System and method for measuring particle size distribution of sediment grains

A system for measuring particle size distribution of sediment grains, comprising:

• an image acquisition module comprising a first camera and a second camera, wherein the first camera is configured to acquire an image of sediment grains in a water body to obtain a first sediment grain image, and transmit the first sediment grain image to an image preprocessing module, and the second camera is configured to acquire an image of the sediment grains in the water body to obtain a second sediment grain image, and transmit the second sediment grain image to the image preprocessing module;
• the image preprocessing module, configured to obtain a sediment grayscale image by performing grayscale processing and median filter processing on the first sediment grain image, and transmit the sediment grayscale image to a grain identification module, and further configured to obtain a depth image based on the first sediment grain image and the second sediment grain image, then obtain a depth grayscale image by performing grayscale processing and median filter processing on the depth image, and transmit the depth grayscale image to the grain identification module;
• the grain identification module, configured to output a preliminary region mask for sediment grains based on the depth grayscale image and a preset depth value range, crop the sediment grayscale image using the preliminary region mask, identify the sediment grains and obtain an image with first-stage clustering results by performing cluster analysis on the cropped sediment grayscale image using a K-means clustering algorithm, obtain an image with second-stage clustering results by performing cluster analysis on the sediment grains with a particle size smaller than a preset threshold in the image with first-stage clustering results using a DBSCAN clustering algorithm, and transmit the image with second-stage clustering results to an edge detection module;
• the edge detection module, configured to obtain a grain edge contour map by performing edge detection on the sediment grains in the image with second-stage clustering results, and transmit the grain edge contour map to an image binarization module;
• the image binarization module, configured to obtain a binarized image by performing binarization processing on the grain edge contour map, and transmit the binarized image to an equivalent transformation module;
• and
• the equivalent transformation module, configured to obtain the particle sizes of the sediment grains by performing an equivalent circular diameter transformation on the binarized image, and obtain a particle size distribution result by statistically analyzing the particle size distribution of the sediment grains.