An Observation Method for Fish School Swimming Behavior Based on High-Speed Photogrammetry Technology

Abstract

The present invention discloses a method for observing the collective swimming behavior of fish based on high-speed photogrammetry technology. The method includes: providing a transparent circulating water tank, which includes a water flow that can be adjusted in speed and stably circulated in a first direction; providing a high-speed photography device, which includes a plurality of high-speed cameras arranged around the tank body of the transparent circulating water tank, and the viewing angles of the plurality of cameras converge in a second direction, etc.; placing a fish school in the transparent circulating water tank and triggering the high-speed photography device to photograph the fish school; the present invention can, during the process of observing the collective swimming behavior of fish, use the transparent circulating water tank to adjust the change in water flow speed and make the water flow reach a stable flow field state; according to the requirements of the experiment, put different numbers of test fish into the transparent circulating water tank, use the high-speed photography device to record the collective swimming behavior, and obtain the high-precision dynamic change process of the fish body based on photogrammetry technology.

Description

Technical Field

[0001] The present invention relates to the technical field of fish school observation, and particularly relates to an observation method for fish school swimming behavior based on high-speed photogrammetry technology. Background Art

[0002] The schooling of fish has been scientifically proven to bring hydrodynamic advantages to individual fish involved. With the increasing variety of experiments that can be completed in a circulating water channel, and the introduction of modern advanced testing technologies, the accuracy of experimental data has been further improved. However, since the current circulating water channel is mainly used for experimental studies such as flow-around simulation experiments, ship model resistance tests, open water tests of propellers, and maneuverability tests, there is a lack of an experimental observation platform for fish schooling behavior and flow field based on photogrammetry technology. Therefore, the applicant proposes an observation method for fish school swimming behavior based on high-speed photogrammetry technology, which utilizes the characteristics of the circulating water channel to create a continuous and stable flow field to approximate the stable flow field in the model water area. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to propose an observation method for fish school swimming behavior based on high-speed photogrammetry technology, which can realize the observation of fish school swimming behavior.

[0004] According to one aspect of the present invention, there is provided an observation method for fish school swimming behavior based on high-speed photogrammetry technology, including:

[0005] Providing a transparent circulating water channel, which includes a water flow that can be adjusted in speed and stably circulated along a first direction;

[0006] Providing a high-speed photography device, which includes a plurality of high-speed cameras arranged around the tank body of the transparent circulating water channel, and the viewing angles of the plurality of cameras converge in a second direction;

[0007] Adjusting the water flow velocity, depth based on the output power of the transparent circulating water channel, and calibrating the water flow velocity; the water flow velocity is greater than or equal to 1.8 cm / s and less than or equal to 8.05 cm / s;

[0008] Placing a fish school in the transparent circulating water channel, and triggering the high-speed photography device to photograph the fish school.

[0009] According to another aspect of the present invention, an observation device for fish school swimming behavior based on high-speed photogrammetry technology, the observation device includes:

[0010] A transparent circulating water channel, which includes a plurality of rectifying sieves and a plurality of rectifying plates;

[0011] A high-speed photography device, the high-speed includes a number of high-speed cameras arranged around the transparent circulating water tank body, and the viewing angles of the cameras converge in a second direction;

[0012] A control device, which is used to control the output power of the transparent circulating water tank and the sensitivity, shooting frame rate, and resolution of the high-speed camera;

[0013] A trigger analysis device, which is used to trigger the high-speed camera and the coordinates of the object photographed by the high-speed camera.

[0014] It can be found that in the above solution, during the experiment of observing the schooling behavior of fish, the transparent circulating water tank can be used to adjust the change of water flow velocity and make the water flow reach a steady flow field state; according to the needs of the experiment, different numbers of experimental fish are put into the transparent circulating water tank, and the high-speed photography device is used to record the schooling behavior, and based on photogrammetry technology, the high-precision dynamic change process of the fish body can be obtained, including the position of individual fish under schooling, the schooling formation, the tail-beating frequency of individual fish, how individual fish use the vortices of their companions to move forward, etc. This data can be used to analyze the energy benefits brought by schooling and can also provide a reference for the model optimization of fluid-structure interaction numerical simulation, and can be widely applied to on-site experiments in the fields of fish schooling behavior and flow field observation. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0016] Figure 1 It is a schematic flow chart of an embodiment of the method for observing fish schooling behavior based on high-speed photogrammetry technology of the present invention;

