Image segmentation and motion-adaptive frame interpolation for coding moving sequences

The authors describe an approach to the coding of moving sequences that combines image segmentation with adaptive thresholding based on a priori knowledge about the scene and motion-adaptive frame interpolation techniques. In videoconference pictures the face is an area of high movement, and it is also the most noticeable part of the picture. Using such knowledge about the scene, the location of the face in alternate frames is determined, and a set of thresholds is chosen that allows segmentation of this part of the image more accurately than of the background. To achieve the high compression ratios required for transmission of videoconference and videophone pictures over the existing networks, only alternate frames are coded and transmitted. At the receiver a skipped frame k is produced by motion-adaptive interpolation of corresponding blocks of frames k - 1 and k + 1.