A novel algorithm for detecting and tracking extended target using the projection curves analysis and correlation tracking based on the maximum matching pel count (MPC) criterion is presented. First, the projection curves of the difference image of two consecutive frames are analyzed to find the approximate areas of moving target on the entire scenes. Then correlation tracking based on the improved MPC criterion is used for target tracking against the cluttered background. Experimental results show, as compared to the conventional approaches, the proposed algorithm is more robust, has higher precision, and has simplified computational complexity for tracking an extended target against a cluttered background. (c) 2007 Society of Photo-Optical Instrumentation Engineers.