An underwater fish sound shadow integrated observation system based on a polarization camera and a working method thereof

Abstract

The application discloses an underwater fish sound shadow integrated observation system based on a polarization camera, which comprises an underwater detection terminal, wherein the underwater detection terminal comprises a pressure-resistant cabin body, a polarization imaging module, a synchronous control module, a detection module and a data fusion processing module which are integrated in the pressure-resistant cabin body; the polarization imaging module acquires multi-polarization direction images and videos of underwater targets, and the detection module acquires acoustic information of the underwater targets; the synchronous control module performs space-time synchronization on information of the polarization imaging module and the detection module; and the data fusion processing module receives the space-time synchronized data information and generates comprehensive observation results. Compared with the prior art, the underwater fish sound shadow integrated observation system based on the polarization camera and the working method thereof have the advantages that high-precision space-time synchronization and a self-adaptive fusion algorithm are used to realize underwater fish sound shadow monitoring.

Description

Technical Field

[0001] This invention relates to the field of underwater detection technology, specifically to an integrated underwater fish acoustic and visual observation system based on a polarization camera and its working method. Background Technology

[0002] Monitoring underwater biological resources is of great significance for marine ecological protection, fisheries resource assessment, and underwater environmental research. Currently, underwater fish observation mainly relies on single optical imaging or acoustic detection technologies.

[0003] Traditional optical cameras are highly susceptible to scattering from suspended particles, light attenuation, and backscattering in underwater environments, especially in turbid waters or low-light conditions. This results in low image contrast, blurred details, and difficulty in accurately identifying the morphological characteristics and species of fish. Although polarization imaging technology can improve image clarity by filtering out scattered light, it still has limitations in completely dark or extremely turbid environments.

[0004] On the other hand, although sonar detection technology has strong penetrating power and is not affected by light, and can obtain the distance and general outline of the target, its resolution is relatively low, making it difficult to provide details of the texture, color information and specific biological behavior characteristics of the fish surface, and it is also subject to serious noise interference, making species identification difficult.

[0005] Existing observation systems often simply piece together optical and acoustic equipment, lacking in-depth spatiotemporal synchronization mechanisms and multi-source data fusion algorithms. This results in the inability to accurately match photoacoustic data in time and space, making it difficult to form complementary advantages and achieve all-weather, high-precision comprehensive fish observation in complex and ever-changing underwater environments. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the above-mentioned technical defects and provide an integrated underwater fish acoustic and shadow observation system based on a polarization camera and its working method, which realizes underwater fish acoustic and shadow monitoring through a high-precision spatiotemporal synchronization and adaptive fusion algorithm.

[0007] To solve the above-mentioned technical problems, the technical solution provided by the present invention is: an underwater fish acoustic and shadow integrated observation system based on a polarization camera, including an underwater detection terminal, wherein the underwater detection terminal includes a pressure-resistant chamber, and a polarization imaging module, a synchronization control module, a detection module, and a data fusion processing module are integrated in the pressure-resistant chamber;

[0008] The polarization imaging module acquires multi-polarization images and videos of underwater targets, and the detection module acquires acoustic information of underwater targets.

[0009] The synchronization control module performs spatiotemporal synchronization of information from the polarization imaging module and the detection module. The data fusion processing module receives the spatiotemporally synchronized data information and generates comprehensive observation results.

[0010] Preferably, the comprehensive observation results include fish morphology, location, movement trajectory, and polarization characteristics.

[0011] Preferably, the polarization imaging module includes an adjustable polarization filter to acquire sub-images in four polarization directions: 0°, 45°, 90°, and 135° in a single exposure.

[0012] Preferably, the detection module emits acoustic pulses and receives echo signals reflected from the target, generating an acoustic intensity image or three-dimensional point cloud data of the underwater target.

[0013] Preferably, the synchronization control module includes a time synchronization unit, a spatial positioning unit, and a trigger signal generator;

[0014] The time synchronization unit completes the time synchronization between the polarization imaging module and the detection module based on the PTP precision clock protocol.

[0015] The spatial positioning unit locates the spatial position of the underwater detection terminal, and the trigger signal generator synchronously triggers the detection module to emit acoustic pulses when the polarization imaging module acquires images.

[0016] Preferably, the data fusion processing module includes an image preprocessing unit, an acoustic data decoding unit, and a feature fusion unit;

[0017] The image preprocessing unit performs noise reduction, distortion correction, and polarization parameter calculation on the polarized image.

[0018] The acoustic data decoding unit extracts the target's distance, orientation, size, and speed.

[0019] The feature fusion unit integrates polarization features and acoustic features to output fish species, behavioral status, and environmental parameters.

[0020] Another aspect of this invention discloses a working method for an underwater fish acoustic-visual integrated observation system based on a polarization camera, comprising the following steps:

[0021] S1: Start the polarization imaging module to acquire images and videos in multiple polarization directions, and simultaneously trigger the detection module to emit sound waves and receive echoes to collect acoustic information;

[0022] S2: Denoise, correct distortion, and calculate polarization parameters for polarization images; decode acoustic information to generate acoustic intensity images or 3D point clouds.

