Imaging systems for aquatic life

Abstract

An imaging system for imaging aquatic organisms. The imaging system includes an imaging device and at least two mirrors configured to provide images of the aquatic organisms from at least two angles. The imaging system can include two illumination sources. The imaging system can image small aquatic organisms as they pass through a flow cell.

Description

[Technical Field]

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

[0002] Observing small aquatic organisms is important for several reasons. There is growing awareness of the importance of observing marine ecosystems throughout the food chain. Preserving the oceans and marine ecosystems is important for preserving the diversity of life and nature on Earth and for providing food for a growing population. Small aquatic organisms represent an important part of the marine food chain, and observing, for example, the morphometry, growth, and density of small aquatic organisms in the ocean is of interest. For example, in fish farming, observations are important for both the larvae and the food for the larvae, such as zooplankton. Examples of observations can relate to, for example, the morphometry of small aquatic organisms, how their dimensions change over time, how aquatic organisms grow and develop, the density of aquatic organisms in aquariums or fish farming sea pens, and the classification of aquatic organisms present in the ocean or tank. It is well established that an unfavorable and toxic environment in the early stages of fish will increase the frequency of developmental malformations in the hatched larvae, which can be used in marine observations as an indicator of water quality.

[0003] As a further example, in the propagation of marine fish species, the spawning stage is the most difficult and still represents the greatest obstacle from a production standpoint. This is because the newly hatched fry are very small and the density of spawn in each tank is high. Marine fry are stunted after hatching and, unlike salmon, require good quality live feed organisms to grow and develop normally. The initial feeding period, from when the fry begin to eat until they are large enough to digest formulated feed, is often characterized by high mortality and improper development. How well the fry thrive in a fish farming environment depends on many complex factors, including feed quality, water quality, and fish egg quality.

[0004] Observing fish growth is important. Good early nutrition is crucial to how fish grow and develop later in life. Larvae are observed early to achieve predictability and profitability in later production. Larvae growth, development, and appetite (gastric fullness) are most frequently observed by removing them from the container and examining them under a magnifying glass / microscope, where measurements and records are made. Although breeders may spend two to three months a year on this task, this still provides too little information for breeders to feel it is worth the time investment. The small number of larvae does not provide a representative target for the population, and there is currently no good system for recording data. This means that groups in different containers on the same facility, or from year to year, cannot be compared. This also means that unprofitable groups are detected too late to take action. Summary of the Invention [Problem to be solved by the invention]

[0005] There is a need for a simple, cost-effective observation system for small aquatic organisms that can be easily adapted to a variety of aquatic organisms and environmental conditions. [Means for solving the problem]

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

[0007] The present invention provides an imaging system that enables imaging of small aquatic organisms from at least two angles. The imaging system includes an imaging device and at least two mirrors configured 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. The at least one aquatic organism can be imaged while at least one larva passes through a flow cell. The flow-through imaging system can include a flow cell and an imaging system according to the above. The present invention also provides an imaging system and a use of the flow-through imaging system.

[0009] The present invention provides an imaging system for imaging at least one aquatic organism, the imaging system comprising an imaging device and at least two mirrors configured to provide images of the at least one aquatic organism from at least two angles.

[0010] The imaging system may further include at least two illumination sources. The at least two illumination sources may be positioned on either side of the imaging device. The imaging device may be positioned on a first side of the at least one aquatic organism, and the at least two mirrors may be positioned on a second side of the at least one aquatic organism, the first side being opposite the second side. The at least two mirrors may be configured to obtain at least two reflections from the at least one aquatic organism. The at least two mirrors and the imaging device may be configured to obtain combined images of the at least one aquatic organism from three different angles, the first and second angles being provided by reflections from the at least one aquatic organism onto the imaging device using the at least two mirrors, and the third angle being provided by a direct image of the at least one aquatic organism onto the imaging device.

[0011] The at least two mirrors may each be positioned at an angle relative to a plane perpendicular to the axis of the field of view of the imaging device, the angle being between about 15° and 45°.

