In the pretreatment work before the image analysis and identification of rock blocks,in order to smooth the local noise of the rock image and protect the target area in the rock image,the binarization segmentation is conducted on the rock image.ImagePy is used as the image preprocessing analysis method of opencast explosion bonded rock fragmentations,and the main points of image collection in open blasting pile and the way to consider the regional variation coefficient of small rock masses are defined.The bilateral filter plug-in based on ImagePy is developed.Three parameters(30,11,11) is sele...