Scalable Coding Research On Video Image In Wavelet Domain

With the development of business progress,Internet popularization and proceeding of digital signal technology, the scalable coding technology of video image based on wavelet transform is becoming the hotspot of video compression research. In the modern coding system, people just use traditional methods to code the intra frame image and motion compensation prediction error information (we call it MCPR for short afterwards) image, like JPEG compression algorithm. In fact, video frame, especially the MCPR image has different characteristic to natural image. If we use these normal methods to code video frame, the compression efficiency will be decrease. Therefore, the improvement of video coding is depended on how to reduce the use of intra frame image and MCPR image. So, it is very important to video compression.The research of this paper is main part of project which is supported by nation natural funds-fine granularity scalable coding research of video based on object (No:60372071). The paper first compares the statistical property of intra frame image to MCPR image, and then concentrates resources to method of video compression. In the field of intra frame image coding, the paper has put forward a scalable quantization method of wavelet subband statistical characteristics. Based on this method, the paper proposed a PSNR scalable image coding scheme which use the significance of coefficient and bit-plane technique. The scheme constructs different bit-planes according to the target bit rates so as to achieve PSNR scalability. The experimental results prove that the proposed method can be implemented simply and achieve high code / decode speed and good compression quality. On the premise of high coding quality, the method can realize image's PSNR scalable coding. Moreover, the decode image can get a better quality at very low bit rate. With the growth of decoding bit rate, the number of bit-plane increases and the quality of decoding image improves. The proposed scheme can satisfy the progressive transmission of intra frame image. In the field of MCPR image coding, a double-stage quantization method is proposed in the paper combining with the statistical property of MPCR image. Then a PSNR scalable coding scheme of MCPR image based on bit-plane technique is proposed. The scheme considers the importance of each subband, and uses different coefficients to quantize the high frequency which has lots of information. These two steps confirm the decoding quality of MCPR image. The scheme constructs different bit-planes according to the target bit rates so as to achieve PSNR scalability. Simulation results prove that the compression quality of our method is superior to SPITH algorithm, especially at the very low bit rates. The proposed method can satisfy the progressive transmission of MCPR image.