An efficient motion field representation using JBIG approach for video compression

In this study, a simple and efficient scheme to improve the compression ratio of the block-based motion fields in the video compressing is proposed. In the proposed scheme, each motion field is represented by a small set of coded motion vectors and a binary bitmap. Some of the motion vectors in a motion field, named as significant motion vectors (SMVs), have the property of being significantly different from the motion vectors of their spatial or temporal adjacent blocks. Instead of coding all the motion vectors in a motion field, only the SMVs need to be coded in the proposed scheme. For each block in a frame, one bit, corresponding to its position on the binary bitmap, is used to record if the motion vector is significant or not. And then, the joint bilevel image experts group (JBIG) image coding standard is applied on the bitmap to improve the bit-rate. The experimental results reveal that more than half of the motion vectors are non-significant and can be omitted on coding procedure. Although there exists an overhead of JBIG coded binary bitmap, the coding improvement ratio of the proposed scheme is over 40% on average when comparing with the conventional variable length coding (VLC) scheme.