Imaging system for aquatic organisms

Abstract

An imaging system for imaging aquatic organisms. The imaging system comprises an imaging device and at least two mirrors arranged to provide imaging of aquatic organisms from at least two angles. The imaging system may be equipped with two illumination sources. The imaging system can image small aquatic organisms when the small aquatic organisms pass through the flow cell.

Description

Technical Field

[0001] The present invention relates to the monitoring of small aquatic organisms. In particular, the present invention relates to an imaging system for imaging small aquatic organisms. The imaging system may be part of a flow-through imaging system. The imaging system and the flow-through imaging system can be used for repeated monitoring of, for example, the growth and health of small aquatic organisms. Background Art

[0002] Monitoring small aquatic organisms is important for a variety of reasons. There is an increasing recognition of the importance of monitoring marine ecosystems throughout the food chain. Protecting the oceans and marine ecosystems is crucial for protecting life on Earth and the diversity of nature, as well as for providing food for a growing population. Small aquatic organisms are an important part of the marine food chain, and monitoring the morphometry, growth, and density of small aquatic organisms in the ocean is significant. In, for example, the aquaculture industry, monitoring both fish larvae and their food (such as zooplankton) is important. Examples of monitoring can, for instance, involve the morphometry of small aquatic organisms, how their size changes over time, how the aquatic organisms grow and develop, the density of aquatic organisms in a cultivation pond or a fish farming sea enclosure, and the types of aquatic organisms present in the ocean or cultivation pond. It is well known that an adverse and toxic environment during the embryonic stage of fish increases the probability of developmental deformities in the hatched fish larvae, which can be used as a water quality indicator for marine monitoring.

[0003] As a further example, during the reproduction of marine fish, the spawning stage is the most demanding, and from a production perspective, this stage remains the biggest bottleneck. This is because newly hatched fish larvae are very small and the density of fish eggs in each cultivation pond is high. Marine fish larvae do not develop well after hatching. Unlike salmon, they require high-quality live prey organisms to grow and develop normally. The initial feeding stage, from when the fish larvae start feeding until they are large enough to digest formulated feed, is typically characterized by high mortality and abnormal development. The condition of fish larvae in a farming environment depends on many complex factors, such as feed quality, water quality, and fish egg quality.

[0004] Monitoring the growth of fish is very important. Good early nutrition is crucial for the later growth and development of fish. In order to achieve predictability and profitability in later production, fish larvae are monitored at an early stage. The growth, development, and appetite (stomach fullness) of fish larvae are usually monitored by removing the fish larvae from the rearing pond and measuring and scoring them under a magnifying glass or microscope. Although breeders may spend two to three months each year performing this task, the information provided is still too little to make the time invested by breeders worthwhile. A small number of fish larvae may not be sufficient to represent the entire population, and there is currently no good data recording system. This means that populations in different containers within the same facility or populations in different years cannot be compared. This also means that poorly developed populations are discovered too late to take measures.

[0005] A simple and cost-effective monitoring system is needed to monitor small aquatic organisms, which can be easily adapted to different species of aquatic organisms and environmental conditions. Summary of the Invention

[0006] The present invention provides a solution or at least alleviates some of the problems mentioned above.

[0007] The present invention provides an imaging system capable of imaging small aquatic organisms from at least two angles. The imaging system includes an imaging device and at least two mirrors. The imaging device and at least two mirrors are arranged to provide imaging of at least one aquatic organism from at least two angles.

[0008] The present invention also provides a flow-through imaging system for imaging at least one aquatic organism. At least one aquatic organism can be imaged when at least one fish larva passes through the flow-through pond. The flow-through imaging system can include a flow-through pond and the above imaging system.

[0009] The present invention also provides the uses of the imaging system and the flow-through imaging system.

[0010] The present invention provides an imaging system for imaging at least one aquatic organism. The imaging system includes an imaging device and at least two mirrors, wherein the mirrors are arranged to provide imaging of the at least one aquatic organism from at least two angles.

[0011] The imaging system may further include at least two illumination sources. The at least two illumination sources may be arranged on opposite sides of the imaging device. The imaging device may be arranged on a first side of at least one aquatic organism, while at least two mirrors are arranged on a second side of at least one aquatic organism, where the first side is opposite to the second side. The at least two mirrors may be arranged to obtain at least two reflected imaging light paths from at least one aquatic organism. The at least two mirrors and the imaging device are arranged to obtain a combined image of at least one aquatic organism from three different angles, where the images at the first and second angles are formed by at least one aquatic organism entering the imaging device after being reflected by the at least two mirrors, and the image at the third angle is formed by directly imaging at least one aquatic organism into the imaging device.

