Apparatus and method for calculating the shape of aquatic animals

Abstract

To accurately calculate a shape, weight of an aquatic animal in water such as fish.SOLUTION: An aquatic animal shape calculation device calculates a shape and weight of a fish, and includes: a transducer for transmitting a first and a second ultrasonic waves to a fish to generate a first echo signal from a first reflected wave and a second echo signal from a second reflected wave, respectively; an incident angle calculation unit for calculating a first incident angle of the first ultrasonic wave and a second incident angle of the second ultrasonic wave for the fish based on the first echo signal and the second echo signal; a distance between portions calculation unit for calculating a first internal distance between a first portion of the fish and a second portion different from the first portion based on the first echo signal and calculating a second internal distance based on the second echo signal in the same way; and an internal structure information unit for storing the first incident angle and the first internal distance as a first incident angle-internal distance pair and the second incident angle and the second internal distance as a second incident angle-internal distance pair to store an internal structure of the fish based on both first and second incident angle-internal distance pairs.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to calculating the shape of aquatic animals using an ultrasonic device, and particularly to signal processing for shape calculation in an aquaculture environment or the like.

Background Art

[0002] In an aquaculture environment such as a fish farm, aquatic animals such as fish are bred in a cage (for example, a fish net surrounding them if they are fish), and in order to confirm that the fish are being properly bred, it is necessary to periodically measure the size or weight of the fish. If the fish species is identified and its size can be measured, the approximate weight can also be estimated. And the size and weight of the fish can be measured by measuring the internal structure and shape of the fish. Also, in order not to stress or damage the fish, it is preferable to remotely measure (here, it means non-contact measurement) the internal structure and shape of the fish without actually catching or touching it.

[0003] As a method for remotely measuring the structure or shape of a fish, an underwater camera is installed in a cage (fish net), and an image of the fish is acquired. Next, the shape and size of the fish can be calculated from the image. Alternatively, there is also a conventional method of using X-rays as another method for measuring the shape of aquatic animals such as fish. The advantage of X-rays compared to a camera is that both the inside and outside of the fish's structure or shape can be measured, while a camera generally can only measure the external shape of the fish. The ability to measure the internal structure or shape of a fish is likely to lead to an improvement in measuring the size or weight of the fish. However, while the fish is swimming in the cage (fish net), it is difficult to measure the internal structure or shape of the fish with X-rays due to the continuous movement of the fish.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] The present invention aims to improve the accuracy of measuring the size and weight of aquatic animals (e.g., fish) when measuring their internal structure and shape while they are moving in water. [Means for solving the problem]

[0006] The present invention provides an aquatic animal shape calculation device comprising a transducer, an incident angle calculation unit, an inter-part distance calculation unit, and an internal structure information unit.

[0007] The transducer transmits a first ultrasonic wave and a second ultrasonic wave to an aquatic animal in the water, such as a fish, and generates a first echo signal from the first reflected wave and a second echo signal from the second reflected wave, respectively, reflected by the fish's body. The incident angle calculation unit calculates the first incident angle of the first ultrasonic wave to the fish's body based on the first echo signal and the second incident angle of the second ultrasonic wave to the fish's body based on the second echo signal. The inter-part distance calculation unit calculates a first internal distance between a first part of the fish's body and a second part different from that part based on the first echo signal and calculates a second internal distance between the first part and the second part of the fish's body based on the second echo signal. The internal structure information unit stores the first angle of incidence and the first internal distance as the first angle of incidence-internal distance pair, and the second angle of incidence and the second internal distance as the second angle of incidence-internal distance pair, and stores the internal structure of the fish based on the first angle of incidence-internal distance pair and the second angle of incidence-internal distance pair.

[0008] In the aquatic animal shape calculation device described above, the second ultrasonic wave is transmitted after the first ultrasonic wave, and the incident angle calculation unit may calculate the second incident angle based on the first distance between the fish and the transducer in the first echo signal and the second distance between the fish and the transducer in the second echo signal. Here, the incident angle calculation unit may calculate the second incident angle by assuming that the first distance and the second distance each change along a hyperbola with time.

[0009] Furthermore, the incident angle calculation unit may calculate the first incident angle by determining the first position of the fish located within the transducer beam based on the first echo signal, and calculate the second incident angle by determining the second position of the fish located within the transducer beam based on the second echo signal.

[0010] In the aquatic animal shape calculation device described above, the incident angle calculation unit may calculate the first position and the second position, respectively, using interferometry. Furthermore, the device may be configured to include a weight calculation unit that calculates the weight of the fish by multiplying the first internal distance raised to a predetermined first value by the second internal distance raised to a predetermined second value.

[0011] Alternatively, the transducer may transmit a first ultrasonic wave and a second ultrasonic wave to multiple fish, the incident angle calculation unit may calculate the first and second incident angles for these multiple fish, the inter-part distance calculation unit may calculate the first and second internal distances for these multiple fish, and the internal structure information unit may store the internal structures of these multiple fish.

[0012] The aquatic animal shape calculation device further includes a distribution calculation unit that calculates the distribution of incident angles and internal distances of multiple fish from the internal structures of the multiple fish, and an internal structure information unit that further stores the above distribution as the overall internal structure of the multiple fish. Here, the distribution showing the overall internal structure may be a histogram showing the number of individuals of the multiple fish in each of the divided incident angle and internal distance ranges.

[0013] Furthermore, the aquatic animal shape calculation device may be configured to include an average weight calculation unit that extracts multiple internal distances from the above distribution at multiple incident angles corresponding to multiple internal distances, and calculates the average weight based on the extracted multiple internal distances to calculate the average weight of multiple fish. This average weight calculation unit can be configured to calculate the average weight based on the multiplication of values ​​obtained by raising each of the multiple internal distances to a predetermined value.

[0014] The aquatic animal shape calculation device may further be configured to include a motor coupled to the transducer, which causes the transducer to transmit a first ultrasonic wave in a first direction and a second ultrasonic wave in a second direction different from the first direction. The transducer may also be configured to include a first transducer element that transmits a first ultrasonic wave and a second transducer element that transmits a second ultrasonic wave, arranged at a predetermined distance from each other. The first transducer element and the second transducer element may each transmit the first ultrasonic wave and the second ultrasonic wave in different directions.

[0015] The present invention provides a method for calculating the shape of an aquatic animal, which involves transmitting a first ultrasonic wave and a second ultrasonic wave to an aquatic animal in water, such as a fish, and generating a first echo signal from the first reflected wave and a second echo signal from the second reflected wave, respectively, reflected by the fish's body. Based on the first echo signal, the first incident angle of the first ultrasonic wave to the fish is calculated, and based on the second echo signal, the second incident angle of the second ultrasonic wave to the fish is calculated. Based on the first echo signal, the first internal distance between a first part of the fish and a second part different from that part is calculated, and based on the second echo signal, the second internal distance between the first part and the second part of the fish is calculated. The first incident angle and the first internal distance are then stored as the first incident angle-internal distance pair, and the second incident angle and the second internal distance are stored as the second incident angle-internal distance pair. Based on the first incident angle-internal distance pair and the second incident angle-internal distance pair, the internal structure of the fish is stored.

[0016] Here, the second ultrasound may be transmitted after the first ultrasound, and the second incident angle may be calculated based on the first distance between the fish and the transducer in the first echo signal and the second distance between the fish and the transducer in the second echo signal, assuming that the first and second distances change over time along a hyperbola.

[0017] Furthermore, the first position of the fish within the transducer beam may be calculated based on the first echo signal to calculate the first angle of incidence, and the second position of the fish within the transducer beam may be calculated based on the second echo signal to calculate the second angle of incidence. Here, the first and second positions can be calculated, for example, using interferometry.

[0018] In the above method for calculating the shape of aquatic animals, the weight of the fish may be calculated by multiplying the value obtained by raising the first internal distance to a predetermined first value by the value obtained by raising the second internal distance to a predetermined second value.