[0012] The at least two mirrors are positioned at approximately 22.5° relative to a plane perpendicular to the axis of the field of view of the imaging device to obtain two reflections from the aquatic organism at approximately 90° relative to each other. Alternatively, each of the at least two mirrors can be positioned at an angle of approximately 30° relative to the plane perpendicular to the axis of the field of view of the imaging device. The at least two mirrors can be configured to obtain a combined image of the at least one aquatic organism provided by fields of view from three different angles, the three different fields of view being at angles of 120° relative to each other, two of which are reflections from the aquatic organism to the imaging device via the at least two mirrors, and the third angle is a direct image of the aquatic organism to the imaging device. The at least two mirrors can be positioned symmetrically or nearly symmetrically relative to the axis of the field of view of the imaging device. The at least two mirrors can be configured to enable the same focal area of ​​the imaging device for each field of view. The imaging device can include a telecentric lens. Images of at least two angles / sides of the at least one aquatic organism can be obtained simultaneously.

[0013] The at least one aquatic organism can be configured to flow through the flow cell while being imaged by the imaging device. The flow cell and the at least two mirrors can be disposed inside a container filled with a transparent material. The container can be filled with a degassed liquid or a transparent resin. The imaging device and the at least two illumination sources can be disposed inside or outside the container. The flow cell and container can be transparent. The container can be made from polycarbonate or quartz. The flow cell can be made from polycarbonate, quartz, or plastic. The flow cell can further include at least one optical diffuser.

[0014] The present invention also provides a flow-through imaging system for imaging at least one aquatic organism while the at least one aquatic organism passes through a flow cell. The system includes a flow cell and an imaging system. The imaging system is as described above. The flow cell and at least two mirrors may be disposed inside a container filled with a liquid or transparent resin to eliminate optical distortion caused by irregularities in the flow cell. The flow-through imaging system may further include a valve for regulating flow through the flow cell.

[0015] The present invention also provides a use of the imaging system for observing the size or growth of small aquatic organisms. The imaging system or flow-through imaging system can also be used to construct 3D images of small aquatic organisms or for morphometric measurements of small aquatic organisms. The flow-through imaging system can also be used to observe the growth of larval fish, observe the health of larval fish, perform biological measurements of larval fish, or observe larval fish in production tanks. The small aquatic organisms can be at least one of larval fish, zebrafish larvae, algae, crustaceans, zooplankton, or eggs from aquatic organisms.

[0016] The imaging system provides a flexible solution for imaging aquatic organisms. The imaging system can be easily scaled to image aquatic organisms of different sizes and shapes, and to accommodate mutual configurations between the system's components. The imaging device, mirror, and possible light source can be configured independently of each other and can be positioned close to or far apart. The mirror can have various areas and shapes, as long as the imaging system's ability to image aquatic organisms from at least two angles is maintained. An imaging system positioned externally to a possible flow cell allows flexibility regarding the size, shape, and mutual configuration of the imaging device, mirror, and possible light source, for example, as described above. An imaging system with or without a flow cell also allows for easy replacement or repair of individual components of the system. A mirror and flow cell positioned inside a container also allows for easy replacement of the container with the flow cell and mirror to adapt the imaging system for different applications, such as for observing other aquatic organisms, or the mirror and flow cell can be easily replaced if damaged or worn. A new container can be easily connected to an illumination source and imaging device, which can be positioned inside or outside the container.

[0017] The imaging system can also be easily adapted for a variety of applications, such as in the ocean, in fish farming, or in closed systems both at sea and on land. The imaging system can be used, for example, to establish algae density in the ocean, to classify algae in the ocean, to measure morphometrics of crustaceans in the open ocean, to establish larval growth, larval quality, to measure length relative to yolk sac dimensions, to identify any deformations in the larvae, etc. Another use is to observe the production of live food, for example, zooplankton, larvae, algae, and eggs, where morphometric measurements can establish growth, density, quality, etc.

[0018] By way of example only, the imaging system can enable automatic imaging and analysis of larval fish. Larval fish can be removed, for example, from a fish tank and passed through a flow cell and allowed to flow through the imaging system. Images of the larvae can be analyzed using machine learning. An imaging system with a flow cell enables automatic biometric measurements of the larvae. Images can be analyzed in real time. The images also allow for subsequent 3D reconstruction of the larvae. A flow-through imaging system provides an effective and more accurate system for imaging large numbers of larval fish without affecting their health and viability. Thus, the system can be used for repeated analysis of the same group of larvae over time. The above example for larval fish can also be applied to other small aquatic organisms. While the imaging system is for imaging small aquatic organisms, such as those illustrated in this application, it can also be applied to minnows and other small, living aquatic organisms.