[0012] Each of the at least two mirrors may be arranged at an angle with respect to a plane perpendicular to the field-of-view axis of the imaging device, where the angle is about 15° to 45°.

[0013] Each of the at least two mirrors may be arranged at an angle of approximately 22.5° with respect to a plane perpendicular to the field-of-view axis of the imaging device to obtain two reflected imaging light paths that are approximately 90° apart from each other from the aquatic organism. Alternatively, each of the at least two mirrors may be arranged at an angle of approximately 30° with respect to a plane perpendicular to the field-of-view axis of the imaging device. The at least two mirrors are arranged to obtain a combined image of at least one aquatic organism provided by three different angular perspectives that are 120° apart from each other, where the images at two of the angles are formed by the aquatic organism entering the imaging device after being reflected by the at least two mirrors, and the image at the third angle is formed by directly imaging the aquatic organism into the imaging device. The at least two mirrors may be arranged symmetrically or approximately symmetrically with respect to the field-of-view axis of the imaging device. The at least two mirrors may be arranged such that the imaging device has the same focal region at each perspective. The imaging device may include a telecentric lens.

[0014] The images of at least two angles / sides of the at least one aquatic organism may be obtained simultaneously.

[0015] The at least one aquatic organism may be arranged to be imaged by the imaging device while flowing through a flow-through cell. The flow-through cell and the at least two mirrors may be arranged inside a container filled with a transparent material. The container may be filled with a degassed liquid or a transparent resin. The imaging device and the at least two illumination sources may be arranged inside or outside the container. The flow-through cell and the container may be transparent. The container may be made of polycarbonate or quartz. The flow-through cell may be made of polycarbonate, quartz, or plastic. The flow-through cell may further include at least one light diffuser.

[0016] The present invention also provides a flow-through imaging system for imaging at least one aquatic organism as the at least one aquatic organism passes through a flow-through cell. The system includes a flow-through cell and an imaging system. The imaging system can be the above-mentioned imaging system. The flow-through cell and at least two mirrors can be arranged within a container filled with a liquid or a transparent resin to eliminate optical distortions caused by the irregularities of the flow-through cell. The flow-through imaging system can also include a valve for regulating the flow rate through the flow-through cell.

[0017] The present invention also provides the use of the imaging system for monitoring the size or growth condition of small aquatic organisms. The imaging system or the flow-through imaging system can also be used to construct three-dimensional images of small aquatic organisms or to perform morphometric measurements on small aquatic organisms.

[0018] The flow-through imaging system can also be used to monitor the growth of fish larvae, monitor the health condition of fish larvae, perform biometric measurements on fish larvae, or monitor fish larvae in a production tank.

[0019] The small aquatic organisms can be at least one of at least fish larvae, zebrafish larvae, algae, crustaceans, zooplankton, or aquatic organism eggs.

[0020] The imaging system provides a flexible solution for imaging aquatic organisms.

[0021] The imaging system is easy to expand, suitable for imaging aquatic organisms with different sizes and shapes, and the arrangement between system components is flexible. The imaging device, the mirrors, and possibly the light source can be arranged separately independently, and can be closer or farther away from each other. The mirrors can have different areas and shapes as long as the imaging system can provide imaging of the aquatic organism from at least two angles. The imaging system can be arranged outside the possible flow-through cell, thus having flexibility in terms of the size, shape, and mutual arrangement of the imaging device, the mirrors, and possibly the light source, as described above. The imaging system with or without a flow-through cell also allows for relatively easy replacement or repair of individual components of the system. The mirrors and the flow-through cell arranged within the container also allow for convenient replacement of the container with the flow-through cell and the mirrors to adapt to different uses of the imaging system, such as monitoring other aquatic organisms, or easily replacing the mirrors and the flow-through cell in case of damage or wear. The new container can be easily connected to the light source and the imaging device, and these devices can be arranged inside or outside the container.

[0022] The imaging system is also easily adaptable to different uses, such as uses in the ocean, aquaculture, or land-sea closed systems. The imaging system can be used, for example, to determine the density of algae in the ocean, the category of algae in the ocean, the morphometry of crustaceans in open waters, to determine the growth of fish larvae, the quality of fish larvae, to measure the size of the yolk sac relative to the length, and to identify any deformities of fish larvae. Other uses may include monitoring the production of live bait, such as zooplankton, fish larvae, algae, and fish eggs, and the growth status, density, quality, etc. can be determined through morphometry.

[0023] By way of example only, the imaging system can achieve automatic imaging and analysis of fish larvae. The fish larvae can be taken out from the cultivation tank and flow through the imaging system via a flow-through tank. Machine learning can be used to analyze the images of the fish larvae. The imaging system with a flow-through tank is capable of performing automatic biometric measurements on the fish larvae. The images can be analyzed in real time. These images also allow for three-dimensional reconstruction of the fish larvae at a later stage. The flow-through imaging system provides an efficient and more accurate system for imaging a large number of fish larvae without affecting the health and survival rate of the fish larvae. Therefore, the system can be used for repeated analysis of the same group of fish larvae over time.