[0017] Figure 2 It is a schematic structural diagram of an embodiment of the device for observing fish schooling behavior based on high-speed photogrammetry technology of the present invention;

[0018] Figure 3 It is one of the schematic diagrams of fish school data photographed by the method and device for observing fish schooling behavior based on high-speed photogrammetry technology of the present invention;

[0019] Figure 4 It is the second schematic diagram of fish school data photographed by the method and device for observing fish schooling behavior based on high-speed photogrammetry technology of the present invention. Detailed Embodiments

[0020] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be specifically noted that the following embodiments are only used to illustrate the present invention, but do not limit the scope of the present invention. Similarly, the following embodiments are only partial embodiments of the present invention rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0021] The present invention provides a method for observing the collective swimming behavior of fish based on high-speed photogrammetry technology, which can realize the observation of the collective swimming behavior of fish.

[0022] Please refer to Figure 1 、 Figure 2 , Figure 1 which is a schematic flowchart of an embodiment of the method for observing the collective swimming behavior of fish based on high-speed photogrammetry technology of the present invention; Figure 2 which is a schematic structural diagram of an embodiment of the device for observing the collective swimming behavior of fish based on high-speed photogrammetry technology of the present invention. It should be noted that if there are substantially the same results, the method of the present invention is not limited to Figure 1 the process sequence shown. As shown in Figure 1 ,the method includes the following steps:

[0023] S101: Provide a transparent circulating water tank, which includes a water flow that can be adjusted in speed and stably circulated along a first direction;

[0024] Furthermore, the method for the stable circulating water flow is the rectifying sieve method.

[0025] As an optional scheme of the rectifying sieve method, further, the rectifying sieve method specifically includes: providing a plurality of rectifying sieves, and arranging the plurality of rectifying sieves at intervals along the first direction on the bottom of the transparent circulating water tank; and enabling the water flow to continuously pass through the rectifying sieves.

[0026] As a preferred scheme of the rectifying sieve method, further, the rectifying sieve method specifically includes: providing a plurality of trapezoidal rectifying plates with a slope of 17° - 18° and rectifying sieves; arranging the plurality of rectifying sieves at intervals along the first direction on the top of the trapezoidal rectifying plates; and enabling the water flow to continuously pass through the rectifying sieves.

[0027] For a specific preferred scheme of this rectifying sieve method, please refer to Figure 2 , the transparent circulating water tank includes: a water tank housing (1), an inlet and outlet rectifying section (2), a corner section (3), a swimming observation chamber (4), a water pump (5) with adjustable output power, a rubber connecting pipe (6), a rectifying sieve (7);

[0028] The front end of the water inlet rectification section is connected to the rubber connecting pipe at the end of the water outlet rectification section. The other ends of the connecting pipes are respectively connected to the water outlet and the water suction port of the water pump. The rubber connecting pipe and the water pump are sealed by plastic buckles; the length of the rectification sieve is designed to be the inner wall width of the swimming observation chamber of the water tank and is placed at both ends of the swimming observation chamber. The velocimeter is placed in the middle at the end of the swimming observation chamber, and the water level covers the propeller;

[0029] Further, the material of the water tank shell (1) is transparent acrylic board, with an outer wall size of 100cm * 15cm * 25cm and a thickness of 8mm; the top is an open structure and the lower part is hollowed out. This is for the convenience of high-speed camera shooting and observation as well as convenient manufacturing.

[0030] Further, the structure of the water inlet and outlet rectification section (2) is a transparent acrylic board, with a length of 38.7cm, a wall thickness of 8mm, and a slope of 17.12°. It is non-removable. Both ends of the water inlet and outlet rectification section are connected to the water inlet and outlet rubber connecting pipes. This is to equalize the oncoming flow, avoid excessive turbulence intensity in a small area, and ensure that the water flow entering the swimming observation chamber is uneven.

[0031] Further, the corner section (3) adopts a plastic vertical elbow structure to avoid uneven flow caused by too large a bending angle of the connecting pipe in a small test site area.

[0032] Further, the material of the cluster shooting swimming observation chamber (4) is transparent acrylic board, which is convenient for test observation. Its specifications are 26cm * 15cm, with a thickness of 8mm, and the water depth is 3 - 5cm; the lower part is a hollow structure, and shading treatment can be done according to the need to avoid reflection for high-speed camera shooting.