[0019] The present invention provides a computer program that, when executed by a computer, includes a computer executable instruction that causes the computer to perform the following actions: first ultrasonic waves transmitted to an aquatic animal in water generate a first echo signal from a first reflected wave reflected by the aquatic animal, such as a fish; second ultrasonic waves transmitted to an aquatic animal in water generate a second echo signal from a second reflected wave reflected by the fish's body; first, based on the first echo signal, determine the first incident angle of the first ultrasonic waves toward the fish; and second, based on the second echo signal, determine the first incident angle of the first ultrasonic waves toward the fish. A computer program is provided that calculates the second incident angle of a second ultrasonic wave directed at a fish, calculates the first internal distance between a first part of the fish and a second part different from that part based on the first echo signal, calculates the second internal distance between the first part and the second part of the fish based on the second echo signal, stores the first incident angle and the first internal distance as the first incident angle-internal distance pair and the second incident angle and the second internal distance as the second incident angle-internal distance pair in memory, and stores the internal structure of the fish based on the first incident angle-internal distance pair and the second incident angle-internal distance pair. [Effects of the Invention]

[0020] This technology can measure the internal structure or shape of aquatic animals that move underwater, such as fish, and improve the accuracy of measuring their size or weight.

Brief Description of the Drawings

[0021] The content described in the section of the mode for carrying out the invention can be understood more deeply by referring to the drawings. Here, similar parts and components are denoted by the same numerals throughout. The following description is intended only as one embodiment, and shows the embodiment only as one embodiment of the apparatus, system, and method that coincide with the subject matter claimed in the specification, and is not limited thereto.

[0022] In the following embodiments, fish in a fish farm will be taken up as one embodiment of aquatic animals for explanation. However, as long as the present invention can be applied, it is not limited to the fish in the fish farm. Examples of aquatic animals include, in addition to fish, shrimps, and even mammals such as dolphins, but are not limited thereto.

[0023] [Figure 1] FIG. 1 is a block diagram showing the overall configuration of a fish shape calculation device (aquatic animal shape calculation device) according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing a fish shape calculation device (aquatic animal shape calculation device) in a cage according to an embodiment of the present invention. [Figure 3] FIG. 3 shows examples of envelopes of the first, second, and third echo signals generated based on the first, second, and third ultrasonic waves, respectively. [Figure 4A] FIG. 4A shows a fish tracked at two positions using two consecutive transmissions by a transducer according to an embodiment of the present invention. [Figure 4B] FIG. 4B is a diagram showing a fish tracked at two positions using two consecutive transmissions by a transducer according to another embodiment of the present invention. [Figure 4C] FIG. 4C shows a fish tracked at two positions using two consecutive transmissions by a transducer according to yet another embodiment of the present invention. [Figure 5]Figure 5 shows one embodiment of the envelope of an echo signal generated based on ultrasound. [Figure 6] Figure 6 shows the internal structure of a fish, obtained based on the correspondence between the angle of incidence and the internal distance of an individually tracking fish. [Figure 7] Figure 7 is a block diagram showing the overall configuration of a fish shape calculation device (aquatic animal shape calculation device) according to another embodiment of the present invention. [Figure 8] Figure 8 is a histogram showing the distance between the float and the back as a function of the ultrasonic incidence angle, according to an embodiment of the present invention. [Figure 9A] Figure 9A shows the relative positional relationship between the swim bladder and the back of fish swimming in the fish farm net, obtained from a histogram. [Figure 9B] Figure 9B shows the global internal structure obtained based on the correspondence between the angle of incidence and the global internal distance of multiple fish. [Figure 10A] Figure 10A is a top view showing the calculation of the incident angle when the transducer includes a single receiving channel, according to one embodiment of the present invention. [Figure 10B] Figure 10B is a side view showing the calculation of the incident angle when the transducer includes a single receiving channel, according to one embodiment of the present invention. [Figure 11] Figure 11 shows various echo signals generated at different time instances (transmission timings) when a fish swims under a single receiving channel transducer. [Figure 12] Figure 12 shows a transducer coupled to a motor that transmits first and second ultrasonic waves to a fish in different directions at different time instances. [Figure 13] Figure 13 shows fish tracking using a transducer having first and second transducer elements. [Figure 14] Figure 14 is a flowchart showing a method for calculating the shape of aquatic animals according to an embodiment of the present invention. [Modes for carrying out the invention]

[0024] The embodiments for carrying out the present invention will be described in detail with due reference to the drawings as appropriate. The description below is not intended to limit the subject matter of the invention as described in the claims, but is intended to describe only one embodiment, and other modifications, i.e., arrangements, substitutions, combinations, separations, and designs in various different configurations as the basis for this embodiment, may be made as appropriate.

[0025] Figure 1 is a block diagram showing the overall configuration of an aquatic animal shape calculation device (hereinafter referred to as "fish shape calculation device") 100 according to one embodiment of the present invention. In this embodiment, fish farmed in a fish farm net are used as an example of a target existing in water, but the target is not limited to this and can be any aquatic animal, such as a mammal like a dolphin. Therefore, where the term "target" is used, it can be appropriately written as "fish".

[0026] Figure 2 is a perspective view showing the fish shape calculation device 100 inside the fish farm net 200.

[0027] The fish farm net 200 is constructed as a net-like fish farm and includes a frame 202, floats 204, a net 206, and a pier 208. The frame 202 is formed in a loop shape in plan view and has multiple floats 204 attached to it so that it can float on the water surface. The frame 202 is connected to a weight on the bottom of the water by a mooring rope (not shown).

[0028] In this embodiment, the frame 202 is formed in a loop shape and is connected to the weight by a mooring rope, but is not limited thereto. In various other embodiments, the frame 202 may be formed to have any suitable shape and may be connected to the weight by any suitable technique.

[0029] The upper end of the fish farm net 206 is fixed to the frame 202, and it is suspended in a way that partitions the water, creating a closed space in which known species of fish are raised. The pier 208 is fixed to the frame 202 for carrying out various aquaculture operations.

[0030] A float 210 is suspended approximately in the center of the frame 202, and the float 210 is connected to the bridge pier 208 with a rope. The aquatic animal shape calculation device 100 of this embodiment is placed on the float 210. As shown in Figure 1, the fish shape calculation device 100 comprises a transducer 102, a transmitting and receiving unit 104, and a signal processing unit 106.

[0031] The transducer 102 has the function of mutually converting electrical signals and ultrasonic vibrations, and uses ultrasonic transmission waves to detect aquatic animals such as fish in the water. In one embodiment, the transducer 102 is attached to the bottom of the float 210. The transducer 102 is positioned to transmit ultrasonic waves downward from above the water surface in the fish farm net 200 toward aquatic animals, and during transmission, it converts a high-power transmission signal supplied by the transmitting / receiving unit 104 into ultrasonic waves and transmits them into the water.

[0032] The transducer 102 receives reflected waves caused by ultrasound being reflected by aquatic animals. During reception, the transducer 102 receives reflected waves from underwater targets such as aquatic animals, converts these reflected waves into electrical signals, i.e., echo signals, and outputs the corresponding echo signals to the transmitting / receiving unit 104. One cycle of transmitting ultrasound and receiving its reflected waves is called a "ping". Once one transmission / receiving cycle is completed, the cycle of transmitting ultrasound and receiving reflected waves is repeated again. In one embodiment, the transducer 102 transmits a first ultrasound followed by a second ultrasound towards a fish, and the reflected waves from the fish generate the first and second echo signals, respectively.