[0019] Exemplary embodiments will now be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram of an exemplary imaging system for imaging at least one aquatic organism from two angles. [Figure 2] FIG. 10 is a diagram of another exemplary imaging system for imaging at least one aquatic organism from three angles. [Figure 3] 1 is a diagram of an exemplary imaging system for imaging at least one aquatic organism from two angles. [Figure 4] FIG. 1 is a diagram of an exemplary imaging system configured for an aquatic tank to observe aquatic life within the tank. [Figure 5a] FIG. 1 is a schematic diagram of an exemplary imaging system for imaging larval fish. [Figure 5b]5b is a schematic diagram of an exemplary imaging system for imaging the larval fish from FIG. 5a, showing the imaging device, mirror, flow cell, and illumination source in side and front views. [Figure 6] 5a and 5b. The zebrafish larvae images on the left and right are taken with the right and left mirrors and are rotated 90° relative to each other. The middle image was acquired directly with the larvae inside the flow cell. DETAILED DESCRIPTION OF THE INVENTION

[0021]

[0013] Exemplary embodiments are described with reference to the drawings. The same reference numerals are used in all drawings and throughout this description for the same or similar features. The examples are illustrative only and are not limiting of the invention.

[0022] An imaging system 1 for imaging at least one aquatic organism is shown in FIG. 1. As shown in FIG. 1, the imaging system includes an imaging device 5 and two mirrors 7. The two mirrors 7 are configured to provide imaging of the aquatic organism from two angles (a two-angle system). Imaging of the aquatic organism from two angles is performed using one imaging device. Imaging of the aquatic organism from two angles can be performed simultaneously. Imaging both sides of the aquatic organism simultaneously increases the chances of obtaining good images of the aquatic organism, which can be used for automatic biometry and also offers the possibility of later 3D reconstruction of the aquatic organism.

[0023] The imaging system includes a flow cell 3 through which the aquatic organisms to be imaged flow. In FIG. 1, the flow cell 3 and mirror 7 are positioned inside a transparent container 8. The container can be filled with a transparent material. The container can be filled with a degassed liquid or a transparent resin. The container can also be cut from a solid piece of polycarbonate, quartz, or other transparent solid material. The container can be filled with, for example, degassed freshwater or transparent mineral oil. The container can also be molded from a transparent resin. The mirrors in FIG. 1 are positioned to provide reflections from the aquatic organisms in the flow cell 3, where the reflected light rays are parallel to each other when they enter the imaging device 5, as shown in FIG. 1. The reflected light rays are also parallel to the optical axis of the imaging device. The mirrors in FIG. 1 of the imaging system can be configured to obtain two reflections from the aquatic organisms at approximately 90° to each other. In FIG. 1, each of the mirrors is positioned at an angle of approximately 22.5° relative to a plane perpendicular to the axis of the field of view of the imaging device. Two mirrors are positioned on either side of the central axis of the field of view of the imaging device. The first mirror is positioned to the left of the central axis as shown in Figure 1. The second mirror is positioned to the right of the central axis as shown in Figure 1. The optical opening (lens) of the imaging device is positioned parallel to the inside bottom of the container as shown in Figure 1. A mirror angle of approximately 22.5° is therefore also defined relative to the inside bottom of the container as shown in Figure 1.

[0024] The imaging system of FIG. 1 can also include an optional light / illumination source for illuminating the flow cell. FIG. 1 shows two illumination sources. One illumination source 6 is positioned opposite the imaging device 5. The light source is positioned to illuminate the flow cell partially from above and from the side. The light source is attached to the outside of the container 8. The container has a corner cut into the upper edge of the container to mount the light source to the outside of the container. In the embodiment shown in FIG. 1, the light source is positioned symmetrically or nearly symmetrically with respect to the imaging device and is tilted downward to illuminate the flow cell partially from above and from the side. The use of a light source can improve image quality by increasing image contrast and avoiding image shadows. This can improve the contrast between the aquatic organism and the surrounding water and between various parts of the aquatic organism, both in the external and internal structures of transparent or partially transparent aquatic organisms. The illumination sources can be separately replaceable.

