This document discusses different feature extraction algorithms that can be used in visual sensor networks (WVSN). It begins by explaining the traditional "compress-then-analyze" approach and introduces the newer "analyze-then-compress" approach. The document then reviews several real-valued and binary feature extraction algorithms such as SIFT, SURF, BRIEF, BRISK, and BinBoost. It proposes a video coding system that uses the BRISK algorithm to extract features, encodes the features using entropy coding, and transmits the data to a base station for matching with stored image data. Diagrams of the proposed system and the BRISK algorithm are also included.