An efficient foreground-based surveillance video coding scheme in low bit-rate compression

Many works have been done in the area of surveillance video compression, while problems still exist. The block-based schemes have blocking artifacts in the edge of foreground, while the object-based coding schemes have excessive bit consumption for coding the object shape. A novel foreground-based (FG-based) coding scheme is presented in this paper to solve these two problems and can gain better video quality at low bit-rate. The improvement comes from: 1) obtaining a foreground frame (FG-frame) by segmentation, in which proper constant value 128 is adopted to represent the luminance and chrominance value of background pixel and thus the residue error is reduced; 2) FG-based motion estimation (ME) and motion compensation (MC), which are more accurate for the foreground prediction and reduce the residue error of edge block in the foreground; 3) a new coding mode (BG-mode) is designed to better code the background when it is falsely segmented as foreground in FG-frames; 4) FG-based rate distortion optimized (RDO) mode decision (MD) is proposed to emphasize the foreground by calculating the distortion in the foreground domain; 5) avoiding shape coding by recovering the shape mask from the reconstructed foreground (REC-FG) frame and the constant background value 128. Our scheme is implemented with AVS encoder platform and the experiment results show the efficiency of the proposed scheme.