Abstract:Two dimensional Fourier transform(FFT) was adopted to remove groove, and a homomorphic filter algorithm was employed to enhance the crack contrast in frequency domain. An adaptive direction LoG algorithm was employed to highlight the crack. The Otsu method was resorted to processing the global image into binary images and the grid method was adopted to extract crack fragment. Finally, the degree of target smooth was calculated with the curve cumulative turning method, and the removal of the “asphalt drawing” was realized. Experiments prove this method to be of good recognition effect.