aforementioned sections. A fish finder characterized by the following.

6. In a fish finder according to any one of claims 1 to 4, The aforementioned index image is an image that shows the boundaries of each group when the sections are grouped according to the magnitude of the index value. A fish finder characterized by the following.

7. An image generation method that generates an image by processing echo data indicating the echo intensity at each depth, which is generated from the received signal of ultrasonic waves transmitted in the depth direction, A step of generating an echo image in which the echo intensity is distributed in a coordinate region with depth and time as two axes, based on the echo data, The steps include dividing the measurement range of the fish school set in the echo image into multiple sections in the direction of the two axes, A step of estimating the number of individual fish included in the measurement range based on the echo data, A step of calculating a value relating to the density of individual fish in each of the aforementioned sections as an indicator value for the fish species, The process includes superimposing an indicator image of a school of fish based on the aforementioned indicator value onto the measurement range. An image generation method characterized by the following:

8. A program that causes a computer to perform a function to generate an image by processing echo data, which shows the echo intensity at each depth, generated from the received signal of ultrasonic waves transmitted in the depth direction, To the aforementioned computer, A function to generate an echo image in which the echo intensity is distributed in a coordinate region with depth and time as two axes, based on the echo data, The function divides the measurement range of the fish school set in the echo image into multiple sections in the direction of the two axes, A function to estimate individual fish included in the measurement range based on the echo data, A function to calculate a value relating to the density of individual fish in each of the aforementioned sections as an indicator value for the fish species, A program that performs the function of superimposing an indicator image of a school of fish based on the aforementioned indicator value onto the measurement range.

9. An image generation method for generating an image by processing echo data indicating the echo intensity for each depth, which is generated from received signals of first and second frequency ultrasonic waves transmitted in the depth direction, A step of generating an echo image in which the echo intensity is distributed in a coordinate region with depth and time as two axes, from the echo data based on the ultrasound of either the first or second frequency, The steps include dividing the measurement range of the fish school set in the echo image into multiple sections in the direction of the two axes, A step of calculating the difference between the echo intensity based on the first frequency ultrasound and the echo intensity based on the second frequency ultrasound for each section as an indicator value for the fish species, The process includes superimposing an indicator image of a school of fish based on the aforementioned indicator value onto the measurement range. An image generation method characterized by the following:

10. A program that causes a computer to perform a function of processing echo data indicating the echo intensity for each depth, generated from the received signal of ultrasonic waves transmitted in the depth direction, and generating an image, To the aforementioned computer, A function to generate an echo image in which the echo intensity is distributed in a coordinate region with depth and time as two axes, from the echo data based on the ultrasound of either the first or second frequency, The function divides the measurement range of the fish school set in the echo image into multiple sections in the direction of the two axes, A function to calculate the difference between the echo intensity based on the first frequency ultrasound and the echo intensity based on the second frequency ultrasound as an indicator value for each section, A program that performs the function of superimposing an indicator image of a school of fish based on the aforementioned indicator value onto the measurement range.

Images