[0025] In FIG. 1 , at least two mirrors 7 are shown mounted inside the vessel 8. Alternatively, the mirrors 7 can also be mounted on a first frame mounted inside the vessel. The angle of the mirrors can be fixed or variably positioned. The flow cell 3 can also be mounted on a frame mounted inside the vessel. The frame for the mirrors can be part of the same frame structure to which the flow cell is mounted. However, the flow cell can also be integrated with the mirrors, and the combined integrated part can be mounted inside the vessel directly or via a frame structure. The two mirrors do not have to be separately mounted inside the vessel, but can be attached to each other to form a mirror unit with two reflective mirror surfaces. The mirror unit can also be attached to the flow cell to form a single unit. The mirror unit and flow cell can be separately replaceable, or the combined mirror and flow cell unit can also be replaceable. The vessel with the mirror and flow cell unit can also be replaced as a single unit. The imaging device and possible illumination source outside the vessel can be easily detached from and connected to any vessel. The flow cell can also be easily detached from a possible flow tube for transferring small aquatic organisms into and out of the flow cell inside the container. The aquatic organisms can be transported through the flow cell one at a time or many at a time and past the imaging system. The imaging system can image one or more aquatic organisms at a time.

[0026] With respect to Figure 1, the terms "upper" and "lower" are used for illustrative purposes only, and are viewed with respect to the flow cell inside the vessel. The mirror is located below the flow cell, and the imaging device is located above the upper side of the flow cell. However, the vessel with the imaging system can be located in any orientation, such as in the ocean, in a fish cage, etc.

[0027] In FIG. 1, the imaging device is positioned above the aquatic organism. As previously mentioned, the imaging system can be positioned in any orientation. The imaging device 5 is positioned on a first side of the aquatic organism. At least two mirrors are positioned on a second side of the at least one aquatic organism, the first side being opposite the second side. The at least two mirrors are positioned to obtain at least two reflections from the at least one aquatic organism, providing imaging of the at least one aquatic organism from at least two sides. While the flow cell in FIG. 1 is shown as having a square cross-section, other shapes are also possible.

[0028] FIG. 2 shows another example of an imaging system for imaging aquatic organisms. At least two mirrors and an imaging device can be mutually configured to acquire images of at least one aquatic organism from three different angles (a three-angle system). The first and second angles are provided by reflections from the at least two mirrors to the imaging device, and the third angle is provided by an image from the at least one aquatic organism to the imaging device. The imaging system has the same major components as FIG. 1, as described in detail above. The flow cell in FIG. 2 has a circular cross-section. The configuration of the flow cell, mirrors, lenses, and light allows for imaging of larval fish from three angles using only one imaging device.

[0029] At least two mirrors can be configured to capture a combined image provided by reflections from three different directions / angles. The three different directions can be at angles of approximately 120° relative to each other (a three-angle system). Two of the directions are reflections from the aquatic organism to the imaging device via at least two mirrors. Light is reflected from the aquatic organism inside the flow cell 3 to mirror 7 and then from the mirror to the imaging device 5. The third direction is a direct image of the aquatic organism to the imaging device. The mirrors are positioned at different angles relative to the bottom of the tank and, thereby, to the plane provided by the imaging device and lens opening. The flow cell has a circular cross-section in FIG. 2 rather than a square cross-section as in FIG. 1. The mirrors are angled 30° relative to the inside bottom, creating viewing angles of the aquatic organism to the imaging device 5 from three directions separated by 120°. The reflected light rays reach the imaging device parallel as shown in FIG. 2, providing a single combined image from the three viewing angles.

[0030] The use of at least two mirrors allows the imaging device to have the same focal area of ​​the objective lens for both viewing angles. This allows the use of an imaging device with a telecentric lens, which can be used for all viewing angles. The mirror configuration also ensures that the light travels the same or substantially similar path from each mirror from the aquatic organism to the imaging device. The aquatic organism will then appear to have the same dimensions for all viewing angles. This allows for more accurate dimensional measurement and / or 3D reconstruction of the aquatic organism. It is desirable that the images acquired from at least two sides of the aquatic organism be symmetrical or substantially symmetrical.

[0031] In the above example, the mirrors are shown with two different angles relative to a plane perpendicular to the axis of the field of view of the imaging device. The axis of the field of view of the imaging device corresponds to the optical axis of the imaging device. Other angles are possible. Each of the mirrors can also be positioned at an angle of approximately 15° to 45° relative to the plane perpendicular to the axis of the field of view of the imaging device. More preferably, the angle relative to the mirror is in the range of approximately 25° to 35°. The mirrors can be positioned symmetrically or nearly symmetrically relative to the plane perpendicular to the axis of the field of view of the imaging device.

