Abstract
We propose an efficient two-layer near-lossless coding method using an extended histogram packing technique with backward compatibility to the legacy JPEG standard. The JPEG XT, which is the international standard to compress HDR images, adopts a two-layer coding method for backward compatibility to the legacy JPEG standard. However, there are two problems with this two-layer coding method. One is that it does not exhibit better near-lossless performance than other methods for HDR image compression with single-layer structure. The other problem is that the determining the appropriate values of the coding parameters may be required for each input image to achieve good compression performance of near-lossless compression with the two-layer coding method of the JPEG XT. To solve these problems, we focus on a histogram-packing technique that takes into account the histogram sparseness of HDR images. We used zero-skip quantization, which is an extension of the histogram-packing technique proposed for lossless coding, for implementing the proposed near-lossless coding method. The experimental results indicate that the proposed method exhibits not only a better near-lossless compression performance than that of the two-layer coding method of the JPEG XT, but also there are no issue regarding the combination of parameter values without losing backward compatibility to the JPEG standard.
Abstract (translated)
我们提出了一种高效的两层近无损编码方法，该方法使用了一种扩展的柱状图压缩技术，与传统的jpeg标准具有向后兼容性。jpeg-xt是HDR图像压缩的国际标准，它采用了与传统jpeg标准向后兼容的两层编码方法。然而，这种双层编码方法存在两个问题。其一，对于单层结构的HDR图像压缩，其近无损性能不如其它方法好。另一个问题是，用jpeg-xt的两层编码方法，可能需要确定每个输入图像的编码参数的适当值，以获得接近无损压缩的良好压缩性能。为了解决这些问题，我们重点研究了一种考虑HDR图像直方图稀疏性的直方图填充技术。我们使用零跳量化（零跳量化）来实现所提出的近无损编码方法，这是对无损编码的直方图填充技术的扩展。实验结果表明，该方法不仅具有比jpeg-xt两层编码方法更好的近无损压缩性能，而且在不丢失对jpeg标准向后兼容性的情况下，参数值的组合也没有问题。
URL
https://arxiv.org/abs/1905.04129