[0033] Further, the water pump (5) with adjustable output power has a flow rate range of 1300 - 5800L / h. According to the average water depth set by the test system, the flow rate range in the swimming observation chamber is 1.8cm / s - 8.05cm / s. This is set according to the swimming habits of different fish and the differences in schooling speeds, which is convenient for test observation and flow field shooting.

[0034] Further, the inner wall of the rubber connecting pipe (6) has a threaded ring-shaped iron wire support. It is fixed to the inner wall of the water tank by waterproof tape at the water inlet and outlet ends and is sealed by plastic buckles at the water pump connection end. This is to avoid uneven water flow caused by bending of the soft rubber pipe and system sealing defects, and inaccurate calibration of the water flow velocity entering the water tank.

[0035] Further, the rectification sieve (7) includes two pieces, an inlet rectification sieve and an outlet rectification sieve. The whole is a stainless steel honeycomb structure, with specifications of 15cm * 3cm * 10cm and a thickness of 3cm. The aperture of the rectification grid on the water passing surface is not more than 2mm; this is to rectify the water flow passing through the swimming observation chamber to make it stable, with convenient manufacturing process and easy access to materials.

[0036] It can be found that in the above solution, the outer shell of the water tank is connected to a water pump with adjustable output power through rubber connecting pipes fixed at the water inlet and outlet ends. When the water level in the swimming observation chamber is filled to a depth of 5 cm, the water pump is turned on. Under the drive of the water pump, the water flow in the tank forms a circulating water flow. Starting from the water inlet end, the water flow passes through the water inlet rectification section, the water inlet rectification screen, the swimming observation chamber, the water outlet rectification screen, the rubber connecting pipe in sequence along the first direction of the water flow, and finally returns to the water pump. Further, the working power of the water pump is adjusted to change the water flow velocity of the flow field, so as to realize the regulation of the flow field of the test measurement system.

[0037] S102: Provide a high-speed photography device, which includes a number of high-speed cameras arranged around the tank body of the transparent circulating water tank, and the viewing angles of the cameras converge in a second direction;

[0038] Please refer to Figure 2 , the high-speed photography device described in S102 includes two high-speed cameras (8), a flow velocity meter (9), and a laptop computer (10) used to trigger the high-speed cameras. They are respectively placed directly above and on the side of the swimming observation chamber (4) of the transparent circulating water tank, converge inside the swimming observation chamber (4) in the second direction, fix the lens position through a tripod, and connect the laptop computer. Adjust the parameters such as the sensitivity, frame rate, contrast, and resolution of the high-speed camera and take a test shot;

[0039] Further, the high-speed camera (8) adopts an ultra-high-speed camera, and the shooting rate range is 50 - 10,000 frames. The triggering method is to trigger through the supporting software of the laptop computer (10) connected by a 10 Gigabit WLAN network cable. This is to ensure that the shooting speed is greater than the swing frequency, clearly record the fish tail swing situation of the fish within one tail swing cycle and the flow field under the current swimming condition, and facilitate the acquisition of the three-dimensional motion process of the fish body during data processing.

[0040] Further, this step of S102 also includes obtaining the photographic projection planes of a number of the high-speed photography devices, and calculating the fish school coordinate points in the real-world coordinate system based on the projection planes;

[0041] Specifically, let xyz represent the imaging coordinate system, and XYZ represent the real-world coordinate system, where the x / y axes are the imaging projection planes. Define the point O(x0, y0, z0) as the projection center point, the point P(X, Y, Z) as a point on the object in the world coordinate system, the point P'(x, y) as the projection coordinate of the P point on the imaging plane, and the three points P, C, and P' are collinear. Through camera transformation, we can get:

[0042]

[0043] where R represents a 3X3 rotation transformation matrix:

[0044]

[0045] From formulas (1) and (2), the coordinate relationship between the projection plane in the projection coordinate system and the coordinates of the real object in the real world coordinate system can be obtained, that is, the collinearity equation:

[0046]

[0047] In this way, with two or more camera projection planes, the real target point P(X, Y, Z) can be accurately solved reversely. Therefore, by using cameras at two angles to record and processing with photogrammetry software, the dynamic change process of fish during swimming can be captured.