[0033] The transmitting / receiving unit 104 is connected to the transducer 102 via an electrical cable and outputs an electrical signal to the transducer 102 via the electrical cable for the transducer 102 to transmit first and second ultrasonic waves. Furthermore, the transmitting / receiving unit 104 acquires the first and second echo signals generated by the transducer 102 based on the reflected waves via the electrical cable. The transmitting / receiving unit 104 may also be configured to amplify and filter the corresponding echo signals, convert the corresponding echo signals (analog signals) into a received signal which is a digital signal, and store it in the memory (not shown) of the signal processing unit 106.

[0034] As shown in Figure 1, the signal processing unit 106 includes a tracking unit 108, an ultrasonic incidence angle calculation unit 110, an inter-part distance calculation unit 112, an internal structure information unit 114, and a weight calculation unit 116. The signal processing unit 106 can be configured as a known computer and is communicatively coupled to the transmitting / receiving unit 104 via a communication cable to acquire received signals from the transducer 102. The signal processing unit 106 receives, stores, and processes echo signals to calculate the internal structure of the fish and measure the fish's body length, body width, body height, and / or weight. Specifically, the signal processing unit 106 includes a CPU, ROM, RAM, etc. The ROM, etc., may store a program for realizing the aquatic animal (fish) shape calculation method of the present invention.

[0035] Furthermore, the calculation of the internal structure of fish is not limited to fish raised in a fish farm net 200; for example, the fish shape calculation device 100 may be attached to a fishing boat and used as a device to calculate the internal structure of a school of fish swimming in the sea.

[0036] Figure 3 shows one embodiment of the envelope 300 for the first echo signal 301, the second echo signal 302, and the third echo signal 303, which are generated based on the first ultrasonic wave T_1, the second ultrasonic wave T_2, and the third ultrasonic wave T_3, respectively. The first ultrasonic wave T_1, the second ultrasonic wave T_2, and the third ultrasonic wave T_3 are transmitted sequentially, and the corresponding first echo signal 301, the second echo signal 302, and the third echo signal 303 are stored in memory (not shown). Hereinafter, the first ultrasonic wave, the second ultrasonic wave, and the third ultrasonic wave will also be referred to as the first Ping, the second Ping, and the third Ping, respectively.

[0037] In Envelope 300, the horizontal axis represents time, and the vertical axis represents Target Strength (TS), which indicates the intensity of the received echo signal. Target Strength is a parameter that indicates the extent to which some of the ultrasound scattered by the fish returns in the direction of incidence, and can be considered to be substantially the same as, or correlated with, the intensity of the echo signal.

[0038] Referring to Figures 1 and 3, the tracking unit 108 tracks the position of aquatic animals such as fish among the underwater targets over time, using the first echo signal 301, the second echo signal 302, and the third echo signal 303, which correspond to the first ultrasonic wave T_1, the second ultrasonic wave T_2, and the third ultrasonic wave T_3, respectively.

[0039] The tracking unit 108 is configured to extract the peak of the echo signal resulting from the reflected wave reflected by the swim bladder from the first echo signal 301, the second echo signal 302, and the third echo signal 303, and to determine whether the intensity of the echo signal (Target Strength: hereinafter referred to as "TS") is above a predetermined detection threshold. Echo signal peaks that exceed the predetermined detection threshold are considered to be due to reflected waves from the fish's swim bladder (hereinafter referred to as "swim bladder peak"). Of the various parts of the fish, the swim bladder reflects the ultrasonic waves transmitted from the transducer 102 most strongly. Therefore, as shown in Figure 3, when the TS shows the largest peak, this peak can be considered to originate from the reflected wave reflected by the swim bladder.

[0040] From this, it is thought that the peaks of the echo signal below a predetermined detection threshold correspond to echoes from other parts of the fish, such as the back or belly. Here, the predetermined detection threshold is set to -40 dB, the first echo signal 301 includes swim bladder peak P1, the second echo signal 302 includes swim bladder peak P2, and the third echo signal 303 includes two swim bladder peaks P3 and P4.

[0041] The tracking unit 108 determines, for each swim bladder peak in a given echo signal, whether there is another swim bladder peak that occurred at approximately the same time corresponding to a previously transmitted wave. If such peaks exist, the two swim bladder peak echoes can be considered to actually come from the same fish. In one embodiment, peaks P1, P2, and P3 occur at approximately the same time and can therefore be considered to originate from the same fish.

[0042] As described above, the tracking unit 108 can track a fish by comparing the peak positions on the echo signals from two consecutive ultrasonic transmissions. There is no limit to the number of transmissions when transmitting ultrasonic waves consecutively, and it is possible to track a fish with two or more transmissions. The tracking unit 108 can employ an appropriate tracking algorithm for fish tracking, including, for example, prediction using a Kalman filter.

[0043] Figure 4A shows a tracking fish 400 being tracked at two positions using two consecutive transmissions T_(n-1) and T_n by transducer 102 according to one embodiment of the present invention. The ultrasonic incidence angle calculation unit 110 calculates the incidence angle θ at which the transmitted ultrasonic waves enter the tracking fish 400 for each position of the tracking fish 400.

[0044] In one embodiment of the present invention, the transducer 102 includes one transmitter and a receiver having multiple elements divided into four receiving channels. Each receiving channel is positioned at a different location from the others and has a different directivity from the others, and receives reflected waves reflected from a target in the water. The transducer 102 then converts the received reflected waves into electrical signals, i.e., echo signals. The ultrasonic incidence angle calculation unit 110 can calculate the direction of arrival (DOA) of the echo from the pursuing fish 400 by using the conventional interferometry principle (also known as the split-beam method), that is, by calculating the phase difference between the echo signals received by the corresponding receiving channels of the transducer 102. In the conventional split-beam method, the angle between the DOA of the reflected wave and the central axis of the transmitted wave is calculated based on the phase difference.

[0045] The ultrasonic incidence angle calculation unit 110 calculates the three-dimensional position of the tracking fish 400 at each ultrasonic transmission. Specifically, the ultrasonic incidence angle calculation unit 110 calculates the distance between the tracking fish 400 and the transducer 102 based on the time difference between the transmission and reception of the echo signal of the tracking fish 400 for each position. Furthermore, the ultrasonic incidence angle calculation unit 110 calculates the three-dimensional position of the tracking fish 400 relative to the transducer 102 based on the corresponding DOA of the fish echo and the distance between the tracking fish 400 and the transducer 102. The position of the tracking fish 400 relative to the transducer 102 constitutes the fish-transducer vector 401.

[0046] It can change from one transmission to another. In this embodiment, the fish-transducer vector 401 indicates the position of the tracking fish 400 relative to the transducer 102 for the current transmission T_n.

[0047] The ultrasonic incidence angle calculation unit 110 further calculates the swimming direction vector 402 of the tracking fish 400 based on the change in the position of the tracking fish 400 from the previous transmission T_(n-1) to the current transmission T_n. The ultrasonic incidence angle calculation unit 110 calculates the incidence angle θ by calculating the angle between the swimming direction vector 402 (i.e., a first line that temporally connects two different positions of the tracked tracking fish 400) and the fish-transducer vector 401 (i.e., a second line that connects one of the two different positions to the position of the transducer 102).

[0048] The ultrasonic incidence angle calculation unit 110 calculates the incidence angle θ of the pursuing fish 400 for each position of the pursuing fish 400 based on the following formula.

number

[0049] The angle of incidence θ is the complementary angle of the angle between the swimming direction vector 402 and the fish-transducer vector 401. In one embodiment, the angle of incidence θ is zero for a fish that is vertically below the transducer 102 and swimming horizontally. There are no restrictions on the definition of the angle of incidence θ as described above, and the angle of incidence θ can be defined in any suitable way without departing from the scope of the present invention.