[0023] S3: Based on the spatiotemporal stamp provided by the synchronization control module, align the preprocessed polarization image with the acoustic data in the coordinate system.

[0024] S4: Integrates polarization and acoustic features to identify and output the species, morphology, location, movement trajectory, and polarization features of fish.

[0025] S5: Transmit the comprehensive observation results to the surface control station or local storage.

[0026] Preferably, step S4 includes real-time evaluation of the turbidity or signal-to-noise ratio of the current water body based on an adaptive weighting strategy;

[0027] When the turbidity of the water body is higher than the preset threshold, the acoustic features are given a higher fusion weight, and the target location is determined mainly by the acoustic profile.

[0028] When the turbidity of the water is lower than the preset threshold, the optical polarization features are given a higher fusion weight, and the details of the polarization texture are used to help determine the species and surface condition of fish.

[0029] The advantages of this invention compared to the prior art are:

[0030] In this invention, by integrating a polarization imaging module, underwater backscattered light is effectively filtered out, significantly improving the image clarity and contrast in turbid waters, and enabling the capture of fish surface textures and polarization features that cannot be identified by ordinary cameras.

[0031] In this invention, the detection module and the polarization imaging module work together to make up for the shortcomings of optical detection at long distances or in the absence of light by utilizing the strong penetrating power of sound waves, thus achieving the complementary advantages of "acoustic ranging and positioning, and optical qualitative and species identification".

[0032] Furthermore, the microsecond-level spatiotemporal synchronization achieved through the synchronization control module ensures accurate registration of photoacoustic data at the pixel and point cloud levels. Combined with the adaptive weighting strategy of the data fusion processing module, the system can automatically adjust the fusion strategy according to the aquatic environment, maintaining highly reliable observation results in both turbid and clear waters, and significantly improving the intelligence level and environmental adaptability of underwater fish observation. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of an underwater fish acoustic and visual integrated observation system based on a polarization camera. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings.

[0035] Combined with appendix Figure 1As shown, an underwater fish acoustic-visual integrated observation system based on a polarization camera is presented. The core component is an underwater detection terminal, which is externally encased in a high-strength pressure-resistant cabin. Internally, it highly integrates a polarization imaging module, a synchronization control module, a detection module, and a data fusion processing module. The integrated design reduces the equipment size and installation complexity, making it particularly suitable for mounting on AUVs or ROVs.

[0036] In one embodiment, the core component of the polarization imaging module is an adjustable polarization filter. This filter can employ a liquid crystal variable retarder or a mechanical rotating wheel structure, enabling rapid switching or beam splitting to acquire sub-images in four polarization directions: 0°, 45°, 90°, and 135° within a single exposure cycle. By acquiring images, the system can calculate the degree of polarization (DoP) and angle of polarization (AoP) of the scene in real time, effectively removing water scattering noise and restoring the true surface texture of fish.

[0037] In one embodiment, the detection module employs a high-frequency sonar transducer to emit narrow-beam acoustic pulses and receive echo signals reflected from the target. This module can not only generate two-dimensional acoustic intensity images, but also generate three-dimensional point cloud data of underwater targets through multi-beam or synthetic aperture technology, accurately providing information on the distribution density, individual size, and spatial location of fish schools.

[0038] The synchronization control module ensures the accuracy of data fusion. Its internal time synchronization unit is based on a precision clock protocol to synchronize the system clocks of the polarization imaging module and the detection module to the microsecond level of error.

[0039] The spatial positioning unit, combined with the inertial navigation system (INS) and Doppler velocimeter (DVL), calculates the terminal's six degrees of freedom attitude and position in real time. The trigger signal generator emits a hardware trigger signal at the start of the polarization camera's exposure to drive the sonar transmission pulse, ensuring that each frame of optical image has corresponding acoustic echo data, achieving audio-visual synchronization.

[0040] In one embodiment, the data fusion processing module runs a high-efficiency fusion algorithm. The image preprocessing unit first performs dark current removal and lens distortion correction on the original polarization image and calculates the polarization feature map. The acoustic data decoding unit performs beamforming and envelope detection on the echo signal to extract the target's range, azimuth, radial velocity, and reflection intensity. Subsequently, the feature fusion unit uses the spatiotemporal extrinsic parameter matrix provided by the synchronization control module to register the optical pixel coordinates with the acoustic point cloud coordinates.

[0041] In terms of specific fusion strategies, the system adopts an adaptive weighting mechanism. When the sensor detects high turbidity in the water (such as in estuaries after heavy rain) or low signal-to-noise ratio, the algorithm automatically reduces the weight of optical data, relying mainly on acoustic contours to determine the location and quantity of fish, thus avoiding interference from false images. Conversely, in clear waters, the system assigns higher weight to optical polarization features, utilizing the unique polarization reflection characteristics of fish scales to assist in determining fish species, size, and even health status, outputting comprehensive observation results that include species, morphology, location, trajectory, and polarization features.

