Traditionally, the defect detection of solid-rocket engine in China is manipulated by technical personnel by means of X-ray crack-detection film. The automatic level for this manner is lower and also often makes mistakes caused by technical personnel's subjective factors. This paper tries to change this situation by doing the following research works:1. Make use of edge detection technique based on wavelet transform to find out the edges in the image and detect some no-clear defects derived from X-ray crack...