[0050] In another embodiment of the present invention, as shown in Figure 4B, the incident angle θ may be defined as the angle between the swimming direction vector 402 and the fish-transducer vector 401. In this embodiment, based on Equation 2, the ultrasonic incident angle calculation unit 110 calculates the incident angle θ of the ultrasonic waves to the pursuing fish 400 for each position of the pursuing fish 400.

number

[0051] In yet another embodiment of the present invention, as shown in Figure 4C, the incident angle θ may be defined as the angle between the fish-transducer vector 401 and the vertical vector 404 from the transducer 102 toward the seabed. In this embodiment, based on Equation 3, the ultrasonic incident angle calculation unit 110 calculates the incident angle θ of the tracking fish 400 for each position of the tracking fish 400.

number

[0052] In this way, the ultrasonic incidence angle calculation unit 110 calculates the incidence angle θ for each transmission (Ping) based on the corresponding echo signal. For example, the ultrasonic incidence angle calculation unit 110 calculates the first incidence angle θ_1 and the second incidence angle θ_2, respectively, corresponding to the first transmission T_n and the second transmission T_(n-1) on the tracking fish 400, based on the corresponding first and second echo signals.

[0053] The ultrasonic incidence angle calculation unit 110 calculates the first position of the tracking fish 400 within the beam of the transducer 102 based on the first echo signal corresponding to the first transmission T_n, and calculates the first incidence angle θ_1 based on this. Similarly, it calculates the second position of the tracking fish 400 within the beam of the transducer 102 based on the second echo signal corresponding to the second transmission T_(n-1), and calculates the second incidence angle θ_2 based on this. As described above, the ultrasonic incidence angle calculation unit 110 calculates the first and second positions using interferometry (conventional split-beam method).

[0054] In the embodiment described above, it is assumed that the transducer 102 transmits ultrasonic waves vertically downward from above the pursuing fish 400, but the scope of the present invention is not limited thereto. In various other embodiments, the transducer 102 may be configured to transmit ultrasonic waves vertically upward from below the pursuing fish 400.

[0055] In the above-described embodiment, the transducer 102 has multiple receiving channels, and the position of the fish within the beam of the transducer 102 is calculated using the conventional split-beam method, and the incident angle θ is calculated based on that; however, the scope of the present invention is not limited to this. In another embodiment of the present invention, the transducer 102 may have a single receiving channel, and the incident angle θ may be calculated in a method corresponding to that channel. The calculation of the incident angle θ when the transducer 102 has a single receiving channel will be described later.

[0056] Figure 5 shows one embodiment of the envelope 500 of the echo signal 501 generated based on the ultrasonic transmission T_n (Ping n).

[0057] The echo signal 501 shows several peaks depending on the species and stage of development of the chasing fish 400. In one embodiment, three peaks P5, P6, and P7 are shown, where P5 corresponds to the echo reflected from the back of the chasing fish 400, P6 corresponds to the echo reflected from the swim bladder of the chasing fish 400, and P7 corresponds to the echo reflected from the abdomen of the chasing fish 400. Depending on the species and stage of development of the chasing fish 400, there may be more than three peaks. For example, a peak corresponding to the echo reflected from the spine of the chasing fish 400 and another peak corresponding to the echo reflected from the skull of the chasing fish 400 may also be present in the echo signal 501.

[0058] To detect the echo reflected from the back of the tracking fish 400, the following processing may be performed: The transducer 102 transmits ultrasonic waves from above to below the tracking fish 400, and the echo with the maximum TS is considered to be the echo reflected from the swim bladder of the tracking fish 400. The peak of the echo signal that appears before the swim bladder peak is considered to be the echo from the back of the tracking fish 400, thereby detecting the echo reflected from the back of the tracking fish 400.

[0059] In order for the processing circuit (not shown) of the fish part distance calculation unit 112 to verify with high accuracy that the peak before the swim bladder peak actually corresponds to the back of the tracking fish 400, the following conditions should be checked. That is, this verification process checks whether there is another peak with at least a predetermined echo intensity within a predetermined time interval in a predetermined period that extends before the echo signal peak corresponding to the back of the fish and starts from the peak corresponding to the back of the fish. If no other peak exists within that time interval, the peak that appears immediately before the swim bladder peak may be detected as corresponding to the back of the fish with high accuracy. Furthermore, as another process, it is checked whether there is a section below a threshold before the peak of the back of the fish, and whether there is a time interval starting from the peak of the back of the fish where the echo intensity exceeds the threshold. If there is no echo signal intensity exceeding the threshold within the predetermined time interval, the peak that appears immediately may be detected as corresponding to the back of the fish with high accuracy.

[0060] Referring to Figures 1 and 5, the inter-part distance calculation unit 112 calculates the time difference between two peaks of an echo signal, such as the echo signal 501, generated based on the transmitted ultrasonic wave T_n (Ping n). The time difference of the echo signal 501 is multiplied by the speed of the ultrasonic waves in the water (usually 1500 m / sec) to calculate the internal distance between two corresponding parts of the fish body (hereinafter referred to as "internal distance"). In one embodiment, the inter-part distance calculation unit 112 multiplies the time difference between peak P5 and peak P6 by the speed to determine the internal distance between the back and swim bladder of the pursuing fish 400, and multiplies the time difference between peak P6 and peak P7 by the speed to determine the internal distance between the abdomen and swim bladder of the pursuing fish 400. The internal distance can be calculated in the same manner even if the parts of the fish body are other parts. In the following description, for simplicity, the explanation of distance conversion from time difference will be omitted as appropriate.

[0061] In this embodiment, the inter-part distance calculation unit 112 calculates the internal distance between the first and second parts of the fish for each echo signal. As will be understood by those skilled in the art from the above description, the inter-part distance calculation unit 112 can calculate the internal distance between any two parts of the body of the chasing fish 400, such as the back and belly, the back and swim bladder, or the belly and swim bladder. For the purposes of this discussion, the first body part will be the swim bladder, the second body part will be the back, and the internal distance will be the distance between the fish's back and swim bladder, and will be referred to as the swim bladder-back distance hereafter.

[0062] In this way, the inter-part distance calculation unit 112 calculates a first internal distance d_1 between the first body part and the second body part of the fish for the first ultrasonic transmission T_n, and calculates a second internal distance d_2 between the first body part and the second body part of the fish for the second ultrasonic transmission T_(n-1).

[0063] Each internal distance calculated for each of the multiple incident angles represents the internal structure of the aquatic animal, i.e., the chasing fish 400. The internal structure information unit 114 stores the correspondence between the calculated internal distance and the corresponding incident angle for each position of the chasing fish 400. For example, the internal structure information unit 114 stores the first incident angle θ_1 and the first internal distance d_1 as the first incident angle-internal distance pair, and the second incident angle θ_2 and the second internal distance d_2 as the second incident angle-internal distance pair, in a table as follows. [Table 1]

[0064] Table 1 illustrates three incidence angles and three internal distances calculated with three different pings, but the scope of the present invention is not limited thereto. In other embodiments, as shown below, n incidence angles and n internal distances can be calculated with n different pings. [Table 2]

[0065] Figure 6 shows the tracked fish 400 and the internal distances d_1, d_2, and d_3 over three pings (three transmissions) calculated at different incidence angles θ_1, θ_2, and θ_3. The internal structure information unit 114 stores the internal structure of the aquatic animal, i.e., the fish 400, in the format of Table 1 or Table 2.

[0066] The weight calculation unit 116 calculates the weight of the tracking fish 400 based on the internal structure of the aquatic animal. In this embodiment, once the first and second internal distances d_1 and d_2 are calculated for the tracking fish 400 being tracked, the weight calculation unit 116 calculates the weight of the tracking fish 400 by raising the first internal distance d_1 to a predetermined first value β1, raising the second internal distance d_2 to a predetermined second value β2, and then multiplying the results of each of these raising by a third predetermined value β0.