[0024] The above examples of fish larvae may also be applicable to other small aquatic organisms. The imaging system is used to image small aquatic organisms as exemplified in this application, but may also be applicable to small fish and other small live aquatic organisms. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Exemplary embodiments can be described with reference to the following drawings, wherein:

[0026] Figure 1 is a schematic diagram of an exemplary imaging system for imaging at least one aquatic organism from two angles;

[0027] Figure 2 is a schematic diagram of another exemplary imaging system for imaging at least one aquatic organism from three angles;

[0028] Figure 3 is a schematic diagram of an exemplary imaging system for imaging at least one aquatic organism from two angles;

[0029] Figure 4 is a schematic diagram of an exemplary imaging system related to an aquatic organism cultivation tank for monitoring aquatic organisms in the cultivation tank;

[0030] Figure 5a is a schematic diagram of an exemplary imaging system for imaging fish larvae;

[0031] Figure 5b is Figure 5aSchematic diagram of an exemplary imaging system for imaging fish larvae, showing side and front views of an imaging device, a mirror, a flow cell, and a light source;

[0032] Figure 6 Shows the use of such as Figure 5a and 5b Three images of the same zebrafish larva taken with the imaging system shown. The left and right zebrafish larva images were taken through the right and left mirrors and are rotated 90° relative to each other. The middle image is of the zebrafish larva taken directly inside the flow cell. Detailed Description

[0033] Exemplary embodiments are described with reference to the accompanying drawings. In all the drawings and throughout the specification, the same reference numerals are used to denote the same or similar features. These examples are illustrative only and do not limit the present invention.

[0034] Figure 1 An imaging system 1 for imaging at least one aquatic organism is shown. As Figure 1 shown, the imaging system includes an imaging device 5 and two mirrors 7. The two mirrors 7 are arranged to provide imaging of the aquatic organism from two angles (dual-angle system). With one imaging device, imaging of the aquatic organism can be performed from two angles. Imaging of the aquatic organism can be performed simultaneously from two angles. Imaging both sides of the aquatic organism simultaneously can increase the chance of obtaining good images of the aquatic organism that can be used for automated biometric measurements and provides the possibility of later three-dimensional reconstruction of the aquatic organism.

[0035] The imaging system has a flow cell 3 through which the aquatic organism to be imaged passes. In Figure 1 , the flow cell 3 and the mirrors 7 are arranged inside a transparent container 8. The container can be filled with a transparent material, can be filled with a degassed liquid or a transparent resin, or can be cut from a solid piece of polycarbonate, quartz, or other transparent solid material. The container can be filled with, for example, degassed fresh water or transparent mineral oil, or can be molded from a transparent resin. Figure 1 The mirrors in are arranged to provide a reflected imaging optical path from the aquatic organism in the flow cell 3, where the reflected light beams are parallel to each other when entering the imaging device 5, as Figure 1 shown. The reflected light beams are also parallel to the optical axis of the imaging device. Figure 1 The mirrors of the imaging system in can be arranged to obtain two reflected imaging optical paths from the aquatic organism that are approximately at a 90° angle to each other. In Figure 1 , each mirror is arranged at an angle of approximately 22.5° relative to a plane perpendicular to the field-of-view axis of the imaging device. The two mirrors are arranged on each side of the central axis of the field of view of the imaging device. The first mirror is as Figure 1The one shown is arranged on the left side of the central axis. The second mirror is arranged as shown in Figure 1 on the right side of the central axis. The light-gathering port (lens) of the imaging device is arranged parallel to the inner bottom of the container, as shown in Figure 1 . Therefore, the angle of the mirror of about 22.5° is also defined relative to the inner bottom of the container, as shown in Figure 1 .

[0036] Figure 1 The imaging system in may also be provided with an optional light source / illumination source for illuminating the flow cell. Figure 1 has two illumination sources. One illumination source 6 is arranged on opposite sides of the imaging device 5. The light sources are arranged to illuminate the flow cell from the upper partial area and the side. The light sources are attached to the outside of the container 8. The upper edge of the container is provided with chamfers so as to attach the light sources outside the container. In Figure 1 the shown embodiment, the light sources are symmetrically arranged or almost symmetrically arranged relative to the imaging device and are inclined downward to illuminate the flow cell from the upper partial area and the side. Light sources can be used to improve the quality of the image by increasing the contrast in the image and avoiding the appearance of shadows in the image. This increases the contrast between the aquatic organism and the surrounding water and can also increase the contrast between different parts of the aquatic organism, including the external and internal structures of transparent or partially transparent aquatic organisms. The illumination sources can be replaced individually.

