Abstract: In a single color stone slab,crack is one of the main linear defects.Conducts the research in digital image processing in the category of stone slab crack recognition algorithm.According to the characteristics of fracture image,first of all is to do the image preprocessing,in order to ensure the accuracy of recognition.Mainly study is image correction and enhancement,in order to eliminate noise and to protect bounding around the largest degree.Then image of linear fracture filtering was segmented by using the improved threshold segmentation algorithm;Mathematical morphology was used to single pixel refinement of crack,and to gain crack size.

Key words: linear fracture filtering, recognition algorithm, crack detection