Two-layer Lossless HDR Coding considering Histogram Sparseness with Backward Compatibility to JPEG

TL;DR

This paper introduces a two-layer lossless HDR image coding method that leverages histogram sparseness and maintains backward compatibility with JPEG, outperforming JPEG XT without complex parameter tuning.

Contribution

A novel two-layer HDR coding scheme using histogram packing that improves lossless compression and simplifies parameter selection while ensuring JPEG backward compatibility.

Findings

Better lossless compression performance than JPEG XT.

No need for image-dependent parameter tuning.

Maintains backward compatibility with JPEG.

Abstract

An efficient two-layer coding method using the histogram packing technique with the backward compatibility to the legacy JPEG is proposed in this paper. The JPEG XT, which is the international standard to compress HDR images, adopts two-layer coding scheme for backward compatibility to the legacy JPEG. However, this two-layer coding structure does not give better lossless performance than the other existing single-layer coding methods for HDR images. Moreover, the JPEG XT has problems on determination of the lossless coding parameters; Finding appropriate combination of the parameter values is necessary to achieve good lossless performance. The histogram sparseness of HDR images is discussed and it is pointed out that the histogram packing technique considering the sparseness is able to improve the performance of lossless compression for HDR images and a novel two-layer coding with the histogram packing technique is proposed. The experimental results demonstrate that not only the proposed method has a better lossless compression performance than that of the JPEG XT, but also there is no need to determine image-dependent parameter values for good compression performance in spite of having the backward compatibility to the well known legacy JPEG standard.