Automatic counting system for fish passing amount of fish passage based on underwater videos

Abstract

The invention relates to an automatic counting system for the fish passing amount of a fish passage based on underwater videos. The system comprises an underwater camera and a video processing work station, and the underwater camera is connected with an image collection card of the video processing work station. The inlet of the fish passage is provided with an escape preventive net, the underwater camera is mounted in the sidewall of the fish passage and close to the outlet of the escape preventive net, and a light source is mounted over a shooting scene to light and illuminate underwater part in the fish passage. In the video processing process, part area in a visual field is designed as a counting buffer area via software to reduce the computational complexity, and further, an enhanced counting area is arranged in the countering buffer area. when fishes enter an effective counting area gradually from one side, the system identifies and tracks the fished automatically continuously, when the system finds, by tracking, that certain fish enters the enhanced counting area from onside and exits out of the other side gradually, counting is to be carried out, counting is started after monitoring and confirming in three continuous frames of images, and thus, the practical fish passing amount in the fish passage can be counted automatically all-day in a counting period.

Description

technical field [0001] The invention relates to the field of underwater target monitoring and counting, in particular to an automatic counting system for the amount of fish passing through a fishway based on underwater video. Background technique [0002] In recent years, a large number of various types of hydropower stations have been built in my country. The dams of these stations have caused difficulties for the free migration of fish, especially seasonal and physiological migration, threatening the survival and reproduction of fish. In order to solve this problem, the newly-built dam is specially designed with a fishway for fish to pass through, and uses light, sound and biochemical fish luring technology to try to induce fish to the entrance of the fishway, guide and help them pass through the fishway. However, different fish have different abilities to pass through the fishway, and different types of fishways also make the fish pass through the dam differently. Therefo...

AI Technical Summary

Problems solved by technology

However, due to the randomness of the time and quantity of fish passing, it is impossible to monitor the fishway manually 24 hours a day, and it is necessary to develop automated and intelligent monitoring and statistical methods

Studies have shown that general magnetic, electric and contact sensors are not suitable for fish counting work, and vision technology has the advantages of non-contact, visualization, and easy signal collection and transmission, which can be applied to the development of fish counting in fishways, but still There are many technical difficulties, which are mainly manifested in: (1) low visibility in natural water environment, strong light scattering and reflection, which makes video contrast poor and makes it difficult for fish target recognition; (2) fish is a flexible body, swimming During the process, the posture is changeable, and there are no obvious distinguishing features between the same fish except the size, which makes it difficult for the fish to lock and track; (3) Fish generally have phototaxis or flow, and the light source and fishway in the field of view Under the current of water, fish tend to hover in the field of view of the camera, shake their fins (causing body changes), roll over, swim back, etc., all of which make it difficult to count

[0003] The published invention patent ("An automatic counting system for live fish based on computer vision", 201510437308.7) proposes a video counting method that can be used for fry counting, but due to the limitations of experimental facilities, conditions, methods, etc., it cannot be used in It is used in the natural water environment, especially in real dam fishways, mainly because of: (1) hardware: the size of the fishway is only tens of centimeters, so the detected fish must be small enough and have a small range of activities. The state is single, and additional water filter tanks, fish suckers, fish dividers, etc. are required. These limiting conditions are impossible to realize in the real dam fishway monitoring environment; (2) counting rules and methods: in this invention, select the For an experimental fishway with a downward slope in the downstream direction, it is considered that when a tracked fish is detected when the center of mass coordinates of the current frame is lower than that of the previous frame, the counter is incremented by 1, but in fact, it is extremely rare for a fish to swim in the fishway. Regularly, common fish swim up and down quickly along the water depth direction in a small area, or hang somewhere and shake their tails, causing the position of the center of mass to change (in fact, there is no obvious shift), especially when there is a light source. Because of the phototaxis, the group tends to swim around the light source in a "vortex" shape. These common situations will invalidate the counting rules of the patent

In addition, the "standard background" used in this patent is to first shoot and extract the scene without fish as the standard background template, and then use the difference between the current frame image and the standard background template to obtain the foreground (fish) during monitoring. It is also unavailable in the dam fishway, because the water quality, flow velocity, and natural environment light in the dam fishway will change, resulting in different visibility, that is, the background will change, and it is not suitable to use a fixed background template

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