[0042] In specific implementation of the present invention,

[0043] The first step is to start the system. The polarization imaging module continuously acquires multi-angle polarization video, while simultaneously triggering the detection module to emit sound waves and receive echoes, completing the dual-mode acquisition of raw data.

[0044] The second step is to perform data preprocessing. The optical end completes denoising and polarization parameter inversion, while the acoustic end completes beamforming and feature decoding to generate standardized acoustic intensity maps or point clouds.

[0045] The third step involves using high-precision spatiotemporal stamps and calibrated extrinsic matrix to project optical images and acoustic data onto the same world coordinate system, thus achieving pixel-level and point-level alignment.

[0046] The fourth step is to perform feature fusion and target recognition. The sound and light fusion weights are dynamically adjusted based on the real-time assessment of water turbidity to identify fish species and analyze their behavioral patterns (such as schooling, foraging, and escaping).

[0047] The fifth step is to transmit the final comprehensive observation results to the surface control station via an underwater acoustic communication device, or store them on a local solid-state drive for subsequent analysis.

[0048] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0049] The working principle of this invention is as follows:

[0050] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0051] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. An underwater fish acoustic-visual integrated observation system based on a polarization camera, characterized in that: It includes an underwater detection terminal, which includes a pressure-resistant chamber and integrates a polarization imaging module, a synchronization control module, a detection module, and a data fusion processing module within the pressure-resistant chamber. The polarization imaging module acquires multi-polarization images and videos of underwater targets, and the detection module acquires acoustic information of underwater targets. The synchronization control module performs spatiotemporal synchronization of information from the polarization imaging module and the detection module. The data fusion processing module receives the spatiotemporally synchronized data information and generates comprehensive observation results.

2. The underwater fish acoustic-visual integrated observation system based on a polarization camera according to claim 1, characterized in that: The comprehensive observation results include fish morphology, location, movement trajectory, and polarization characteristics.

3. The underwater fish acoustic-visual integrated observation system based on a polarization camera according to claim 1, characterized in that: The polarization imaging module includes an adjustable polarization filter, which acquires sub-images in four polarization directions—0°, 45°, 90°, and 135°—in a single exposure.

4. The underwater fish acoustic-visual integrated observation system based on a polarization camera according to claim 3, characterized in that: The detection module emits acoustic pulses and receives the echo signals reflected by the target, generating an acoustic intensity image or three-dimensional point cloud data of the underwater target.

5. The underwater fish acoustic-visual integrated observation system based on a polarization camera according to claim 4, characterized in that: The synchronization control module includes a time synchronization unit, a spatial positioning unit, and a trigger signal generator; The time synchronization unit completes the time synchronization between the polarization imaging module and the detection module based on the PTP precision clock protocol. The spatial positioning unit locates the spatial position of the underwater detection terminal, and the trigger signal generator synchronously triggers the detection module to emit acoustic pulses when the polarization imaging module acquires images.

6. The underwater fish acoustic-visual integrated observation system based on a polarization camera according to claim 2, characterized in that: The data fusion processing module includes an image preprocessing unit, an acoustic data decoding unit, and a feature fusion unit; The image preprocessing unit performs noise reduction, distortion correction, and polarization parameter calculation on the polarized image. The acoustic data decoding unit extracts the target's distance, orientation, size, and speed. The feature fusion unit fuses polarization features and acoustic features. Output fish species, behavioral status, and environmental parameters.

7. The working method of an underwater fish acoustic-visual integrated observation system based on a polarization camera according to any one of claims 1 to 6, characterized in that: Includes the following steps: S1: Start the polarization imaging module to acquire images and videos in multiple polarization directions, and simultaneously trigger the detection module to emit sound waves and receive echoes to collect acoustic information; S2: Denoise, correct distortion, and calculate polarization parameters for polarization images; decode acoustic information to generate acoustic intensity images or 3D point clouds. S3: Based on the spatiotemporal stamp provided by the synchronization control module, align the preprocessed polarization image with the acoustic data in the coordinate system. S4: Integrating polarization and acoustic features Identify and output the species, morphology, location, movement trajectory, and polarization characteristics of fish. S5: Transmit the comprehensive observation results to the surface control station or local storage.

8. The working method of an underwater fish acoustic-visual integrated observation system based on a polarization camera according to claim 7, characterized in that: S4 includes real-time evaluation of the turbidity or signal-to-noise ratio of the current water body based on an adaptive weighting strategy; When the turbidity of the water body is higher than the preset threshold, the acoustic features are given a higher fusion weight, and the target location is determined mainly by the acoustic profile. When the turbidity of the water is lower than the preset threshold, the optical polarization features are given a higher fusion weight, and the details of the polarization texture are used to help determine the species and surface condition of fish.

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