基于纹理的自适应提升小波变换图像压缩  

Adaptive Lifting Wavelet Transform and Image Compression Via Texture

作　　者：张军[1] 成礼智[2] 杨海滨[1] 黄魁华[1] 

机构地区：[1]国防科学技术大学信息系统与管理学院,长沙410073 [2]国防科学技术大学理学院,长沙410073

出　　处：《计算机学报》2010年第1期184-192,共9页Chinese Journal of Computers

摘　　要：经典二维小波变换仅在图像的水平和竖直方向应用小波滤波,不能提供灵活的方向信息,对纹理信息丰富的自然图像稀疏化效果不理想,在基于小波变换的图像压缩中还需改进.为了实现更有效的图像的稀疏表示,文中提出一种新型的基于图像纹理的自适应提升小波变换:根据局部特征将图像自适应分块,预先判断局部图像纹理方向,保持正交性质不变;沿纹理方向应用小波滤波,结合提升变换格式实现即位运算;沿纹理方向插值获取分数像素值,保护纹理信息不被破坏,总体变换对图像纹理描述更有效;结合JPEG2000中的编码方法EBCOT,对变换系数和方向信息分别编码,应用于图像压缩.仿真实验是在数值结果和视觉效果上将文中方法和JPEG2000方法作比较,以体现文中方法的优越性.Natural images are rich in texture, while the conventional wavelet transform apply horizontal and vertical filtering, which fails to provide an efficient representation for image directional features. The wavelet can＇t achieve ideal sparse representation for natural images, which conclude some defects in image compression. This paper proposes a new adaptive DWT via image texture. Partitioning the image based on local content, predicting the texture direction of local image, keeping the orthogonal property, applying directional wavelet filtering, the method is a chieved by lifting structure with in place operation. The texture is protected in getting subpixel by interpolating along predicted direction. The method can be used to construct a new image coder with the EBCOT that was adopted in JPEG2000, coding the coefficients and directional information respectively. The result of our method is more efficient for representation of natural images. The experiments of compression show that the numerical result and visual effect are improved by comparing to the conventional wavelet transform.

关 键 词：图像压缩 自适应提升小波变换 图像纹理 方向预测 像素插值 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]