Key Frames Extraction Based on Optical-flow and Mutual Information Entropy

Abstract

Key frames provide a suitable video summary and framework for video indexing, browsing and retrieval, and how to extract key frames is the core in the field of video retrieval. In order to solve the problem of redundancy and missing selection in key frame extraction, this paper proposed a key frame extraction algorithm based on optical flow and mutual information entropy. This algorithm integrates mutual information entropy and optical flow characteristics to extract key frames. First, the optical flow method calculated the total optical flow of each frame of the image, and selected the video frame with extreme optical flow difference in the neighbourhood as the key frame, and the other video frames were put into the candidate key frame set; by calculating the mutual information entropy of the key frame set, the minimum mutual information entropy is taken as the threshold; Then, The mutual information entropy of the candidate key frame set was calculated, and the image frames larger than the threshold value were put into the key frame set; Finally, redundant key frames are deleted through the measurement of inter-frame similarity, and the remaining key frames are the key frames to be extracted. The experimental results show that compared with other methods, the accuracy of extracted key frames by this approach is significantly improved on precision, recall and F-score, and the extracted key frames can reflect video content more effectively.