Lossless two-layer coding for HDR images

A lossless two-layer coding scheme for HDR images using a histogram packing technique is proposed for HDR images in this paper. The proposed scheme has the compatibility with the legacy JPEG for base layer as well as the normative JPEG XT standard. A histogram packing technique is applied to residual images to improve the performance of lossless compression. The experimental result for the bitrates of the encoded bitstreams demonstrates that the proposed structure gives a better coding performance than the normative JPEG XT profile C.

I. Introduction

Image compression methods designed to provide coded data containing high dynamic range content is highly expected to meet the rapid growth of high dynamic range (HDR) image applications. Generally, HDR images have much greater bit depth of pixel values and much wider color gamut [1]–[6]. These characteristic of HDR images are suitable for recording and/or archiving the highly valuable contents, such as masterpieces of art. For such a valuable content, HDR images should be losslessly. In other words, they should be compressed without any loss that generated during compression procedure.