【作者】 王丽宁；

【导师】 肖志涛； 徐妮妮；

【作者基本信息】 天津工业大学 ， 信号与信息处理， 2008， 硕士

【摘要】 图像编码是数字图像处理的重要分支,广泛应用在各种图像/视频编码的传输、存储和检索系统中。自20世纪80年代以来,小波变换因其特有的多分辨率分析能力被广泛应用于图像/视频编码领域,取得了很好的效果。小波编码是变换编码新的、重要的发展方向,随着JEPG2000的推出,可以预见小波编码将成为图像/视频编码的主流技术。本论文主要研究了纯二维小波及其提升格式,以及适用于该变换的二叉树编/解码压缩算法。文中首先简要地介绍了一维小波变换、多分辨分析以及正交小波的分解与重构算法。接着研究了二维可分离小波的分解与重构算法和小波提升方案。结合小波变换图像编码的基本思想,介绍了SPIHT编码算法。基于全相位列率滤波理论,设计了全相位内插滤波器组,对其加窗得到一维加窗全相位IDCT滤波器。将设计的全相位内插滤波器用做小波提升格式中的预测和更新滤波器,详细介绍了纯二维小波变换提升格式的实现过程。经过纯二维小波变换后,分析各分解子带小波系数金字塔排列的特点,借鉴典型的SPIHT小波编码算法的思想,设计了二叉树小波编/解码算法,并详细给出了二叉树编/解码实例。最后用Matlab程序实现了图像的纯二维提升小波变换和二叉树编码算法,二叉树解码和小波反变换重建图像。对经典的测试图像做压缩,将得到的实验结果与传统的小波编码算法SPIHT做比较,在低比特率情况下,得到了好的压缩效果。更多还原

【Abstract】 The image encoding, which is a significant branch of Digital Image Processing, is extensively applied in various transmitting, storage and retrieval systems of image & video. Since 1980s, the wavelet transform has been well applied in image & video encoding fields for its special capability of Multi-Resolution Analysis. Wavelet encoding is a new and vital development direction in transform encoding. With the proclamation of JEPG2000 standard, wavelet encoding will be the mainstream technology in image & video encoding fields.In this paper, true 2-D wavelet transform and its lifting scheme and Binary Tree wavelet encoding & decoding algorithm to Image Compression which is suitable for this wavelet are mainly studied. First of all, 1-D wavelet transform, Multi-Resolution Analysis and orthogonal wavelet decomposition & reconstruction algorithm are briefly introduced. Secondly, the separable 2-D wavelet transform, its decomposition & reconstruction algorithm, and lifting scheme are discussed. With the basic idea of wavelet transform image encoding, SPIHT encoding algorithm is introduced.In the following, the sampling of 2-D discrete signal is discussed, and All Phase Interpolating Filter Banks are designed based on the theory of All Phase Sequency Filting. Using the All Phase Interpolating Filter Bank as the prediction and update filter in wavelet lifting scheme, the realization of the true 2-D wavelet transform with lifting scheme is introduced in detail. After the true 2-D wavelet transform, considering the characteristics of wavelet coefficients in all decomposition sub-bands and the basic idea of classical SPIHT wavelet encoding algorithm, Binary Tree Wavelet encoding & decoding algorithms are proposed with detailed instance.Finally, the true 2-D wavelet transform of images with lifting scheme, binary tree encoding algorithm and are realized with Matlab program. Correspondingly, binary tree decoding and wavelet inverse transform are carried out to reconstruct the images. When compressing the classical test images, the results indicate that the compression efficiency is better than the traditional wavelet encoding algorithm SPIHT at low bit rates.更多还原