[0037] In Figure 1 , at least two mirrors 7 are shown attached inside the container 8. Alternatively, the mirrors 7 can also be attached to a first frame connected inside the container. The angles of the mirrors can be fixed or set to be variable. The flow cell 3 can also be attached to a frame connected inside the container. The frame of the mirrors can be part of the same frame structure to which the flow cell is attached. However, the flow cell can also be integrated with the mirrors and the combined integrated component can be attached directly or through the frame structure inside the container. The two mirrors can also not be attached separately inside the container but be attached to each other to form a mirror unit with two reflecting surfaces. The mirror unit can also be attached to the flow cell to form a single unit. The mirror unit and the flow cell can be replaced individually, and the combined mirror and flow cell unit can also be replaced. The container with the mirror and flow cell unit can also be replaced as a unit. The imaging device and the illumination source that may be located outside the container can be easily disconnected from or connected to any container. The flow cell can also be easily disconnected from the possible flow pipe for the inflow and outflow of small aquatic organisms into and out of the flow cell inside the container. Aquatic organisms can pass through the imaging system one by one or multiple at the same time. The imaging system can image one or more aquatic organisms simultaneously.

[0038] The upper side and the lower side are only in relation to Figure 1For purposes of explanation when relevant, "up" and "down" are relative to the flow cell within the container. The mirror is arranged below the flow cell, and the imaging device is located above the upper side of the flow cell. However, the container with the imaging system can be arranged in any orientation in environments such as the ocean, fish farming sea enclosures, etc.

[0039] In Figure 1 it, the imaging device is arranged above the aquatic organism. As described above, the imaging system can be arranged in any orientation. The imaging device 5 is arranged on the first side of the aquatic organism. At least two mirrors are arranged on the second side of at least one aquatic organism, where the first side is opposite to the second side. The at least two mirrors are arranged to obtain at least two reflected imaging light paths from at least one aquatic organism, so as to provide imaging of at least one aquatic organism from at least two sides. Figure 1 The flow cell in

[0040] Figure 2 Another example of an imaging system for imaging an aquatic organism is shown. At least two mirrors and the imaging device can be arranged relative to each other to obtain images of at least one aquatic organism from three different angles (three-angle system). The images at the first angle and the second angle are formed by being reflected by at least two mirrors into the imaging device, and the image at the third angle is formed by directly imaging at least one aquatic organism into the imaging device. The imaging system has the same main components as Figure 1 explained in detail above. Figure 2 The flow cell in

[0041] has a circular cross-section. The arrangement of the flow cell, mirrors, lenses, and lights enables imaging of fish larvae from three angles using only one imaging device. Figure 2 At least two mirrors can be arranged to obtain a combined image by reflection from three different directions / angles. The three different directions are approximately 120° apart from each other (three-angle system). The images in two of the directions are formed by the aquatic organism being reflected by at least two mirrors into the imaging device. The light is reflected from the aquatic organism in the flow cell 3 to the mirror 7 and then from the mirror to the imaging device 5. The image in the third direction is formed by directly imaging the aquatic organism into the imaging device. The mirrors are arranged at different angles relative to the bottom of the cultivation pond and the plane provided by the imaging device and the lens opening. The flow cell in Figure 1 has a circular cross-section instead of the square cross-section as shown in Figure 2 The angle of the mirror relative to the inner bottom is set to 30° to create perspectives from three directions 120° apart from the aquatic organism into the imaging device 5. The reflected light beams can reach the imaging device in parallel, as shown in

[0042] Using at least two mirrors enables an imaging device to have the same focal region for a target at two viewing angles. This allows the use of an imaging device with a telecentric lens. The telecentric lens can be used for all viewing angles. The arrangement of the mirrors also makes the optical path from the aquatic organism through each mirror into the imaging device the same or substantially the same. In this way, the aquatic organism appears the same size at all viewing angles. This enables more accurate measurement of the size of the aquatic organism and / or three-dimensional reconstruction. It is desirable that the images obtained from at least two sides of the aquatic organism are symmetric or substantially symmetric.

[0043] In the above example, the mirrors are shown to have two different angles in the perspective of a plane perpendicular to the field-of-view axis of the imaging device. The field-of-view axis of the imaging device corresponds to the optical axis of the imaging device. Other angles are also possible. Each mirror can also be arranged at an angle between approximately 15° and 45° with respect to a plane perpendicular to the field-of-view axis of the imaging device. The angle of the mirror is more preferably in the range of approximately 25° to 35°. The mirrors can be arranged symmetrically or approximately symmetrically with respect to a plane perpendicular to the field-of-view axis of the imaging device.