[0048] Furthermore, install high-speed cameras at appropriate shooting positions on the dorsal and ventral sides of the swimming observation chamber and connect them to the PC-side trigger program for trial shooting. It is better if the details of the vortex changes in the swimming observation chamber can be clearly recorded.

[0049] S103: Adjust the water flow velocity, depth based on the output power of the transparent circulating water tank, and calibrate the water flow velocity; the water flow velocity is greater than or equal to 1.8 cm / s and less than or equal to 8.05 cm / s;

[0050] Furthermore, please refer to Figure 2 , the flow velocity range of the adjustable-output-power water pump (5) is 1300 - 5800 L / h. According to the average water depth set by the test system, the calculated flow velocity range in the swimming observation chamber is 1.8 cm / s - 8.05 cm / s, which is set according to the swimming habits of different fish and the differences in schooling speeds, facilitating experimental observation and flow field shooting.

[0051] S104: Place the fish school in the transparent circulating water tank and trigger the high-speed photography device to photograph the fish school;

[0052] Furthermore, adjust the output power of the water pump according to the set flow velocity from low to high, calculate the flow velocity in combination with the water volume in the tank and calibrate it with a flow velocity meter. After putting the fish school and letting it stand for a period of time until the flow field in the swimming observation chamber is stable, use a high-speed camera to photograph the schooling behavior and vortex field, and record the dynamic change process of the fish body, including the relative positions of individuals in the group, tail-beating frequency, schooling formation, etc. After completing the recording of the schooling behavior at this flow velocity, change the output power of the water pump, refer to the above steps, and record the coping strategies of the fish school's swimming behavior after the flow velocity increases after the flow field tends to be stable; repeat this operation to complete the recording of the schooling behavior at all flow velocity levels.

[0053] Furthermore, the number of fish in the swimming observation chamber is 2 - 9, and the fish species is the red nose tetra with strong swimming aggregation ability.

[0054] Furthermore, the parameters of the dynamic change process of the fish body include the position of individual fish during schooling, the schooling formation, the tail-beating frequency of individual fish, how individual fish use the vortices of their companions to move forward, etc.

[0055] It can be found that in the above solution, during the water flow cycle, fish schooling can be achieved in the swimming observation chamber, and a high-speed camera can be used to synchronously trigger shooting to record the schooling behavior and the flow field conditions during schooling: set up and connect the high-speed camera to the laptop, open the high-speed camera control software, adjust the parameters such as the frame rate, resolution, and contrast required for shooting and conduct a test shot. The output power of the water pump can be adjusted according to the set flow rate from low to high, calculate the flow rate in combination with the water volume in the tank and calibrate it with a flow meter. After putting the fish group in and letting it stand for a period of time until the flow field in the swimming observation chamber is stable, use the high-speed camera to shoot the schooling behavior and the vortex field, and record the dynamic change process of the fish body, including the relative position of individuals in the group, the tail-beating frequency, the schooling formation, etc. After recording the schooling behavior at this flow rate once, change the output power of the water pump, refer to the above steps, and after the flow field tends to be stable, record the coping strategies of the fish group's swimming behavior after the flow rate increases; repeat this operation to complete the recording of the schooling behavior at all flow rate levels. After completing this round of experiments, change the number of fish in the group from less to more (2 - 9 fish), repeat the above experimental process, change the flow rate, and record how the fish group responds to maximize the individual hydrodynamic benefits at different flow rates under different group numbers: such as data on changing the relative position of individuals in the group, the swimming tail-beating frequency, and the way of using the vortices created by the swimming of companions to move forward.

[0056] The present invention also provides an observation device for fish schooling behavior based on high-speed photogrammetry technology, which can achieve the observation of fish schooling behavior.

