Abstract: Aiming at the problem that the traditional method of image extraction of human motion could only obtain the local optimal solution, and the extracted feature sequence was discontinuous, which led to the poor contour extraction effect, we proposed an image attitude contour extraction algorithm of nonrigid human motion. First, the scaleinvariant feature transform (SIFT) in the human motion image sequence was extracted and preprocessed to obtain the human feature 
extraction graph, and a sequential probability graph model of the human motion sequence was designed to ensure the continuity of the feature sequence extraction. Then the exterior appearance model of human limbs was constructed. 
Based on the appearance model, the high precision contour extraction algorithm of sequential image was used to extract the contour line of the current human motion frame. The experimental results show that the proposed algorithm can extract
 continuous feature sequences, and the extracted human pose contours have high accuracy, high efficiency and robustness.

Key words: nonrigid human motion, motion image, correct, attitude contour, extraction algorithm