[0044] A mirror may be an object with a reflective material coated on its surface, which can reflect a clear and detailed image of an object.

[0045] Figure 3 An imaging system for imaging an aquatic organism is shown. The imaging system includes an imaging system arranged for imaging fish larvae in a flow-through tank. The imaging device is arranged above the flow-through tank. The imaging system is provided with two light sources to illuminate the flow-through tank. These two light sources are arranged on opposite sides of the imaging device. As Figure 1 shown, two mirrors are arranged below the flow-through tank. Each mirror is arranged at an angle with respect to the longitudinal direction of the flow-through tank or the plane provided by the lens opening of the imaging device 5. The mirrors are arranged to provide two mutually opposite reflective imaging optical paths so that the aquatic organism can be imaged from two directions / sides. Imaging can be performed simultaneously from two angles. At least two sides of the aquatic organism can be at an angle of approximately 90° to each other. Figure 2 The mirrors, flow-through tank, imaging device, and lighting device in the embodiments can be applied to Figure 3 , to replace Figure 1 the example configurations of the mirrors, flow-through tank, imaging device, and lighting device in Figure 2 . In the example, if the imaging system in Figure 3 is applied to , three different directions can be at an angle of approximately 120° to each other (triangular angle system). Further embodiments of imaging the aquatic organism from more than three angles can also be envisaged. The arrangement of the flow-through tank, mirrors, lens, and lights enables imaging of the fish larvae from at least two angles using only one camera. Imaging the aquatic organism from at least two directions can be performed simultaneously or almost simultaneously.

[0046] Figure 3 An imaging system, a computer 9, and a power supply 10 are shown. The computer can control the imaging system with an imaging device and a flow cell. The computer 9 can also optionally control the flow of aquatic organisms through the flow cell. However, the flow of aquatic organisms through the flow cell can be controlled, for example, by a separate control device or, for example, by natural flow. The computer can also store imaging data and analyze the imaging data acquired by the imaging device 5. Image analysis can also be performed at a remote location. The imaging system can be provided with a transmitter for transmitting the imaging data to a remote location almost in real time. The imaging system can also be provided with an interface for later downloading the imaging data acquired by the imaging device. The imaging system can also be provided with an interface for external communication with the imaging device. The external communication with the imaging device can be carried out on site, for example, also at an underwater location.

[0047] Figure 3 The imaging system in [description] includes an imaging device, a flow cell, a mirror, a lighting device, a computer, and a power supply, all of which are arranged inside a container. The container can be transparent and can be filled with a transparent material. For example, the container can be filled with a degassed liquid or a transparent resin. The transparent material can eliminate optical distortions caused by the irregularities of the flow cell. Figure 3 The imaging device 5 in [description] is attached to the inner wall of the container. The mirror, the flow cell, and the lighting device are attached to the inner bottom of the container. The imaging device can be a camera, such as an infrared camera, an ultraviolet wavelength camera, a camera in the visible light wavelength range, or a camera with a combination of ultraviolet and visible light wavelengths. The camera can record one image at a time or record a video. The light source can be in the visible light wavelength range or can emit light in the ultraviolet wavelength range. Some aquatic organisms may emit fluorescence when irradiated by the lighting device, and this fluorescence emitted by the aquatic organisms can be detected by the imaging device. At least two lighting sources 6 and at least two mirrors 7 are arranged outside the flow cell 3. The flow cell can be made of a transparent material, such as polycarbonate, quartz, plastic. The transparent material enables imaging of aquatic organisms without removing them from the water. Figure 3 The flow cell shown in [description] has a square cross-sectional shape. Figure 3The flow cell therein is arranged such that two adjacent longitudinal sides of its upper part face two light sources respectively, so that at least part of the light from the light sources can directly pass through the flow cell without refraction. The light sources are designed to illuminate the aquatic organisms from various angles, where some of the light directly irradiates on the aquatic organisms, and some of the light illuminates the aquatic organisms through the mirror 7, thereby obtaining an image with clear contrast and clear contour boundaries. The light then enters the imaging device 5. At least part of the light reflected by the mirror 7 can directly enter the imaging device 5. The flow cell can be provided with a light diffuser on the outer side of at least part of its side walls (preferably on the side wall of the flow cell facing the light source), so as to scatter the light entering the flow cell, thereby providing a softer lighting condition for imaging the larvae of fish.

[0048] The imaging device and at least two illumination sources can also be arranged outside the container. In addition, the computer and the power supply can also be arranged outside the container.