[0032] A mirror can be a surface coated with a reflective material that can reflect a clear, detailed image of an object.

[0033] FIG. 3 illustrates an imaging system for imaging aquatic organisms. The imaging system includes an imaging device configured to image larval fish inside a flow cell. The imaging device is positioned above the flow cell. The imaging system includes two light sources that illuminate the flow cell. The two light sources are positioned on either side of the imaging device. Two mirrors are positioned below the flow cell, as shown in FIG. 1. Each of the mirrors is positioned at an angle relative to the longitudinal direction of the flow cell or to a plane provided by the lens opening of the imaging device 5. The mirrors are configured to provide two reflections relative to each other, so that the aquatic organism can be imaged from two directions / sides. The imaging from the two angles can be performed simultaneously. At least two sides of the aquatic organism can be at approximately 90° to each other. The mirrors, flow cell, imaging device, and illumination device from the example of FIG. 2 can be implemented in FIG. 3 in place of the exemplary configuration of mirrors, flow cell, imaging device, and illumination device from FIG. 1. In the example where the imaging system from Figure 2 is implemented in Figure 3, the three different directions can be at angles of about 120° relative to each other (a three-angle system). Additional embodiments that image aquatic organisms from more than three angles can also be contemplated. The configuration of the flow cell, mirrors, lenses, and light allows for imaging of larval fish from at least two angles using only one camera. Imaging of aquatic organisms from at least two directions can occur simultaneously or nearly simultaneously.

[0034] FIG. 3 shows an imaging system, further including a computer 9 and a power supply 10. The computer can control the imaging system, which includes an imaging device and a flow cell. The computer 9 can also optionally control the throughflow of the aquatic organisms through the flow cell. However, the throughflow of the aquatic organisms through the flow cell can be controlled, for example, by a separate control device, or can be performed by natural flow, for example. The computer can also store and analyze imaging data obtained using the imaging device 5. Image analysis can also be performed at a remote location. The imaging system can include a transmitter for transmitting imaging data to a remote location in near real time. Alternatively, the imaging system can also include an interface for later downloading imaging data obtained by the imaging device. The imaging system can also include an interface for external communication with the imaging device. External communication with the imaging device can also be performed in situ, for example, underwater.

[0035] The imaging system in FIG. 3, including the imaging device, flow cell, mirror, lighting device, computer, and power supply, is placed inside the vessel. The vessel can be transparent. The vessel can be filled with a transparent material. The vessel can be filled with, for example, a degassed liquid or a transparent resin. The transparent material can eliminate optical distortions caused by irregularities in the flow cell. The imaging device 5 in FIG. 3 is attached to the inner wall of the vessel. The mirror, along with the flow cell and lighting device, is attached to the inside bottom of the vessel. The imaging device can be, for example, an infrared camera or a camera operating in UV wavelengths, or a camera operating in the visible wavelength range or a combination of UV and visible wavelengths. The camera can record images one by one, but can also record video. The lighting source can be in the visible part of the wavelength range, but can also emit light in the UV wavelength range. Some aquatic organisms can emit fluorescence when illuminated by the lighting device, and the fluorescence emitted by the aquatic organisms is detected by the imaging device. At least two illumination sources 6 and at least two mirrors 7 are positioned outside the flow cell 3. The flow cell can be made of a transparent material, such as polycarbonate, quartz, or plastic. Transparent materials allow imaging of aquatic organisms without removing them from the water. The flow cell shown in FIG. 3 has a square cross-sectional shape. The flow cell in FIG. 3 is configured such that each of two adjacent upper longitudinal sides facing the two light sources allows at least a portion of the light from the light sources to pass directly through the flow cell without being refracted. The light sources illuminate the aquatic organisms from all angles, meaning that some light directly illuminates the organisms and some light illuminates them through the mirrors 7, providing an image with clear contrast and distinct silhouette boundaries. The light then enters the imaging device 5. At least some other portion of the light reflected by the mirrors 7 can travel directly to the imaging device 5.The flow cell can include an optical diffuser on at least some of the exterior sides of the flow cell, preferably the sides of the flow cell facing the light source, to scatter light entering the flow cell and provide soft light for imaging the larvae. The imaging device and at least two illumination sources can also be located outside the vessel. Additionally, a computer and power supply can be located outside the vessel.