[0067] The weight of the 400 chasing fish can be expressed as shown in equation 4 below.

number

[0068] For example, for 400 individual fish that have been tracked 'N' times, the incident angles θ_1,...,θ_n and internal distances d_1,...,d_n corresponding to 'N' times are calculated, and the weight Wi of the individual fish is calculated as follows.

number

[0069] In this embodiment, the internal structure and weight of individual fish, such as the chasing fish 400, are determined, but the scope of the present invention is not limited thereto. In various other embodiments, the internal structure and weight of multiple fish can be determined without departing from the scope of the present invention.

[0070] Figure 7 is a block diagram showing the overall configuration of an aquatic animal shape calculation device (hereinafter referred to as the "fish shape calculation device" in this description) 700 according to another embodiment of the present invention.

[0071] The fish shape calculation device 700 in Figure 7 differs from the aquatic animal shape calculation device (fish shape calculation device) 100 in Figure 1 in the configuration of the histogram calculation unit 702 (distribution calculation unit) and the average weight calculation unit 704, and also does not have the weight calculation unit 116 of Figure 1. The fish shape calculation device 700 may be placed on the float 210 of the fish farm net 200 in the same manner as the fish shape calculation device 100 in Figure 1.

[0072] In this embodiment, the fish shape calculation device 700 does not include the weight calculation unit 116 shown in Figure 1. However, the scope of the present invention is not limited thereto, and in one of various other embodiments without departing from the scope of the present invention, the fish shape calculation device 700 may include the weight calculation unit 116 shown in Figure 1.

[0073] Referring to Figure 7, the transducer 102 transmits multiple ultrasonic waves to multiple fish similar to the tracking fish 400, receives multiple reflected waves reflected by the multiple fish of the multiple ultrasonic waves, and generates multiple corresponding echo signals accordingly. The transmitting / receiving unit 104 outputs multiple electrical signals to the transducer 102 via the electrical cable on which the transducer 102 transmits the multiple ultrasonic waves. The transmitting / receiving unit 104 also acquires the multiple echo signals generated by the transducer 102 based on the multiple reflected waves via the electrical cable.

[0074] Furthermore, the transmitting / receiving unit 104 may be configured to amplify and filter the corresponding multiple analog echo signals and convert them into multiple digital received signals. The tracking unit 108 tracks multiple aquatic animals, such as tracking fish 400, among the underwater targets, over time using multiple echo signals obtained from the corresponding multiple ultrasonic waves.

[0075] The ultrasonic incidence angle calculation unit 110 calculates multiple incidence angles for each of the multiple fish in the same manner as the incidence angle calculation for the tracking fish 400 described in Figure 1, that is, by calculating multiple incidence angles over multiple Ping transmissions. The ultrasonic incidence angle calculation unit 110 can calculate multiple incidence angles using any one of the aforementioned definitions of incidence angles described with reference to Figures 4A, 4B, and 4C. The inter-part distance calculation unit 112 calculates the distance between parts for each of the multiple fish based on multiple incident angles of ultrasound.

[0076] The unit calculates multiple internal distances. As a result, the inter-part distance calculation unit 112 calculates multiple internal distances for each fish between multiple transmissions / pings.

[0077] As mentioned above, the inter-part distance calculation unit 112 can calculate the internal distance between any two parts of a fish, such as the dorsal and abdominal parts, the dorsal and swim bladder, or the abdominal and swim bladder, for each angle of incidence using a method similar to that described in Figure 1. For the sake of this discussion, we will assume that the internal distance is the distance between the dorsal and swim bladder parts of the fish, and will refer to it as the swim bladder-dorsal distance from now on.

[0078] In this embodiment, the transducer 102 transmits a first ultrasonic wave T_n and a second ultrasonic wave T_(n-1) (i.e., a first transmission T_n and a second transmission T_(n-1)) to multiple fish, and generates corresponding first and second echo signals based on the reflections of the first and second ultrasonic waves from the multiple fish. Furthermore, for each fish, the ultrasonic incidence angle calculation unit 110 calculates first and second incidence angles θ_1 and θ_2, and the inter-partition distance calculation unit 112 calculates first internal distance d_1 and second internal distance d_2 corresponding to the first transmission T_n and second transmission T_(n-1), respectively.

[0079] The internal structure information unit 114 stores, for each fish, each of the multiple incident angles and the internal distance corresponding to the incident angle from among the multiple internal distances, as an incident angle-internal distance pair. In this way, the internal structure information unit 114 stores multiple such incident angle-internal distance pairs corresponding to multiple transmissions / pings for each fish. Table 3 below shows the calculation of incident angle-internal distance pairs for the two tracked fish. [Table 3] [Table 4]

[0080] In Table 3, θ_11, θ_12, and θ_13 are the first, second, and third incident angles when the first pursuing fish crosses (is exposed to) the first, second, and third ultrasonic transmissions / pings, respectively, and d_11, d_12, and d_13 are the first, second, and third internal distances of the first pursuing fish, respectively. Similarly, in Table 4, θ_21 and θ_22 are the first and second incident angles when the second pursuing fish crosses the first and second ultrasonic transmissions (pings), respectively, and d_21 and d_22 are the first and second internal distances of the second pursuing fish, respectively.

[0081] The internal structure information unit 114 stores the internal structure for each tracking fish 400, based on a number of corresponding incident angle-internal distance pairs, in a manner similar to the storage of the internal structure of the fish.

[0082] The tracking unit 108, the ultrasonic incidence angle calculation unit 110, and the inter-part distance calculation unit 112 repeatedly perform their respective calculations for a large number of transmission / reception cycles (Pings) to determine the internal distance (e.g., swim bladder-to-back distance) and incidence angle of a large number of target fish. In one embodiment, the internal distances calculated in response to the incidence angle for a large number of Pings are stored in the internal structure information unit 114 as internal distance data and incidence angle data for multiple fish.

[0083] The histogram calculation unit 702 divides the values ​​of the entire range of internal distance data and the values ​​of the entire range of incident angle data into a series of intervals, and counts the number of values ​​(frequency of occurrence) corresponding to each interval as shown in the table below. [Table 5]

[0084] In Table 5, θ_1-θ_2, θ_2-θ_3, ..., θ_(j-1)-θ_j represent a series of (continuous) divisional ranges for incident angle data, and d_1-d_2, d_2-d_3, ..., d_(i-1)-d_i represent a series of (continuous) divisional ranges for internal distance data of multiple tracking fish. In one embodiment, each divisional range of incident angle data corresponds to 1° such that each range (interval) is from -1° to 0°, 0° to 1°, etc., and each interval of internal distance data corresponds to 0.001m (meters) such that the internal distance data is from 0m to -0.001m, -0.001m to -0.002m, etc.

[0085] The count values ​​for each interval of the internal distance data and the corresponding incident angle data are stored in Table 5. Therefore, Table 5 corresponds to the overall internal structure of multiple fish. According to one embodiment, the internal structure information unit 114 stores the overall internal structure of multiple fish in the format of Table 5, for example.

[0086] Referring to Figures 7 and 8, the histogram calculation unit 702 generates a histogram 800 showing the distribution of incident angles and internal distances of multiple fish from the internal structures of multiple fish, i.e., based on Table 5. In another embodiment, the internal structure information unit 114 stores the overall internal structure of multiple fish, for example, in the form of a histogram 800. The histogram 800 is a graph of the overall internal structure of multiple fish represented in Table 5.

[0087] Histogram 800 shows the number of values ​​(counts) that fall within each range of the incident angle data and internal distance data shown in Table 5. In one embodiment, histogram 800 was obtained by tracking, collecting data from, and analyzing 29,672 yellowtail farmed in a fish farm net 200.

[0088] The dense regions in histogram 800 indicate the most frequently occurring (incident angle-internal distance) combinations. As mentioned above, transducer 102 is positioned to transmit the wave downwards from near the water surface. Therefore, negative values ​​on the horizontal axis of histogram 800 represent the dorsal side of the fish as viewed from the swim bladder position (reference position), and positive values ​​represent the ventral side of the fish as viewed from the swim bladder position.