[0049] In Figure 3 each mirror is arranged at an angle of about 22.5° with respect to the longitudinal direction of the flow cell / the inner bottom of the container / the imaging plane of the imaging device lens. These mirrors can also be arranged at other angles, such as at an angle of 30° with respect to the longitudinal direction of the flow cell. In Figure 3 at least two mirrors 7 and the imaging device 5 can be arranged relative to each other to obtain images of the aquatic organisms in the flow cell from at least two different directions. The images in the first direction and the second direction are respectively provided by the reflection imaging optical paths of the first mirror and the second mirror. If the mirror and the flow tube settings in Figure 2 are used, the image in the third direction can be formed by directly imaging the aquatic organisms onto the imaging device. At this time, the mirrors can be arranged at an angle of about 120° relative to each other, for example. The flow cell may also be of other shapes, such as rectangular, oval or circular.

[0050] The design of the flow cell and the flow system will not cause harm to the aquatic organisms. Additional light sources can also be added to improve the images of the aquatic organisms. The additional light sources can increase the contrast and reduce the shadow effect in the images. The light sources are arranged such that the aquatic organisms can be imaged from at least two sides.

[0051] The camera, the mirror and the light source are arranged outside the flow cell. This provides flexibility for the arrangement of the camera, the mirror and the light source, taking into account both the flow cell and their mutual arrangement. As described above, the mirrors can be arranged at different angles to adapt to the actual flow cell used and the system requirements. The arrangement outside the flow cell also provides greater flexibility for replacing the camera, the mirror and the light source for repair or replacement, or for replacing one or all of the camera, the mirror and the light source to adapt to a specific flow cell. The size and / or shape of the flow cell, the camera and / or mirror used can be adjusted according to the aquatic organisms of different sizes.

[0052] The imaging system may also be provided with instruments for storing and processing data. Automatic image processing for biometric measurements may be provided. Figure 3 It can be implemented as an ex-situ imaging system, providing an "all-in-one" system capable of performing imaging and image analysis simultaneously. The processing can be carried out in real time or completed by post-processing the data.

[0053] Figure 4 An imaging system associated with a cultivation tank 2 containing aquatic organisms (such as fish larvae, zebrafish larvae, zooplankton) is shown. To image the aquatic organisms, the aquatic organisms are made to flow out of the cultivation tank and into the imaging system 1 through, for example, a pipe or a flow-through tube. In the imaging system, the aquatic organisms are imaged as they pass through the imaging system. The imaging system is suitable for specific uses and the aquatic organisms in the cultivation tank. In addition to Figure 1 or Figure 2 the components of the imaging system shown, Figure 4 the imaging system in may also be provided, for example, with a valve for flow rate regulation and optionally with a triggering system for the imaging system. The triggering system can detect the aquatic organisms before they reach the imaging system and activate the imaging system at an appropriate time so that the aquatic organisms are centered in the image when passing through the flow-through tube imaging system for imaging. The flow-through tube is provided with an imaging system with a flow-through cell for imaging each aquatic organism as it passes through the flow-through cell. The imaging system can image the aquatic organisms from two or more angles. Imaging from two or more angles can be carried out simultaneously. Multiple aquatic organisms can be imaged simultaneously. After passing through the imaging system, at least one aquatic organism continues to be conveyed along the flow-through tube and into the cultivation tank, as Figure 4 shown. The imaging system is a flow-through imaging system. The flow-through tube is designed to convey the aquatic organisms through the imaging system with a flow-through cell. The aquatic organisms can be conveyed through the flow-through cell one by one or multiple at a time through the imaging system.

[0054] The aquatic organisms may also enter a second cultivation tank after passing through the flow-through imaging system. Valves may be provided on the flow-through tube to control the flow rate of the aquatic organisms through the flow-through tube and the imaging system. The flow rate should be adjusted so that the aquatic organisms pass through the imaging system at a slow enough speed to be imaged one by one by the imaging system. In addition, simultaneous imaging of multiple aquatic organisms can also be achieved.

[0055] Figure 4 This is only a schematic diagram, and there may be other cultivation tank configurations. The flow-through tube may eventually be immersed in water. In some embodiments, the aquatic organisms may fall into the second cultivation tank. Considering the second cultivation tank, the first cultivation tank may be in an elevated position so that the aquatic organisms flow from the first cultivation tank into the second cultivation tank under the action of gravity.

