Abstract: Due to water erosion, natural aging and other problems, underwater structures such as reservoirs have surface damage defects during long-term operation. The depressions formed by attachments such as moss and shells on the surface of underwater structures are highly similar to cracks in terms of color and texture. When the depressions are close to cracks, it is easy to cause misjudgment in crack image segmentation. In order to solve this problem, the polarization information is introduced in this paper, and a crack image segmentation algorithm based on polarization degree feature map is proposed. The feature map is extracted by superpixel block, the region growth rule is set by polarization degree, and the region growth is combined based on seed region. Finally, the crack region is determined according to the image depth map. The experimental results show that this algorithm can effectively reduce the segmentation misjudgment, and the specificity and accuracy index of crack segmentation results can reach more than 0.9, which is much higher than other algorithms.

Key words: polarized image, SLIC algorithm, region growth, crack segmentation