[0089] Figure 9A shows the relative positions of the swim bladder and back of fish swimming within the fish pen net 200, obtained from the histogram 800. For example, a curve (CF, hereinafter referred to as the "fitted curve") is fitted to the trend of the histogram 800 (i.e., the dense regions of the histogram 800), and the average weight calculation unit 704 extracts internal distances D1, D2, and D3 from the histogram 800 to the reference position (swim bladder) from the fitted curve (CF), corresponding to the incidence angles A1, A2, and A3, respectively. The internal distances D1, D2, and D3 represent the overall internal distance of the fish within the fish pen net 200 at incidence angles A1, A2, and A3 to the ultrasonic tracking fish 400, respectively. The fitted curve (CF) can be fitted automatically or manually using an existing curve fitting algorithm. Figure 9B shows the overall internal structure of several aquatic animals, such as fish 900, and different angles of incidence A

[0090] The overall internal distances D1, D2, and D3 obtained in 1, A2, and A3 are shown. The internal structure information unit 114 determines the correspondence when viewing the overall picture of internal distances calculated for different angles of incidence, and stores the correspondence between internal distances and different angles of incidence as the overall internal structure of multiple aquatic animals (fish) in the form of, for example, Table 5 or Histogram 800.

[0091] In this embodiment, the dorsal-buoyancy distance at a given angle of incidence is measured using a fitted curve (CF), but the scope of the invention is not limited thereto. In various other embodiments, the dorsal-buoyancy distance can also be measured at a given angle of incidence by using the distance between the region on the histogram 800 corresponding to the maximum count and the reference position (buoyancy), without departing from the scope of the invention.

[0092] Returning to Figure 7, the average weight calculation unit 704 calculates the average weight of the tracked fish by raising each of the multiple internal distances (corresponding to the histogram 800) to a predetermined value and multiplying them. The specific formula for calculating the average weight is expressed as follows.

number

[0093] Although not shown in the diagram, the signal processing unit 106 generates display data for displaying data on the internal structure and weight of the fish. The data generated here may be further output as display data to an appropriate display device (not shown) connected to the signal processing unit 106.

[0094] In one embodiment, the weight of individual fish 400 in the holding net 200 and the average weight of all fish are measured based on the internal structure of each individual fish 400 and the overall internal structure of all fish, but the scope of the present invention is not limited thereto. In other embodiments, without departing from the scope of the present invention, the size of the fish can be measured, not limited to the weight of the fish 400. That is, the size of individual fish 400 and the average size of all fish in the holding net 200 can also be measured based on the internal structure of each individual fish 400 and the overall internal structure of all fish. The size of the fish as used herein means the so-called size of the fish and includes at least one meaning such as fish length, fish height, and fish width.

[0095] Figure 10A is a top view showing the calculation of the incident angle θ when the transducer 102 includes a single receiving channel, according to one embodiment of the present invention, and Figure 10B is a side view of the same case.

[0096] As shown in Figures 10A and 10B, the pursued fish 1000 (hereinafter referred to as "pursuing fish 1000") is assumed to be swimming in a straight line below a single-beam transducer 102 (i.e., a transducer 102 containing a single receiving channel) that is positioned vertically downward at a fixed position within the fish farm net 200. In the three-dimensional Cartesian coordinate system (3D Cartesian coordinate system) shown in Figures 10A and 10B, the transducer 102 is positioned at its center. The pursuing fish 1000 is swimming at a distance r from the transducer 102 at a velocity v.

[0097] At time t=0, the pursuing fish 1000 crosses the YZ plane. The distance r changes with time t according to the equation (hyperbola) shown in Equation 7.

number

[0098] As shown in Figure 10B, the angle of incidence θ is the angle between the fish-transducer vector 1001 (i.e., the first line connecting the pursuing fish 1000 and the transducer 102) and the perpendicular vector 1002 (i.e., the second line perpendicular to the direction in which the pursuing fish 1000 is swimming). The angle of incidence θ at time t is given by equation 8.

number

[0099] Figure 11 illustrates the various echo signals 1101, 1102, 1103, and 1104 generated at different time instances, i.e., pings n, n+1, n+2, and n+3 respectively, as the tracking fish 1000 swims under a single receiving channel transducer 102.

[0100] The distance corresponding to the distance from the tracking fish 1000 to the transducer 102 during each ping can be calculated by measuring the time it takes for the ultrasonic waves to reflect back from the swim bladder of the fish 1000, multiplying that time by the speed of sound in water, and dividing the result by 2. The distance r for each ping is given by the following: [Table 6]

[0101] Referring again to Figure 10B, it is assumed that the distance between the pursuing fish 1000 and the transducer 102 changes with time according to the hyperbolic equation 9.

number

[0102] The parameters a, b, and c in equation 9 can be determined, for example, using the least squares method. The fish's velocity v and time tp are calculated using equations 10 and 11.

number

number

[0103] Here, the ultrasonic incidence angle calculation unit 110 calculates the incidence angle θ by substituting the value of the speed v of the pursuing fish 1000 and the time tp into equation 8 for each Ping. In relation to the present invention, when the transducer 102 generates a first echo signal 1101 and a second echo signal 1102 based on first and second ultrasonic waves (i.e., first and second Ping n and n+1), the first distance r_n and the second distance r_(n+1) are calculated as described above.

[0104] In this embodiment, the second ultrasound is transmitted after the first ultrasound has been transmitted. Thus, in the second time instance, the ultrasound incidence angle calculation unit 110 calculates the second incidence angle θ_(n+1) based on the first distance r_n between the aquatic animal (i.e., the tracking fish 1000) and the transducer 102 in the first echo signal 1101 and the second distance r_(n+1) between the aquatic animal and the transducer 102 in the second echo signal 1102. The ultrasound incidence angle calculation unit 110 calculates the second incidence angle θ_(n+1) using equation 9, assuming that the first and second distances r_n,r_(n+1) change with time based on a hyperbola. As a variation, instead of just two distances, the first and second distances r_n,r_(n+1), three or more distances (first, second, and third distances r_n,r_(n+1),r_(n+2)) may be used. In this case, for example, the ultrasonic incidence angle calculation unit 110 calculates the third incidence angle θ_(n+2) using equation 9, assuming that the first, second, and third distances r_n, r_(n+1), and r_(n+2) change with time based on a hyperbola.

[0105] In the embodiments described above, the transducer 102 is fixed in one position and transmits ultrasound in a fixed direction, i.e., from above toward the fish, but the scope of the present invention is not limited thereto. In other embodiments, without departing from the present invention, the transducer 102 may be coupled to a motor 1200 to transmit a first ultrasound and a second ultrasound to a fish in different directions in two different time instances (Pings), as shown in Figure 12.

[0106] As shown in Figure 12, the motor 1200 is coupled to the transducer 102 and is configured to move (e.g., rotate) the transducer 102 to change the direction in which the transducer 102 transmits the first ultrasonic wave and the second ultrasonic wave. The transducer 102 transmits the first ultrasonic wave in a first direction in a first time instance (first ping n-1) and the second ultrasonic wave in a second direction different from the first direction in a second time instance (second ping n).

[0107] In this embodiment, a single transducer 102 is used to transmit ultrasound to a fish and receive the reflected waves, but the scope of the invention is not limited thereto. In other embodiments, without departing from the invention, two or more transducers may be used to transmit ultrasound to a fish and receive the reflected waves.

[0108] Figure 13 shows the tracking of a fish 1300 using a transducer having a first transducer element 1302 and a second transducer element 1304 (referred to here as "tracking fish 1300").