[0056] When the aquatic organisms are taken out of the cultivation tank and enter the flow-through pipe at a liquid level higher than the return liquid level of the flow-through pipe, in the Figure 4 system, it is also provided to use gravity to convey the aquatic organisms through the Figure 4 flow-through imaging system in

[0057] Embodiment

[0058] Figure 5a An embodiment of an imaging system is shown, which uses a flow-through cell in an experimental configuration to obtain images of fish larvae, as Figure 6 shown. Figure 5a It may illustrate a schematic diagram of an experimental configuration of an imaging system designed according to the component dimensions and positions in the component data sheets. The trigger system shown is only optional. Figure 5a The imaging system in

[0059] In Figure 5a the shown embodiment, the flow-through cell has a square cross-section with an inner width of 4 mm and a length of approximately 300 mm. The flow-through cell and the mirror are arranged inside a container filled with liquid. The mirror used is a 50×75 mm enhanced aluminum 4-6λ mirror from Edmund Optics. Two lighting sources are arranged outside the container. More details of the flow-through cell will be shown and explained later in the Figure 5b magnified view. The camera used is a FLIR Grashopper 3 5MP camera, equipped with a TechSpec 0.5× telecentric lens, with a width W of 17.6 mm, a height H of 13.2 mm, and a total ratio of 139 pixels per mm. The camera is powered by a 24VDC power supply. In terms of lighting, MicroBrite is adopted TMThe 2×AL295 LED lighting unit of Bar Lights brand, with a total power of 80W (overload power 800W), enables the lens to adopt the lowest aperture value through sufficient light intensity, thereby obtaining the maximum depth of field and ensuring that the entire volume of the flow cell can be focused. The AL295 lamp used is 89.4 mm in length and emits white light (5500K to 6100K). The camera is connected to a Raspberry Pi 4 running custom software for setting the correct camera parameters and capturing and storing images from the camera. The Raspberry Pi 4 is powered by a 5VDC power supply. Images are automatically stored on a 128GB memory card. The speed of the larvae passing through is adjusted by a flow valve (not shown). All components are attached to two 10-mm high-density polyethylene (HDPE) plates through a support structure. A funnel is connected to the flow cell using a silicone tube.

[0060] Figure 5b A detailed sketch of the flow cell and the mirror is shown from the side and the front, where the container is filled with degassed water. The flow cell is a square quartz tube with an inner width of 4 mm and a length of approximately 300 mm. Two mirrors are arranged at an angle of approximately 22.5° about 11 mm below the flow cell to achieve two reflection imaging optical paths arranged at 90° to each other. The mirrors and the flow cell are located inside a waterproof container filled with degassed water to eliminate optical distortion caused by the irregularity of the flow cell. The container is made of Lexan. The container can also be filled with, for example, transparent mineral oil. The optical system and the flow cell are optimized for larvae with a length of 3 - 10 mm and a maximum diameter of 4 mm. Figure 5a

[0061] Figure 6 Figure 5a Three images of the same larva taken using the imaging system described above and shown in 5b and Figure 6 are shown. The fish larvae in

[0062] are newly hatched zebrafish larvae. Approximately 300 newly hatched zebrafish larvae flow through the imaging system in a water volume of about 1 deciliter. The images on the left and right sides are taken through the mirrors on the right and left sides and are rotated 90° to each other. The middle image is taken directly from the zebrafish larvae inside the flow cell. It can be seen from the images that the visibility of the yolk of the zebrafish larvae is different in the images. In addition, in one image, the zebrafish larva is quite straight, while in another image, the tail is curved. By obtaining images from multiple sides, the opportunity to measure, for example, the zebrafish larvae, such as morphometric measurements, is increased. The yolk can be measured from an image with a visible yolk, while the length can be measured from another image. This enables more accurate measurement of the size of the yolk and other parameters of the zebrafish larvae, such as length.An exemplary imaging system is explained for ex vivo imaging of fish larvae. The imaging system can also be an in vivo system. Additionally, as previously mentioned, the imaging system can also be used for imaging other small aquatic organisms, such as small fish, fish larvae, algae, crustaceans, zooplankton, or eggs of aquatic organisms. The imaging system can be used to monitor the size or growth status of small aquatic organisms. The imaging system can also be used to construct three-dimensional images of small aquatic organisms, perform morphometric measurements on small aquatic organisms, monitor the growth status of fish larvae, monitor the health status of fish larvae, or perform biometric measurements on fish larvae, or monitor fish larvae in a production pond.

[0063] After describing the exemplary embodiments of the present invention, it will be apparent to those skilled in the art that other embodiments incorporating these concepts can be used. The above and other non-limiting embodiments are provided by way of example only, and the actual scope of the present invention should be determined by the following claims.

Claims

1. An imaging system for imaging at least one aquatic organism, the imaging system comprising: an imaging device, and at least two mirrors, wherein the mirrors are arranged to provide imaging of the at least one aquatic organism from at least two angles.

2. The imaging system according to claim 1, further comprising at least two illumination sources.

3. The imaging system according to claim 1 or 2, wherein, the imaging device is arranged on a first side of the at least one aquatic organism, and the at least two mirrors are arranged on a second side of the at least one aquatic organism, wherein the first side is opposite to the second side.