[0057] Please refer to Figure 2 , Figure 2 which is a schematic structural diagram of an embodiment of the observation device for fish schooling behavior based on high-speed photogrammetry technology of the present invention. In this embodiment, the observation device for fish schooling behavior based on high-speed photogrammetry technology includes

[0058] a water tank housing (1), an inlet and outlet flow straightening section (2), a corner section (3), a swimming observation chamber (4), a water pump (5) with adjustable output power, a rubber connecting pipe (6), a flow straightening sieve (7);

[0059] It also includes two high-speed cameras (8), a current meter (9), and a laptop computer (10) for triggering the high-speed cameras. A rubber connecting pipe is connected between the front end of the water inlet rectifying section and the end of the water outlet rectifying section. The other ends of the connecting pipes are respectively connected to the water outlet and the water suction port of the water pump. The rubber connecting pipe and the water pump are sealed by plastic fasteners; the length of the rectifying sieve is designed to be the inner wall width of the swimming observation chamber of the water tank and is placed at both ends of the swimming observation chamber. The current meter is placed in the middle of the end of the swimming observation chamber with the water level covering the propeller; the high-speed cameras are respectively placed directly above and on the side of the swimming observation chamber of the circulating water tank, and the lens position is fixed by a tripod and connected to the laptop computer. Adjust the parameters such as the sensitivity, frame rate, contrast, and resolution of the high-speed cameras and conduct test shots; adjust the output power of the water pump according to the set flow rate from low to high, calculate the flow rate in combination with the water volume in the tank and calibrate it through the current meter. After putting the fish group in and letting it stand for a period of time until the flow field in the swimming observation chamber is stable, use the high-speed cameras to shoot the schooling behavior and the vortex field, and record the dynamic change process of the fish body, including the relative position of individuals in the group, the tail-beating frequency, the schooling formation, etc. After completing the recording of the schooling behavior at this flow rate once, change the output power of the water pump, refer to the above steps, and after the flow field tends to be stable, record the coping strategies of the fish group swimming behavior after the flow rate increases; repeat this operation to complete the recording of the schooling behavior at all flow rate levels.

[0060] Further, the material of the water tank shell (1) is transparent acrylic board, with an outer wall size of 100cm * 15cm * 25cm and a thickness of 8mm; the top is an open structure and the lower part is hollowed out. This is for the convenience of shooting and observing by the high-speed cameras and for the convenience of processing and manufacturing.

[0061] Further, the structure of the water inlet and outlet rectifying section (2) is a transparent acrylic board, with a length of 38.7cm, a wall thickness of 8mm, and a slope of 17.12°. It is non-removable. Both ends of the water inlet and outlet rectifying section are connected to the water inlet and outlet rubber connecting pipes. This is to uniformize the incoming flow, avoid excessive turbulence intensity in a small area, and make the water flow entering the swimming observation chamber uneven.

[0062] Further, the corner section (3) adopts a plastic vertical elbow structure to avoid uneven flow caused by too large a bending angle of the connecting pipe in a small test site area.

[0063] Further, the material of the cluster shooting swimming observation chamber (4) is transparent acrylic board, which is convenient for test observation. Its specifications are 26cm * 15cm, with a thickness of 8mm and a water depth of 3 - 5cm; the lower part is a hollow structure, and shading treatment can be done according to the need to avoid reflection for high-speed camera shooting.

[0064] Further, the flow rate range of the water pump (5) with adjustable output power is 1300 - 5800 L / h. According to the average water depth set by the test system, the flow rate range in the swimming observation chamber is 1.8 cm / s - 8.05 cm / s, which is set according to the swimming habits of different fish and the differences in schooling speeds, facilitating test observation and flow field photography.

[0065] Further, the inner wall of the rubber connecting pipe (6) is supported by a threaded ring-shaped iron wire, fixed to the inner wall of the water tank through waterproof tape at the water inlet and outlet ends, and sealed by a plastic buckle at the water pump connection end. This is to avoid uneven water flow caused by the bending of the soft rubber pipe and system sealing defects, and inaccurate calibration of the water flow rate entering the water tank.

[0066] Further, the rectifying sieve (7) includes two parts: an inlet rectifying sieve and an outlet rectifying sieve, with an overall stainless steel honeycomb structure, a specification of 15 cm * 3 cm * 10 cm, a thickness of 3 cm, and the aperture of the rectifying grid on the water passing surface not greater than 2 mm. This is to rectify the water flow passing through the swimming observation chamber to make it stable, with a convenient manufacturing process and easily available materials.

[0067] Further, the high-speed camera (8) uses a Phantom MIRO M110 high-speed camera, with a shooting rate range of 50 - 10000 frames, and the triggering method is triggered by the supporting software connected to the laptop computer (10) through a 10 Gigabit WLAN network cable. This is to ensure that the shooting speed is greater than the swinging frequency, clearly record the fish tail swinging situation of the fish within one tail-swinging cycle and the flow field under the current swimming condition, and facilitate the acquisition of the three-dimensional movement process of the fish body during data processing.

