Application Research Of SA-APBT In Object-based Color Image And MPEG-4 Video Coding

In applications like remote sensing image coding, telemedicine and remote monitoring, observers tend to focus on some objects in the image or video, whereas are not interested in other objects. Under this circumstance the object-based approach is considered as a very promising alternative to the block-based approach. The traditional object-based coding approach which uses Shape-Adaptive Discrete Cosine Transform (SA-DCT) in the coding of texture, is widely applied because of low complexity and effective coefficients decorrelation. The disadvantage of it is the serious blocking effects at low bit rates. In order to solve this problem, the paper achieves region of interest coding method for color image based on Shape-Adaptive All Phase Biorthogonal Transform (SA-APBT) and MPEG-4 video object coding algorithm based on SA-APBT.Before the object-based coding, firstly the image or video is segmented. Based on Mallat algorithm and the analysis about the properties of anti-symmetrical biorthogonal wavelet filter banks with the same even length, the paper achieves multiscale edge detection algorithm using anti-symmetrical biorthogonal wavelet filter banks with the same even length. The experimental results show that the proposed algorithm has good edge detection performance and anti-noise performance. On this basis, a new image segmentation method is proposed by combined with operation of morphology.For region of interest coding method for color image based on SA-APBT, the contour and texture including region of interest and background obtained by image segmentation are encoded. The contour uses chain code for shape coding. SA-APBT and uniform quantization are adopted for texture coding instead of SA-DCT and quantization table in JPEG. The reconstructed image achieves better effects including subjective quality and objective quality at low bit rates.For MPEG-4 video object coding based on SA-APBT, the motion, shape and texture of all video objects obtained by video segmentation are encoded in accordance with priority. On the basis of MPEG-4 video object coding using SA-DCT, the paper achieves a new MPEG-4 video object coding algorithm using SA-APBT. The proposed algorithm adopts context arithmetic coding in shape coding and SA-APBT in texture coding. In quantization step uniform quantization method takes the place of the complex quantization table in MPEG-4. The experimental results show that better video sequence reconstruction quality is achieved.The new object-based color image coding and MPEG-4 video coding algorithm which are achieved in the paper, improve coding performance and reduce the computational complexity by using uniform quantization. It is easier for hardware implementation.