[0036] In FIG. 3, each of the mirrors is positioned at an angle of approximately 22.5° relative to the longitudinal direction of the flow cell / the inner bottom of the container / the imaging plane of the lens of the imaging device. The mirrors can also be positioned at other angles, such as 30°, relative to the longitudinal direction of the flow cell. In FIG. 3, at least two mirrors 7 and the imaging device 5 can be configured relative to each other to capture images of the aquatic organisms in the flow cell from at least two different directions. The first and second directions are provided by reflections from the first and second mirrors, respectively. The third direction can be provided by a direct image of the aquatic organisms onto the imaging device when the mirror and flow tube configuration from FIG. 2 is used. In that case, the mirrors can be positioned at, for example, approximately 120° relative to each other. Other shapes of the flow cell, such as rectangular, oval, or circular, are also possible.

[0037] The flow cell and flow system are designed to be harmless to aquatic organisms. An additional light source can also be provided to enhance the image of the aquatic organism. The additional light source can increase contrast in the image and reduce the effect of shadows. The light source is configured to allow imaging of the aquatic organism from at least two sides. The camera, mirror, and light source are positioned outside the flow cell. This allows flexibility in the configuration of the camera, mirror, and light source relative to the flow cell and their mutual configuration. The mirror can be positioned at various angles, as described above, to suit the actual flow cell and system requirements used. The external configuration outside the flow cell also provides increased flexibility for replacing the camera, mirror, and light source for repair or replacement, or for replacing one or all of the camera, mirror, and light source to suit a particular flow cell. The dimensions and / or shape of the flow cell, the camera used, and / or the mirror used can be adapted to aquatic organisms with different dimensions. The imaging system can also include devices for data storage and processing. Automatic image processing for biometric measurements can be provided. Figure 3 can be implemented as an ex-situ imaging system, providing an "all-in-one" system that allows both image capture and analysis. Processing can be performed in real time or by post-processing of the data.

[0038] FIG. 4 shows an imaging system configured for a tank 2 containing aquatic organisms, such as fish larvae, zebrafish larvae, and zooplankton. To image the aquatic organisms, they are directed out of the tank through, for example, a pipe or flow tube into the imaging system 1. In the imaging system, the aquatic organisms are imaged as they pass through the imaging system. The imaging system is adapted to the specific application and the aquatic organisms in the tank. In addition to the imaging system components shown in FIG. 1 or FIG. 2, the imaging system of FIG. 4 can also include, for example, a valve for flow regulation and, optionally, a trigger system for the imaging system. The trigger system can detect aquatic organisms before they reach the imaging system and activate the imaging system in a timely manner to capture images of the aquatic organisms in the center of the image as they pass through the flow tube imaging system. The flow tube includes an imaging system having a flow cell for capturing images of each aquatic organism as it passes through the flow cell. The imaging system can capture images of the aquatic organisms from two or more angles. The imaging from two or more angles can be performed simultaneously. Multiple aquatic organisms can be captured simultaneously. After passing through the imaging system, the at least one aquatic organism further passes through a flow tube into a tank, as shown in FIG. 4. The imaging system is a flow-through imaging system. The flow tube is designed to provide transport of the aquatic organisms through the imaging system, which includes a flow cell. The aquatic organisms can be transported through the imaging system one at a time or many at a time through the flow cell.

[0039] Alternatively, the aquatic organisms can pass through the flow-through imaging system and then end up in a second tank. A valve on the flow tube can be provided to control the flow rate of the aquatic organisms through the flow tube and the imaging system. The flow rate should be adapted so that the aquatic organisms can be transported through the imaging system slowly enough to be imaged one by one by the imaging system. It is also possible to image several aquatic organisms together.

[0040] 4 is merely an example, and other tank configurations may be possible. The flow tube is ultimately submerged in water. In some embodiments, the aquatic organisms fall into a second tank. The first tank may be elevated relative to the second tank to allow the aquatic organisms to flow from the first tank to the second tank under gravity.

[0041] The use of gravity to transport aquatic organisms through the flow-through imaging system in FIG. 4 is also provided in the system of FIG. 4 such that the aquatic organisms are removed from the tank and enter the flow-through pipe at a height above the return height of the flow-through pipe. The use of gravity also provides a good solution that takes into consideration the stability and health of the aquatic organisms. The use of gravity provides a simple system in which the aquatic organisms do not need to pass through other equipment, such as a pump. The use of a pump could potentially increase the risk of injury to the aquatic organisms and increase the cost of the system. However, if gravity flow is not possible, it is also possible to provide an embodiment that also includes the use of a pump to allow the aquatic organisms to flow through the flow-through pipe.

