IEEE Trans Image Process. 2012 Aug;21(8):3801-06. doi: 10.1109/TIP.2012.2197015. Epub 2012 May 1.
Pulse-code modulation (PCM) with embedded quantization allows the rate of the PCM bitstream to be reduced by simply removing a fixed number of least significant bits from each codeword. Although this source coding technique is extremely simple, it has a poor coding efficiency. In this paper, we present a generalized PCM (GPCM) algorithm for images that simply removes bits from each codeword. In contrast to PCM, however, the number and the specific bits that a GPCM encoder removes in each codeword depends on its position in the bitstream and the statistics of the image. Since GPCM allows the encoding to be performed with different degrees of computational complexity, it can adapt to the computational resources that are available in each application. Experimental results show that GPCM outperforms PCM with a gain that depends on the rate, the computational complexity of the encoding, and the degree of inter-pixel correlation of the image.
脉冲编码调制（PCM）与嵌入式量化允许通过从每个码字中简单地去除固定数量的最低有效位来降低 PCM 比特流的速率。尽管这种源编码技术非常简单，但它的编码效率很差。在本文中，我们提出了一种用于图像的广义 PCM（GPCM）算法，它只是从每个码字中去除位。然而，与 PCM 不同的是，GPCM 编码器在每个码字中去除的位数和特定位取决于其在比特流中的位置和图像的统计信息。由于 GPCM 允许以不同程度的计算复杂度进行编码，因此它可以适应每个应用程序中可用的计算资源。实验结果表明，GPCM 的性能优于 PCM，增益取决于速率、编码的计算复杂度以及图像的像素间相关性程度。
