Shahnaz R, Walkup J F, Krile T F
Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, Texas 78711-1084, USA.
Appl Opt. 1999 Sep 10;38(26):5560-7. doi: 10.1364/ao.38.005560.
The performance of an image compression scheme is affected by the presence of noise, and the achievable compression may be reduced significantly. We investigated the effects of specific signal-dependent-noise (SDN) sources, such as film-grain and speckle noise, on image compression, using JPEG (Joint Photographic Experts Group) standard image compression. For the improvement of compression ratios noisy images are preprocessed for noise suppression before compression is applied. Two approaches are employed for noise suppression. In one approach an estimator designed specifically for the SDN model is used. In an alternate approach, the noise is first transformed into signal-independent noise (SIN) and then an estimator designed for SIN is employed. The performances of these two schemes are compared. The compression results achieved for noiseless, noisy, and restored images are also presented.
图像压缩方案的性能会受到噪声存在的影响，并且可实现的压缩率可能会显著降低。我们使用JPEG（联合图像专家组）标准图像压缩方法，研究了特定的信号相关噪声（SDN）源，如胶片颗粒噪声和散斑噪声对图像压缩的影响。为了提高压缩率，在应用压缩之前，对有噪声的图像进行预处理以抑制噪声。采用了两种噪声抑制方法。一种方法是使用专门为SDN模型设计的估计器。另一种方法是先将噪声转换为信号无关噪声（SIN），然后使用为SIN设计的估计器。比较了这两种方案的性能。还给出了无噪声、有噪声和恢复图像的压缩结果。
