Lossy to Lossless Image Coding Using Allpass Filters

使用全通滤波器从有损到无损图像编码

• 批准号: 18500076
• 负责人: ZHANG Xi
• 金额: $ 1.86万
• 依托单位: The University of Electro-Communications
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18500076/
• 关键词: Image Coding; Wavelets; Allpass Filter; Lossy Coding; Lossless Coding; 直交ウェーブレット; 対称ウェーブレット

Wavelet-based image coding has been extensively studied and adopted in the international standard JPEG2000. In the wavelet-based image coding, two-band PR (perfect reconstruction) filter banks play a very important role. The analysis and synthesis filters are required to have exactly linear phase responses (corresponding to symmetric wavelet bases), allowing us to use the symmetric extension method to accurately handle the boundaries of images. The wavelet filter banks should also be orthonormal to avoid redundancy between the subband images. Unfortunately, there are no nontrivial orthonormal symmetric wavelets with FIR filters, except for the Haar wavelet. To achieve better compression performance, a reasonable regularity is necessary for wavelet bases. Therefore, at least one of the above-mentioned conditions has to be given up to get more regularity than the Haar wavelet. For example, the D-9/7 and D-5/3 wavelets supported by the baseline codec of JPEG2000 are biorthogonal. On the other hand, it is known that IIR, wavelet filters can simultaneously satisfy both of the orthonormality and symmetry. A class of IIR orthonormal symmetric wavelets has been proposed by using allpass filters.We apply the allpass-based orthonormal symmetric wavelets to image compression, and propose an effective implementation of the wavelet filter banks. Firstly, we present the implementation of irreversible real-to-real wavelets and show its decomposition process by using allpass filters. Then, we make use of the invertible implementation of allpass filters to realize the reversible integer-to-integer wavelets. Finally, we investigate the coding performance of the allpass-based orthonormal symmetric wavelets by using the reference software of JPEG2000, and compare the performance with the D-9/7 and D-5/3 wavelets. It is shown from the experimental results that the allpass-based orthonormal symmetric wavelets can achieve better compression performance than the D-9/7 and D-5/3 wavelets.

基于小波的图像编码已被广泛研究并被国际标准JPEG2000采用。在基于小波的图像编码中，双带PR（完美重构）滤波器组发挥着非常重要的作用。分析和合成滤波器需要具有精确的线性相位响应（对应于对称小波基），使我们能够使用对称扩展方法来准确处理图像的边界。小波滤波器组还应该是正交的，以避免子带图像之间的冗余。不幸的是，除了 Haar 小波之外，不存在具有 FIR 滤波器的非平凡正交对称小波。为了获得更好的压缩性能，小波基需要合理的正则性。因此，至少必须放弃上述条件之一才能获得比 Haar 小波更好的规律性。例如，JPEG2000的基线编解码器支持的D-9/7和D-5/3小波是双正交的。另一方面，众所周知，IIR小波滤波器可以同时满足正交性和对称性。利用全通滤波器提出了一类IIR正交对称小波。我们将基于全通的正交对称小波应用于图像压缩，并提出了小波滤波器组的有效实现。首先，我们介绍了不可逆实数小波的实现，并使用全通滤波器展示了其分解过程。然后，我们利用全通滤波器的可逆实现来实现可逆的整数到整数小波。最后，利用JPEG2000参考软件研究了基于全通的正交对称小波的编码性能，并与D-9/7和D-5/3小波进行了性能比较。实验结果表明，基于全通的正交对称小波能够比D-9/7和D-5/3小波获得更好的压缩性能。

项目成果

Design of Flat Delay IIR Filters with Flat Passband and Equiripple Stopband Magnitude Responses

具有平坦通带和等波纹阻带幅度响应的平坦延迟 IIR 滤波器的设计

• 发表时间: 2007
• 期刊: IEICE Trans. Fundamentals J90-A-7
• 作者: X.;Zhang;M.;Aizawa;T.;Yoshikawa
• 通讯作者: Yoshikawa

Computational Complexity Reduction for Allpass-based Image Coding

基于全通的图像编码的计算复杂度降低

• 发表时间: 2007
• 作者: K.;Ohno;X.;Zhang
• 通讯作者: Zhang

通過域平たん阻止域等リプル振幅特性をもつ平たん群遅延IIRフィルタの-設計法

具有通带平坦阻带等波纹幅度特性的平坦群时延IIR滤波器的设计方法

• 发表时间: 2007
• 期刊: 電子情報通信学会論文誌(A) J90-A
• 作者: 張煕;相澤正智;吉川敏則
• 通讯作者: 吉川敏則

Hilbert Transform Pairs of Orthonormal Symmetric Wavelet Bases Using Allpass Filters

使用全通滤波器对正交对称小波基进行希尔伯特变换

• 发表时间: 2007
• 作者: X. Zhang;D. F. Ge
• 通讯作者: D. F. Ge

Closed-Form Design of Maxflat R-Regular IIR Mth-Band Filters

Maxflat R-Regular IIR Mth-Band 滤波器的闭式设计

• 发表时间: 2007
• 作者: H. Takamizawa;他;X. Zhang
• 通讯作者: X. Zhang