[0068] Further, the flow velocity meter (9) is a handheld portable open-channel flow velocity meter, which is used to calibrate the flow velocity under variable test fields and is convenient to use.

[0069] Further, the number of fish in the swimming observation chamber is 2 - 9, and the fish species is the red nose scissors fish with strong swimming aggregation.

[0070] Further, the parameters of the dynamic change process of the fish body include the position of individual fish under schooling, the schooling formation, the tail-swinging frequency of individual fish, and how individual fish use the vortices of their companions to move forward, etc.

[0071] The working mode of this device is as follows:

[0072] 1. Turn on the water pump (5), water flows out from the rubber connecting pipe (6), and successively flows through the inlet rectifying section (2), the inlet rectifying sieve (7), the swimming observation chamber (4), the flow velocity meter (9), the outlet rectifying sieve (7), the outlet rectifying section (2), the corner section (3), the rubber connecting pipe (6), and finally flows back to the water pump to achieve circulation.

[0073] 2. During the water flow cycle, the swimming observation chamber enables fish to swim in schools, and a high-speed camera is used to synchronously trigger shooting to record the schooling behavior and the flow field conditions under schooling: Set up and connect the high-speed camera to the laptop, open the high-speed camera control software, adjust parameters such as the frame rate, resolution, and contrast required for shooting and conduct a test shot. Adjust the pump output power according to the set flow rate from low to high, calculate the flow rate in combination with the water volume in the tank and calibrate it with a current meter. After putting the fish group in and letting it stand for a period of time until the flow field in the swimming observation chamber is stable, use the high-speed camera to shoot the schooling behavior and the vortex field, and record the dynamic change process of the fish body, including the relative position of individuals in the group, the tail-beating frequency, the schooling formation, etc. After completing the recording of the schooling behavior at this flow rate once, change the pump output power, refer to the above steps, and after the flow field tends to be stable, record the coping strategies of the fish group's swimming behavior after the flow rate increases; repeat this operation to complete the recording of the schooling behavior at all flow rate levels. After completing this round of experiments, change the number of fish in the group, from less to more (2 - 9 fish), repeat the above experimental process, change the flow rate, and record the coping methods of the fish group at different flow rates for maximizing the individual hydrodynamic benefits under different group numbers: such as data on changing the relative position of individuals in the group, the swimming tail-beating frequency, the way of advancing by using the vortices created by the swimming of companions, etc. The shooting data is as Figure 3 、 Figure 4 shown.

[0074] The working principle of this device is as follows:

[0075] Working Principle 1: The fish schooling behavior observation device of the present invention is based on high-speed photogrammetry technology. The water flow at the water inlet connecting pipe is stabilized by two system parts with rectifying functions (the rectifying section and the rectifying sieve), and the water tank is formed into a closed loop through the connecting pipe, so that the water flow can circulate smoothly in the water tank; the flow rate in the swimming observation chamber is calculated based on the water volume in the water tank and the pump output power and calibrated using an open-channel current meter; the original data can be obtained by shooting the schooling behavior and vortices at this flow rate with a high-speed camera;

[0076] Working Principle 2: Photogrammetry is a method of measurement using two-dimensional images taken by a camera to determine the position, shape, size, and even the movement of an object in three-dimensional space. Let xyz represent the imaging coordinate system, and XYZ represent the real-world coordinate system, where the x / y axes are the imaging projection plane. Define the point O(x0, y0, z0) as the projection center point, the point P(X, Y, Z) as a point on the object in the world coordinate system, the point P'(x, y) as the projection coordinates of the point P on the imaging plane, and the three points P, C, and P' are collinear. Through camera transformation, we can get:

[0077]

[0078] where R represents a 3X3 rotation transformation matrix:

[0079]

[0080] From formulas (1) and (2), the coordinate relationship between the projection plane in the projection coordinate system and the coordinates of the real object in the real world coordinate system can be obtained, that is, the collinearity equation:

[0081]

[0082] Thus, with two or more camera projection planes, the real target point P(X, Y, Z) can be accurately solved in reverse. Therefore, by using cameras at two angles to record and processing with photogrammetry software, the dynamic change process of fish during swimming can be captured.

