State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research and Hydropower Research;
School of Naval Architecture,Ocean and Civil Engineering;
China Institute of Water Resources and Hydropower Research;
No.125 Geology Brigade,Hubei Bureau of Coal Geology;
borehole image; crack recognition; image processing; segmentation; Hough transform; HSV color model;