基于对象的小波变换在MPEG-4任意形状图像编码中的应用

任意形状图象对象的变换编码方法是MPEG-4视频编码实现的核心技术之一.该文对基于对象的小波变换在任意形状图象编码算法中的应用给予了详尽的论述.基于对象的小波变换包含两个步骤一是针对任意形状对象进行外插,使其可以运用规范的小波变换;二是进行小波系数的编码选择,以消除外插所产生的冗余.实验结果表明基于对象的小波变换与诸如SADCT等方法具有相似的低复杂度,性能相当;并且,在低比特率的情况下,其编码效果要优于SADCT.

Object Based Wavelet Transform for Coding of Arbitrarily Shaped Image in MPEG-4

Coding of arbitrarily shaped image is one of the core techniques in MPEG 4 video compression. One approach to transform an arbitrarily shaped image region is addressed. The proposed approach, termed object based wavelet transform (OWT), is simple to implement. It is a smooth extension of regular wavelet transform (WT). OWT consists of a two phase process: one is an extrapolation phase for regular WT and the other is a handling coefficients phase for eliminating redundancy caused by the extrapolation. Experiments shows that the performance of the method is similar to other shape adaptive approaches (for example: SADCT) with lower complexity. Especially in low bit rate, OWT is better than SADCT.