[0042] (Example) An example of an imaging system using a flow cell as shown in Figure 6 and used in an experimental setup for acquiring images of larval fish is shown in Figure 5a. Figure 5a can show a schematic of the experimental setup of the imaging system with components using dimensions and locations according to the various data sheets of the components. The trigger system shown is optional. The imaging system in Figure 5a is optimized for larval fish 3-10 mm in length with a maximum diameter of 4 mm. It is also possible to adjust the imaging system to image larval fish 3-30 mm in length, but doing so may reduce the resolution for larval fish 3-10 mm in length.

[0043] In the example shown in Figure 5a, the flow cell has a square cross section, an internal width of 4 mm, and is approximately 300 mm long. The flow cell and mirror are mounted inside a liquid-filled vessel. The mirror used was a 50 x 75 mm reinforced aluminum, 4-6 λ mirror from Edmund Optics. Two illumination sources were mounted outside the vessel. Further details of the flow cell are shown in the enlarged view and are described later with respect to Figure 5b. The camera used was a FLIR Grashopper 3 5MP camera with a TechSpec 0.5x telecentric lens, with a width W of 17.6 mm and a height H of 13.2 mm, giving a total scale of 139 pixels per millimeter. The camera was powered by a 24 V DC power supply. For illumination, two AL295 lamps from MicroBrite® Bar Lights with a total power of 80 W (800 W overdrive) (LED) were used to obtain sufficient illumination even with the lowest possible lens aperture for maximum depth of field, so that the entire volume of the flow cell was in focus. The AL295 lamps used were 89.4 mm long and provided white light (5500 K to 6100 K). The camera was connected to a Raspberry Pi 4, which runs custom software to configure the correct camera settings and capture and store images from the camera. The Raspberry Pi 4 was powered by a 5 V DC power supply. Images were automatically stored on a 128 GB memory stick. The speed of the passing larvae was regulated by a flow valve (not shown). All components were mounted on two pieces of 10 mm HDPE board with supports. A silicone hose was used to connect the funnel to the flow cell.

[0044] Figure 5b shows a detailed view of the flow cell and mirrors, along with a container filled with degassed water from Figure 5a, from the side and front. The flow cell is a square quartz tube with an inner width of 4 mm and a length of approximately 300 mm. Two mirrors were positioned at a 22.5° angle, approximately 11 mm below the flow cell, to achieve two reflections at 90° to each other. The mirrors and flow cell were placed inside a waterproof container filled with degassed water to eliminate optical distortions due to irregularities in the flow cell. The container was made from Lexan. The container could also be filled with, for example, clear mineral oil. The optics and flow cell were optimized for larval fish 3–10 mm long with a maximum diameter of 4 mm.

[0045] Figure 6 shows three images of the same larvae taken using the imaging system previously described and shown in Figures 5a and 5b. The larvae in Figure 6 are newly hatched zebrafish larvae. Approximately 300 newly hatched zebrafish larvae in approximately 1 deciliter of water were flowed through the imaging system. The left and right images were taken with the right and left mirrors and rotated 90° relative to each other. The middle image was taken directly with the zebrafish larvae inside the flow cell. As can be seen from the images, the yolk of the zebrafish larvae has different visibility in the images. Furthermore, in one image, the zebrafish larvae is completely straight, while in another image, the posterior tail is curved. By acquiring images from multiple sides, this increases the opportunity to perform measurements such as morphometric measurements of the zebrafish larvae. The yolk can be measured from one image where the yolk is visible, while the length can be measured from another image. This allows for improved measurement of yolk dimensions as well as other parameters such as length of zebrafish larvae.

[0046] The exemplary imaging system is described for ex-tank imaging of larval fish. The imaging system can also be an in-vivo system. As further described above, the imaging system can also be used to image other small aquatic organisms, such as, for example, small fish, larvae, algae, crustaceans, zooplankton, or eggs from aquatic organisms. The imaging system can be used to observe the size or growth of small aquatic organisms. The imaging system can also be used to construct 3D images of small aquatic organisms, for morphometric measurements of small aquatic organisms, for observing larval growth, for observing larval health, for larval biometry, or for observing larval fish in production tanks.

