Adaptive directional lifting-based wavelet transform for image coding
Adaptive directional lifting-based wavelet transform for image coding
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DOI：
10.1109/tip.2006.888341
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发表时间：
2007-02-01
影响因子：
10.6
通讯作者：
Li, Houqiang
中科院分区：
文献类型：
--
作者：
Ding, Wenpeng;Wu, Feng;Li, Houqiang
我们提出了一种新颖的图像编码中自适应方向提升（ADL）的二维小波变换方案。 ADL 不是像目前的实践那样交替应用水平和垂直提升，而是在局部窗口中沿高像素相关性的方向执行基于提升的预测。因此，它更好地适应本地窗口中的图像方向特征。 ADL变换是通过现有的I-D小波实现的，并且无缝地集成到全局小波变换中。即使在分数像素精度级别上也可以导出 ADL 的预测和更新信号，以实现高方向分辨率，同时仍然保持完美的重建。为了增强 ADL 性能，还提出了一种率失真优化的方向分割方案，以形成和编码适应局部特征的分层图像分区。实验结果表明，所提出的基于 ADL 的图像编码技术在 PSNR 和视觉质量方面均优于 JPEG 2000，在具有丰富方向特征的图像上提高了 2.0 dB。
We present a novel 2-D wavelet transform scheme of adaptive directional lifting (ADL) in image coding. Instead of alternately applying horizontal and vertical lifting, as in present practice, ADL performs lifting-based prediction in local windows in the direction of high pixel correlation. Hence, it adapts far better to the image orientation features in local windows. The ADL transform is achieved by existing I-D wavelets and is seamlessly integrated into the global wavelet transform. The predicting and updating signals of ADL can be derived even at the fractional pixel precision level to achieve high directional resolution, while still maintaining perfect reconstruction. To enhance the ADL performance, a rate-distortion optimized directional segmentation scheme is also proposed to form and code a hierarchical image partition adapting to local features. Experimental results show that the proposed ADL-based image coding technique outperforms JPEG 2000 in both PSNR and visual quality, with the improvement up to 2.0 dB on images with rich orientation features.