[0109] The first transducer element 1302 and the second transducer element 1304 are used to track the same fish on multiple Pings, and the ultrasonic incidence angle and internal distance are calculated at each position of the tracked fish 1300. The first transducer element 1302 and the second transducer element 1304 may be positioned at different locations and facing in different directions from each other. That is, the first transducer element 1302 and the second transducer element 1304 may be positioned at a predetermined distance from each other and facing in different directions from each other. In this way, the first transducer element 1302 and the second transducer element 1304 transmit the first and second ultrasonic waves in different directions from each other, respectively. The first transducer element 1302 and the second transducer element 1304 may transmit the first and second ultrasonic waves simultaneously at different frequencies so that the received waves can be distinguished from each other.

[0110] Based on the reflected waves of the first and second ultrasonic waves, the first transducer element 1302 and the second transducer element 1304 detect the pursuing fish 1300. If the first transducer element 1302 and the second transducer element 1304 detect the same pursuing fish 1300, the three-dimensional position of the fish detected by the first transducer element 1302 is calculated by referring to the position of the first transducer element 1302, and the three-dimensional position of the fish detected by the second transducer element 1304 is calculated by referring to the position of the second transducer element 1304.

[0111] Since the relative positions of the first transducer element 1302 and the second transducer element 1304, that is, the predetermined distance between the first transducer element 1302 and the second transducer element 1304, are known in advance, it is possible to determine whether the fish detected by both transducer elements 1302 and 1304 are in the same position, that is, whether they are actually the same fish, i.e., the tracking fish 1300.

[0112] Furthermore, for the pursuing fish 1300, a first fish-transducer vector 1306, a second fish-transducer vector 1308, and a swimming direction vector 1310 are obtained. In this way, based on the first fish-transducer vector 1306, the second fish-transducer vector 1308, and the swimming direction vector 1310, two incident angles corresponding to both the first and second ultrasonic waves, and the corresponding internal position distances can be simultaneously determined for the pursuing fish 1300.

[0113] In the above embodiment, the transducer 102 is configured to transmit an ultrasonic beam of a predetermined beam width vertically downward from above the pursuing fish 1300. However, there are no particular restrictions on the position of the transducer 102 and the orientation of the beam relative to the pursuing fish 1300. The transducer 102 can be placed in any position, and the beam can be directed in any direction as long as at least a portion of the fish is within the beam.

[0114] In the above embodiment, the weight of the individual fish is measured after calculating the internal distance at multiple pings, but the method is not limited to this. The weight of the individual fish can be calculated, for example, using equation 12 after calculating the internal distance d_1 at the angle of incidence θ_1.

number

[0115] Furthermore, the detection accuracy of tracking fish may be improved by adjusting the width of the ultrasonic beam transmitted by transducer 102 according to the water depth where the fish are located and the swimming speed of the fish. In one embodiment, the beam width is inversely proportional to the water depth where the fish are located. The change in beam width in response to a change in the water depth where the fish are located can be illustrated as shown in Table 7 below. [Table 7]

[0116] Furthermore, in one embodiment, the beam width is directly proportional to the swimming speed of the fish. The change in beam width in response to a change in the swimming speed of the fish can be shown in Table 8 below. [Table 8]

[0117] Figure 14 is a flowchart showing a method for calculating the shape of aquatic animals (fish shape calculation method) 1400 according to an embodiment of the present invention. The various steps of the aquatic animal shape calculation method 1400 have already been described with reference to Figure 1.

[0118] In step 1402, transducer 102 transmits first and second ultrasonic waves toward an aquatic animal, and in step 1404, transducer 102 generates a first echo signal and a second echo signal, respectively, from the first and second reflected waves reflected by the aquatic animal (fish).

[0119] In step 1406, the ultrasonic incidence angle calculation unit 110 calculates the first ultrasonic incidence angle and the second ultrasonic incidence angle, respectively, based on the first echo signal and the second echo signal.

[0120] In step 1408, the inter-part distance calculation unit 112 calculates a first internal distance between a first part and a second part of the aquatic animal (fish) based on the first echo signal. In step 1410, the inter-part distance calculation unit 112 calculates a second internal distance between a first part and a second part of the aquatic animal (fish) based on the second echo signal.

[0121] In step 1412, the internal structure information unit 114 stores a first angle of incidence and a first internal distance as a first angle of incidence-internal distance pair, and in step 1414, stores a second angle of incidence and a second internal distance as a second angle of incidence-internal distance pair. In step 1416, the internal structure information unit 114 stores the internal structure of the aquatic animal (fish) based on the first and second angle of incidence-internal distance pairs.

[0122] Not all objectives or benefits can necessarily be achieved by following any particular embodiment described herein. Therefore, for example, a person skilled in the art may find that a particular embodiment does not necessarily achieve other objectives or benefits taught or suggested herein, and may reconfigure it to achieve or optimize one or more of the benefits taught herein.

[0123] All processes described herein are embodied in software code that is executed by a computing system including one or more computers or processors, and may be fully automated. The software code can be stored in any type of non-temporary computer-readable medium or other computer storage device. Some or all of these methods can be embodied in dedicated computer hardware.

[0124] Many other variations not described herein are evident from this disclosure. For example, depending on the embodiment, any particular operation, event, or function of any of the algorithms described herein may be performed in different sequences and may be added, merged, or excluded as a whole (for example, not all described actions or events are required to execute the algorithm). Furthermore, embodiments, operations, or events may be executed not sequentially, but in parallel, for example, by multithreading, interrupt handling, or multiple processors or processor cores, or by other parallel architectures. Furthermore, different tasks or processes may be executed by different machines and / or computing systems that can work together.

[0125] Various exemplary logic blocks and parts described in connection with embodiments disclosed herein can be implemented or executed by a machine such as a processor. The processor may be a microprocessor, or alternatively, a controller, microcontroller, state machine, or a combination thereof. The processor may include electrical circuits configured to process computer-executable instructions. In another embodiment, the processor may include an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable device that performs logical operations without processing computer-executable instructions. The processor may also be implemented as a combination of computing devices, e.g., a combination of a digital signal processor (DSP) and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration. While this specification primarily discusses digital technologies, the processor may also primarily include analog components. For example, some or all of the signal processing algorithms described herein can be implemented by analog circuits or mixed analog-digital circuits. The computing environment may include, but is not limited to, any type of computer system based on a microprocessor, mainframe computer, digital signal processor, portable computing device, device controller, or computing engine within a device.

[0126] It should be emphasized that many variations and modifications are possible in the embodiments described above, and that these elements should be understood as just one of many other acceptable examples. All such changes and variations are intended to be included herein within the scope of the invention and are protected by the following claims. [Explanation of Symbols]

[0127] 100 Aquatic animal shape (fish) calculation device 102 Transducer 104 Transmitter / Receiver 106 Signal Processing Unit 108 Tracking part 110 Ultrasonic incidence angle calculation section 112 Inter-part distance calculation unit 114 Internal structure information department 116 Weight calculation section 200 fish tank nets 202 frames 204 Float 206 Net Pier 208 210 Floats 400 Tracking fish (aquatic animals being tracked) 401 Fish-Transducer Vector 402 Swimming direction vector 404 Vertical vector 700 Aquatic animal shape (fish) calculation device 702 Histogram Calculation Unit (Distribution Calculation Unit) 704 Average weight calculation section 900 Tracking fish 1000 tracking fish 1001 Fish-Transducer Vector 1002 Swimming direction vector 1200 motor 1300 Tracking fish 1302 First transducer element 1304 Second transducer element 1306 First fish-transducer vector 1308 Second fish-transducer vector 1310 Swimming direction vector

Claims

1. A transducer that transmits a first ultrasonic wave and a second ultrasonic wave to aquatic animals in water, and generates a first echo signal from the first reflected wave and a second echo signal from the second reflected wave, respectively, An incidence angle calculation unit calculates a first incidence angle of the first ultrasonic wave to the aquatic animal based on the first echo signal, and a second incidence angle of the second ultrasonic wave to the aquatic animal based on the second echo signal, Based on the first echo signal, a first internal distance is calculated between a first part of the aquatic animal and a second part different from that part. A part-to-part distance calculation unit calculates a second internal distance between the first part and the second part of the aquatic animal based on the second echo signal, The first angle of incidence and the first internal distance are taken as the first angle of incidence-internal distance pair. The second angle of incidence and the second internal distance are taken as the second angle of incidence-internal distance pair. An internal structure information unit that stores the first angle of incidence-internal distance pair and the second angle of incidence-internal distance pair as the internal structure of the aquatic animal, An aquatic animal internal structure calculation device equipped with [specific features / features].

