Study On The Composition Of Spawning Grounds For Gravel Fish In The Upper Reaches Of The Yangtze River Based On Image Recognition

There are various types of landforms in the upper reaches of the Yangtze River,with large elevation differences in the riverbed,complex habitats,and abundant water resources,which breed a large number of rare and unique fish species.However,due to intensified human activities,the habitats of many sticky egg producing fish in the upper reaches of the Yangtze River have been damaged to varying degrees.As the river sediment is an important physical part of the river biological habitat,it forms the physical environment for the development of zygote and early embryos of cohesive fishes,which may directly affect the scale and effect of natural reproduction of bottom cohesive spawning fishes.Therefore,the study of the composition of the substrate in spawning grounds is of great significance for the protection and repair of spawning grounds.This research topic focuses on the spawning ground from Yibin to Jiangjin in the upper reaches of the Yangtze River,and optimizes the automatic measurement method of plasmid diameter distribution in the riverbed of the spawning ground based on image processing.To address the issue of over segmentation,a method for optimizing over segmentation using labeled foreground objects as protective covers is proposed;To solve the problem of under segmentation,the pebble ellipse plus hypothesis is proposed,and the shape coefficient is used to classify the pebbles in the binary image,and then the pebbles are divided twice according to different types,so as to solve the problem of under segmentation and greatly improve the measurement accuracy;And an investigation was conducted on 17 spawning grounds in the upper reaches of the Yangtze River,analyzing the particle size distribution characteristics of riverbed sediment pebbles in the spawning grounds,and proposing the main measures for repairing the composition of sediment in the spawning grounds.The main research results are as follows:(1)Construct a method based on image processing to automatically measure the distribution of plasmid diameter at the riverbed of spawning grounds,and improve traditional image processing methods.Propose an over segmentation optimization method using labeled foreground objects as protective covers,which automatically removes the watershed algorithm segmentation lines inside the protective covers and solves the problem of over segmentation.A shape coefficient classification method for pebble images is proposed based on the assumption of pebble ellipses,which solves the problem of undersegmentation by segmenting and supplementing different types of pebbles separately.The processing effect of the above optimization methods is closer to the true value of the particle size distribution measured by traditional image processing methods.The relative error of the measurement is reduced from 60% to 12%.In the suitability analysis of this method,the deviation is reduced from 0.53 to 0.07,and the irreducible random error is reduced from 0.28 to 0.04.(2)A survey was conducted on 17 typical spawning grounds for sticky fish in the upper reaches of the Yangtze River.The measurement results of pebble particle size in the spawning grounds showed that most of the riverbed bottom plasmid sizes ranged from 2 to 45.6cm,with a median particle size(D50)range of 4.43 to 8.21 cm,and a mean D50 of 6.24.Pebbles below 10 cm account for 64.8%-91.9% of the total pebbles,with an average of 77.71%;The proportion of pebbles between 2-6cm in most spawning grounds ranges from 40% to 55%,with an average of 48.15%.The comprehensive analysis of 17 spawning grounds shows that the particle size distribution of most spawning grounds is similar.Except for the spawning grounds of Jinyuhao and Hongdengqi,the correlation coefficients of the other 15 spawning grounds are between0.610 and 0.996;The 17 spawning grounds mainly exhibit differences in particle size distribution on small pebbles ranging from 2-8cm,while the differences in large pebbles are relatively small.The research results of the paper can alleviate the work of measuring the distribution of plasmid diameter in the riverbed of spawning grounds,and provide data support for the protection of spawning grounds for sticky fish in the upper reaches of the Yangtze River.