This book constitutes the refereed proceedings of the 4th International Conference on Image and Signal Processing, ICISP 2010, held in Qu?bec, Canada June 30 - July 2, 2010. The 69 revised full papers were carefully selected from 165 submissions. The papers presented are organized in topical sections on Image Filtering and Coding, Pattern Recognition, Biometry, Signal Processing, Video Coding and Processing, Watermarking and Document Processing, Computer Vision and Biomedical Applications.