2. The aquatic animal internal structure calculation device according to claim 1, The second ultrasound is transmitted after the transmission of the first ultrasound. The incident angle calculation unit calculates the second incident angle based on the first distance between the aquatic animal and the transducer in the first echo signal and the second distance between the aquatic animal and the transducer in the second echo signal. Aquatic animal internal structure calculation device.

3. The aquatic animal internal structure calculation device according to claim 2, The incident angle calculation unit calculates the second incident angle assuming that the first distance and the second distance each change along a hyperbola with time. Aquatic animal internal structure calculation device.

4. An aquatic animal internal structure calculation device according to claim 1, The incident angle calculation unit is, Based on the first echo signal, the first position of the aquatic animal located within the beam of the transducer is calculated, and the first incident angle is calculated. Based on the second echo signal, the second position of the aquatic animal located within the transducer beam is calculated, and the second incidence angle is calculated. Aquatic animal internal structure calculation device.

5. The aquatic animal internal structure calculation device according to claim 4, The incident angle calculation unit is an aquatic animal internal structure calculation device that calculates the first position and the second position, respectively, using interferometry.

6. An aquatic animal internal structure calculation device according to any one of claims 1 to 5, further comprising: Weight calculation unit calculates the weight of the aquatic animal by multiplying the value obtained by raising the first internal distance to a predetermined first value by the value obtained by raising the second internal distance to a predetermined second value. An aquatic animal internal structure calculation device equipped with [specific features / features].

7. An aquatic animal internal structure calculation device according to any one of claims 1 to 6, The transducer transmits the first ultrasonic wave and the second ultrasonic wave to a plurality of aquatic animals, including the aquatic animal, The incident angle calculation unit calculates the first incident angle and the second incident angle for the plurality of aquatic animals, The inter-part distance calculation unit calculates the first internal distance and the second internal distance for the plurality of aquatic animals, The internal structure information unit stores the internal structures of the plurality of aquatic animals. Aquatic animal internal structure calculation device.

8. The aquatic animal internal structure calculation device according to claim 7, further, The system includes a distribution calculation unit that calculates the distribution of the angle of incidence and the internal distance of the multiple aquatic animals from the internal structure of the multiple aquatic animals, The internal structure information unit further stores the distribution as the overall internal structure of the multiple aquatic animals. Aquatic animal internal structure calculation device.

9. The aquatic animal internal structure calculation device according to claim 8, The distribution showing the overall internal structure is a histogram showing the number of individuals of the multiple aquatic animals in each of the divided ranges of the incident angle and internal distance. Aquatic animal internal structure calculation device.

10. An aquatic animal internal structure calculation device according to claim 8 or claim 9, further comprising: The system includes an average weight calculation unit that extracts multiple internal distances from the distribution at corresponding angles of incidence, and calculates the average weight based on the extracted internal distances, thereby calculating the average weight of the multiple aquatic animals. Aquatic animal internal structure calculation device.

11. The aquatic animal internal structure calculation device according to claim 10, The average weight calculation unit calculates the average weight based on the multiplication of the values ​​obtained by raising each of the multiple internal distances to a predetermined power. Aquatic animal internal structure calculation device.

12. An aquatic animal internal structure calculation device according to any one of claims 1 to 11, further comprising: The system includes a motor coupled to the transducer, which causes the transducer to transmit the first ultrasonic wave in a first direction and the second ultrasonic wave in a second direction different from the first direction. Aquatic animal internal structure calculation device.

13. The aquatic animal internal structure calculation device according to claim 1, The transducer is arranged at a predetermined distance from each other and includes a first transducer element that transmits the first ultrasonic wave and a second transducer element that transmits the second ultrasonic wave. Aquatic animal internal structure calculation device.

14. The aquatic animal internal structure calculation device according to claim 13, The first transducer element and the second transducer element each transmit the first ultrasonic wave and the second ultrasonic wave in different directions from each other. Aquatic animal internal structure calculation device.

15. A first ultrasonic wave and a second ultrasonic wave are transmitted to aquatic animals in the water, and a first echo signal is generated from the first reflected wave reflected by the aquatic animals, and a second echo signal is generated from the second reflected wave. Based on the first echo signal, a first incident angle of the first ultrasound to the aquatic animal is calculated, and based on the second echo signal, a second incident angle of the second ultrasound to the aquatic animal is calculated. Based on the first echo signal, a first internal distance is calculated between a first part of the aquatic animal and a second part different from that part; and based on the second echo signal, a second internal distance is calculated between the first part and the second part of the aquatic animal. The first angle of incidence and the first internal distance are taken as the first angle of incidence-internal distance pair, and the second angle of incidence and the second internal distance are taken as the second angle of incidence-internal distance pair, The first angle-internal distance pair and the second angle-internal distance pair are stored as the internal structure of the aquatic animal. Method for calculating internal structures of aquatic animals.

16. A method for calculating the internal structure of an aquatic animal according to claim 15, The second ultrasound is transmitted after the transmission of the first ultrasound. Based on the first distance between the aquatic animal in the first echo signal and the transducer that transmits the first and second ultrasonic waves to generate the first and second echo signals, and the second distance between the aquatic animal and the transducer in the second echo signal, the second incident angle is calculated assuming that the first and second distances change along a hyperbola with time. Method for calculating internal structures of aquatic animals.

17. A method for calculating the internal structure of an aquatic animal according to claim 15, Based on the first echo signal, the first position of an aquatic animal located within the beam of a transducer that transmits the first and second ultrasonic waves to generate the first and second echo signals is calculated, and the first incident angle is calculated. Based on the second echo signal, the second position of the aquatic animal located within the transducer beam is calculated, and the second incidence angle is calculated. Method for calculating internal structures of aquatic animals.

18. A method for calculating the internal structure of an aquatic animal according to claim 17, The first and second positions are calculated using interferometry. Method for calculating internal structures of aquatic animals.

19. A method for calculating the internal structure of an aquatic animal according to any one of claims 15 to 18, further comprising: The weight of the aquatic animal is calculated by multiplying the value obtained by raising the first internal distance to a predetermined first value by the value obtained by raising the second internal distance to a predetermined second value. Method for calculating internal structures of aquatic animals.

20. A computer program that, when executed by a computer, includes computer executable instructions that cause the computer to do the following: A first ultrasonic wave transmitted to an aquatic animal in the water generates a first echo signal from the first reflected wave reflected by the aquatic animal, and a second ultrasonic wave transmitted to an aquatic animal in the water generates a second echo signal from the second reflected wave reflected by the aquatic animal. Based on the first echo signal, the first incident angle of the first ultrasound to the aquatic animal is calculated, and based on the second echo signal, the second incident angle of the second ultrasound to the aquatic animal is calculated. Based on the first echo signal, a first internal distance is calculated between a first part of the aquatic animal and a second part different from that part; and based on the second echo signal, a second internal distance is calculated between the first part and the second part of the aquatic animal. The first angle of incidence and the first internal distance are taken as the first angle of incidence-internal distance pair, and the second angle of incidence and the second internal distance are taken as the second angle of incidence-internal distance pair, The first angle-internal distance pair and the second angle-internal distance pair are stored in memory as the internal structure of the aquatic animal. Computer program.

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