基于二维APDCSF的列率子带特征编码方法

提出了一种子带编码的新方法。该方法利用二维全相位离散反余弦列率滤波器（APDCSF）对图像进行子带分解；对于低频子带图像采用直接斜交多重亚采样和基于全相位离散反余弦列牢滤波器（APDICsF）的多重旋转内插恢复．而对高频子带图像利用直方图自动阈值化提取如边缘和线等特征的图像元；根据各个子带的图像元的特征分别进行编码压缩，解压缩后利用凸集投影重建原始图像。该方法消除了传统的离散余弦变换（DCT）编码的方块化效应，与基于小波变换的子带特征编码方法相比，计算复杂度小，压缩率高，主观视觉性能好，对于灰阶图像可达到0．1～0．3bpp，特别适用于低比特率图像压缩。

Sequency Subband Feature Coding on 2-D APDCSF

A novel subband coding approach is presented in this paper.It uses the 2-D all phase discrete cosine sequency filter(APDCSF) to decompose original image into subbands;the low-pass subband image is directly multi-subasampled with a two-dimensional cross structure and interpolated with the two-dimessional rotating multi-interpolation filting based on the all phase discrete inverse cosine sequency filter(APDICSF).As to the high-pass subband images,the image primitives such as the edge and line feature are extracted by histogram automatic thresholding.Different compression coding techniques are performed respectively for the features in different subbands,and the original image can be reconstructed by convex projection.This approach with using the APDCSF can eliminate the block effects in traditional discrete cosine transform(DCT) transform coding.Compared with the subband feature coding based on wavelet transform,its computational complexity is much less and its compression rate is higher,furthermore the subjective visual effect is better than DCT transform coding.It is suitable especially for low bit rate image compression.