[0047] Although exemplary embodiments of the present invention have been described, it will be apparent to one skilled in the art that other embodiments incorporating the present concepts may also be used. These and other non-limiting examples set forth above are intended to be illustrative only, with the actual scope of the invention to be determined from the appended claims. [Explanation of symbols]

[0048] 1. Imaging system 2 Tanks 3 Flow Cell 5. Imaging devices 6 illumination source 7 mirror 8 containers 9. Computer 10 Power supply

Claims

1. 1. An imaging system for imaging at least one aquatic organism, comprising: an imaging device; at least two mirrors configured to provide imaging of said at least one aquatic organism from at least two angles; An imaging system comprising:

2. The imaging system of claim 1 further comprising at least two illumination sources.

3. 3. The imaging system of claim 1, wherein the imaging device is positioned on a first side of the at least one aquatic creature, and the at least two mirrors are positioned on a second side of the at least one aquatic creature, the first side being opposite the second side.

4. The imaging system of claim 1 , wherein the at least two mirrors are configured to obtain at least two reflections from the at least one aquatic organism.

5. 5. The imaging system of claim 1, wherein the at least two mirrors and the imaging device are configured to obtain combined images of the at least one aquatic creature from three different angles, a first and second angle being provided by reflection from the at least one aquatic creature onto the imaging device using the at least two mirrors, and a third angle being provided by a direct image of the at least one aquatic creature onto the imaging device.

6. 6. The imaging system of claim 1, wherein each of the at least two mirrors is positioned at a predetermined angle relative to a plane perpendicular to an axis of a field of view of the imaging device, the angle being between approximately 15° and 45°.

7. 7. The imaging system of claim 1, wherein the at least two mirrors are positioned at approximately 22.5° relative to a plane perpendicular to an axis of field of view of the imaging device to obtain two reflections from the aquatic organism at approximately 90° relative to each other.

8. 7. The imaging system of claim 1, wherein each of the at least two mirrors is positioned at an angle of approximately 30 degrees relative to a plane perpendicular to an axis of field of view of the imaging device.

9. The imaging system of claim 1 , wherein at least two illumination sources are positioned on either side of the imaging device.

10. 10. The imaging system of claim 1, wherein the at least two mirrors are configured to acquire a combined image of the at least one aquatic organism provided by views from three different angles, the three different views being at angles of 120° relative to each other, two of the angles being reflections from the aquatic organism to the imaging device via the at least two mirrors, and a third angle being a direct image of the aquatic organism to the imaging device.

11. 11. The imaging system of claim 1, wherein the at least two mirrors are arranged symmetrically or nearly symmetrically with respect to an axis of field of view of the imaging device.

12. 12. The imaging system of claim 1, wherein the at least two mirrors are positioned to allow the same focal region for the imaging device for a viewing angle.

13. The imaging system of claim 1 , wherein the imaging device comprises a telecentric lens.

14. The imaging system of claim 1 , wherein the at least one aquatic organism is configured to flow through a flow cell while being imaged by the imaging device.

15. 15. The imaging system of claim 14, wherein the flow cell and the at least two mirrors are disposed inside a container filled with a transparent material, preferably a degassed liquid or a transparent resin.

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

17. The imaging system of claim 14 , wherein the flow cell is transparent.

18. The imaging system of claim 15 , wherein the container is transparent.

19. 19. The imaging system of claim 1, wherein the container is made from polycarbonate or quartz.

20. 20. The imaging system of claim 1, wherein the flow cell is made from polycarbonate, quartz, or plastic.

21. 21. The imaging system of claim 14, wherein the flow cell comprises at least one optical diffuser.

22. 22. The imaging system of claim 1, wherein the images of the at least two angles / sides of the at least one aquatic organism are acquired simultaneously.

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

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

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

26. 23. Use of an imaging system according to any one of claims 1 to 22 for observing the size or growth of small aquatic organisms.

27. 26. Use of an imaging system according to any one of claims 1 to 22 or a flow-through imaging system according to any one of claims 23 to 25 for constructing 3D images of small aquatic organisms.

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

29. 26. Use of the flow-through imaging system of any one of claims 23 to 25 for monitoring the growth of larvae, or for monitoring the health of larvae, or for biology of larvae, or for monitoring larvae in production tanks.

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

Images