几种三层小波提升方案及其在图像压缩中的应用

1 引言小波理论在图像压缩中已有成功的应用。在小波压缩系统中,有两个因素是至关重要的:一是小波滤波器,二是压缩编码算法。随着小波变换进入JPEG2000,与小波变换相配套的零树编码算法写进MPEG-4,小波理论在图像压缩中也占有越来越重要的地位。基于提升算法的第二代小波变换也日益受到研究者的广泛关注。与第一代小波变换相比,提升算法具有快速、高效的优点,并且提升滤波器的设计可直接在空域中完成。第一代小波变换可通过因数分解转换为提升方案,例如著名的Cohen和

Several Three Stage Lifting Scheme in Wavelet Transforms and Image Compression

Wavelet transforms via lifting scheme are called the second-generation wavelet transforms. However, the coefficients of lifting schemes are transformed using mathematical method from the first-generation wavelets, in most design results the lifting filters are not only hard to get and also fixed. In this paper, Several three stage lifting schemes are achieved and designed. All lifting filters are designed in spatial domain and proper mathematical methods are selected. Our designed coefficients are flexible and can be adjusted according to different data. We give the mathematical design details in this paper. Finally, all designed models of lifting are used in image compression and satisfactory results are achieved.