提升小波变换二叉树图像编码算法

为进一步提高图像压缩质量,在研究二维离散信号采样的基础上,基于全相位列率滤波理论设计了全相位内插滤波器组,并将其用作小波变换提升格式中的预测和更新滤波器,对图像进行不可分离的二维小波变换.结合各分解子带小波系数金字塔排列的特点,借鉴经典的SPIHT小波编码算法的思想,提出了二叉树小波编码算法.对经典测试图像的实验结果表明,与SPIHT算法在相同编码比特率下做比较,在低比特率下,二叉树小波编码算法重建图像的峰值信噪比平均提高约0.5 dB,并且重建图像的主观质量也较好.

Binary Tree Image Coding Algorithm Based on Wavelet Transform via Lifting Scheme

To improve the quality of image compression,the sampling of two-dimensional discrete signal was discussed.All phase interpolation filter banks were designed based on the theory of all phase sequency filtering.By using the filters as the prediction and update filters in wavelet lifting scheme,the nonseparable two-dimensional wavelet transform for images was introduced in detail.Considering the characteristics of wavelet coefficients in all decomposition subbands and the basic idea of classical set partitioning in hierarchical trees(SPIHT) algorithm,binary tree wavelet coding algorithm was proposed. Experimental results on test images show that compared with SPIHT algorithm at the same bit rates,the PSNR of the proposed algorithm increases by 0.5 dB at low bit rates,and the subjective quality of reconstructed images is better.