4. The imaging system according to any one of claims 1 - 3, wherein, the at least two mirrors are arranged to obtain at least two reflected imaging light paths from the at least one aquatic organism.

5. The imaging system according to any one of claims 1 - 4, wherein, the at least two mirrors and the imaging device are arranged to obtain a combined image of the at least one aquatic organism from three different angles, wherein the images at the first and second angles are formed by the at least one aquatic organism entering the imaging device after being reflected by the at least two mirrors, and the image at the third angle is formed by the at least one aquatic organism directly imaging onto the imaging device.

6. The imaging system according to any one of claims 1 - 5, wherein, each of the at least two mirrors is arranged at an angle with respect to a plane perpendicular to the field - of - view axis of the imaging device, and the angle is about 15° to 45°.

7. The imaging system according to any one of claims 1 - 6, wherein, each of the at least two mirrors is arranged at an angle of approximately 22.5° with respect to a plane perpendicular to the field - of - view axis of the imaging device, so as to obtain two reflected imaging light paths from the aquatic organism that are approximately at an angle of 90° to each other.

8. The imaging system according to any one of claims 1 - 6, wherein, each of the at least two mirrors is arranged at an angle of approximately 30° with respect to a plane perpendicular to the field - of - view axis of the imaging device.

9. The imaging system according to any one of claims 1 - 8, wherein, at least two illumination sources are arranged on opposite sides of the imaging device.

10. The imaging system according to any one of claims 1 - 6 and 8 - 9, wherein, the at least two mirrors are arranged to obtain a combined image of the at least one aquatic organism provided by three different - angle perspectives, the three different perspectives being at an angle of 120° to each other, wherein the images at two angles are formed by the aquatic organism entering the imaging device after being reflected by the at least two mirrors, and the image at the third angle is formed by the aquatic organism directly imaging into the imaging device.

11. The imaging system according to any one of claims 1 - 10, wherein, the at least two mirrors are arranged symmetrically or approximately symmetrically with respect to the field - of - view axis of the imaging device.

12. The imaging system according to any one of claims 1 - 11, wherein, The at least two mirrors are arranged such that the imaging device has the same focal region at each viewing angle.

13. The imaging system according to any one of claims 1-12, wherein, the imaging device includes a telecentric lens.

14. The imaging system according to any one of claims 1-13, wherein, the at least one aquatic organism is arranged to be imaged by the imaging device while flowing through the flow-through cell.

15. The imaging system according to claim 14, wherein, the flow-through cell and the at least two mirrors are arranged within a container filled with a transparent material, which is preferably a degassed liquid or a transparent resin.

16. The imaging system according to claim 15, wherein, the imaging device and at least two illumination sources are arranged inside or outside the container.

17. The imaging system according to any one of claims 14-16, wherein, the flow-through cell is transparent.

18. The imaging system according to any one of claims 15-17, wherein, the container is transparent.

19. The imaging system according to any one of claims 1-18, wherein, the container is made of polycarbonate or quartz.

20. The imaging system according to any one of claims 1-19, wherein, the flow-through cell is made of polycarbonate, quartz or plastic.

21. The imaging system according to any one of claims 14-20, wherein, the flow-through cell includes at least one light diffuser.

22. The imaging system according to any one of claims 1-21, wherein, images of at least two angles / sides of the at least one aquatic organism are acquired simultaneously.

23. A flow-through imaging system for imaging at least one aquatic organism as the at least one aquatic organism passes through a flow-through cell, the system comprising: a flow-through cell, and an imaging system according to any one of claims 1-22.

24. The flow-through imaging system according to claim 23, wherein, the flow-through cell and the at least two mirrors are arranged within a container filled with a liquid or a transparent resin to eliminate optical distortion caused by irregularities of the flow-through cell.

25. The flow-through imaging system according to claim 23 or 24, further comprising a valve for regulating the flow rate through the flow-through cell.

26. Use of the imaging system according to any one of claims 1-22 for monitoring the size or growth condition of small aquatic organisms.

27. Use of the imaging system according to any one of claims 1-22 or the flow-through imaging system according to any one of claims 23-25 for constructing a three-dimensional image of small aquatic organisms.

28. Use of the imaging system according to any one of claims 1-22 or the flow-through imaging system according to any one of claims 23-25 for morphometric measurement of small aquatic organisms.

29. Use of the flow-through imaging system according to any one of claims 23-25 for monitoring the growth of fish larvae, monitoring the health condition of fish larvae, performing biometric measurements on fish larvae or monitoring fish larvae in a production pond.

30. The use according to any one of claims 26 - 29, wherein, the small aquatic organisms are at least one of fish larvae, zebrafish larvae, algae, crustaceans, zooplankton or aquatic organism eggs.

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