[0083] The above are only some embodiments of the present invention, and thus do not limit the protection scope of the present invention. Any equivalent device or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. An observation method for fish school swimming behavior based on high-speed photogrammetry technology, characterized in that Comprising: Provided is a transparent circulating water tank, which includes a water flow that circulates stably at adjustable speed in a first direction; Provided is a high-speed photography device, which includes two high-speed cameras arranged around the tank body of the transparent circulating water tank, and the two high-speed cameras are respectively placed directly above and on the side of the swimming observation chamber of the transparent circulating water tank, and the viewing angles of the two high-speed cameras converge in a second direction, i.e., inside the swimming observation chamber, and the shooting rate ranges from 50 to 10,000 frames; adjusting the water flow velocity and depth based on the output power of the transparent circulating water tank, and calibrating the water flow velocity; the water flow velocity is greater than or equal to 1.8 cm / s and less than or equal to 8.05 cm / s; Placing a fish school in the transparent circulating water tank and triggering the high-speed photography device to photograph the fish school; The step of placing a fish school in the transparent circulating water tank and triggering the high-speed photography device to photograph the fish school further includes obtaining the photographic projection planes of the two high-speed photography devices, calculating the coordinate points of the fish school in the real-world coordinate system based on the projection planes, and measuring the position, shape, size, and movement of the fish school in three-dimensional space based on the two projection planes.

2. The method for observing the swimming behavior of fish schools based on high-speed photography measurement technology according to claim 1, wherein The method for the stable circulating water flow is the rectifying sieve method.

3. The method for observing the swimming behavior of fish schools based on high-speed photography measurement technology according to claim 2, wherein The rectifying sieve method specifically includes: providing a plurality of rectifying sieves and arranging the plurality of rectifying sieves at intervals along the first direction on the bottom of the transparent circulating water tank; and enabling the water flow to continuously pass through the rectifying sieves.

4. The method for observing the swimming behavior of fish schools based on high-speed photography measurement technology according to claim 2, wherein The rectifying sieve method specifically includes: providing a plurality of trapezoidal rectifying plates with a slope of 17° - 18° and rectifying sieves; arranging the plurality of rectifying sieves at intervals along the first direction on the top of the trapezoidal rectifying plates; and enabling the water flow to continuously pass through the rectifying sieves.

5. The method for observing the swimming behavior of fish schools based on high-speed photography measurement technology according to claim 3 or 4, wherein The aperture of the rectifying sieve is not greater than 2 mm.

6. The method for observing the swimming behavior of fish schools based on high-speed photography measurement technology according to claim 1, wherein The step of providing a high-speed photography device, which includes a plurality of high-speed cameras arranged around the tank body of the transparent circulating water tank, and the viewing angles of the plurality of cameras converge in a second direction, further includes setting the sensitivity, shooting frame rate, and resolution of the high-speed cameras.

7. An observation device for fish school swimming behavior based on high-speed photogrammetry technology, characterized in that, The observation device includes: A transparent circulating water tank, which includes a plurality of rectifying sieves and a plurality of rectifying plates; A high-speed photography device, the high-speed device includes several high-speed cameras arranged around the tank body of the transparent circulating water tank, and two high-speed cameras are respectively placed directly above and on the side of the swimming observation chamber of the transparent circulating water tank, and the viewing angles of the two high-speed cameras converge in a second direction, that is, inside the swimming observation chamber; placing the fish school in the transparent circulating water tank, and the steps of starting the high-speed photography device to photograph the fish school further include obtaining the photographic projection planes of the two high-speed photography devices, calculating the coordinate points of the fish school in the real-world coordinate system based on the projection planes; determining the position, shape, size, and movement of the fish school in three-dimensional space based on the two projection planes. A control device, which is used to control the output power of the transparent circulating water tank and the sensitivity, shooting frame rate, and resolution of the high-speed camera. A trigger analysis device, which is used to trigger the high-speed camera and the coordinates of the object photographed by the high-speed camera.

8. The fish school collective swimming behavior observation device based on high-speed photography measurement technology according to claim 7, characterized in that The transparent circulating water tank includes a plurality of trapezoidal rectifying plates with a slope of 17°-18° and rectifying sieves with an aperture not larger than 2 mm; and the plurality of rectifying sieves are arranged at intervals along the first direction on the top of the trapezoidal rectifying plates.

Images