The invention relates to a method for characterizing the size of an irregular proppant-
fiber cluster unit in a slit, and the method comprises the steps: S1, carrying out a proppant-
fiber mixed conveying
physical model experiment, obtaining an experiment image, carrying out the preprocessing and threshold segmentation of the experiment image, focusing on a
region of interest (ROI), and obtaining a proppant-
fiber cluster
unit size; dividing the pixel value of the image into continuous intervals according to a preset threshold parameter, and generating a multi-category segmentation
mask; s2, performing multi-scale morphological operation on the segmented masks, removing small
noise cluster units and filling internal holes of the cluster units; s3, identifying each connected region in the image, counting the area of the connected region, and dividing cluster units according to a preset level; and S4, performing
color gradient rendering, contour labeling and area numerical value labeling on the cluster units of different levels to enhance the
visual discrimination, and outputting an image. According to the experimental
image processing method provided by the invention, the information of each cluster unit can be more intuitively obtained, and the action mechanism of the proppant-fiber cluster unit can be clearly known.