<title>Color space choice for nearly reversible image compression</title>

Abstract

In applications where nearly reversible color image compression is required, the choice of an appropriate color space is a major factor determining the attainable compression ratio.The optimal choice would satisfy the following conditions . Decorrelate the data as much as possible.. Minimize the total number of bits in the data path needed for a certain quality level (assuming a truly reversible component compression scheme). a Need no calculations with critical accuracy.We compared several known linear color transformations (under the assumption that the original data was represented in RGB) with respect to these conditions. Decorrelation and entropy reduction were calculated. The number of bits required to guarantee a certain quality level measured in SLab units was determined. The effects of transformation coefficient quantization were checked.As a result, a simple transformation needing no multipliers at all is proposed.

Color LAR Codec: A Color Image Representation and Compression Scheme Based on Local Resolution Adjustment and Self-Extracting Region Representation

“…The space selected for color representation is the traditional one for lossy coding, namely Y:Cr:Cb in 4:4:4 format. Various considerations have motivated this choice: decorrelation of information while observing Y:Cr:Cb components, uniformly distributed entropy on chromatic components [15], simplicity of this transformation and, finally, simplicity while using this representation space (linear transformation, integer values).…”

Reversible Integer Color Transform

“…• [2] and [3], the integer color transforms derived here are much more accurate (see Section VII). Compared with the advanced works in [4]- [6], [14], the improvements are: 1) the ways to save the number of time cycles for implementation (Section IV) and 2) the method to analyze the accuracy by normalized root mean square error are proposed (Section V).…”

“…Manuscript TABLE I PARAMETERS OF THE REVERSIBLE INTEGER COLOR TRANSFORMS (PART 1) II. PREVIOUS WORKS ABOUT INTEGER TRANSFORMS AND MATRIX FACTORIZATION In [2], the reversible integer RGB-to-KLA transform was introduced. In [3], the reversible integer RGB-to-YC b C r was developed.…”

“…To overcome this problem, some integer color transforms used for approximating noninteger color transforms were developed [2]- [6], [14], [15]. Manuscript TABLE I PARAMETERS OF THE REVERSIBLE INTEGER COLOR TRANSFORMS (PART 1) II.…”

“…Most of them consist of three components. Some popular and well-known ones are RGB, Karhunen-Loeve average (KLA), highest ability for color decorrelation, IV1V2, YC b Cr, DCT, YUV, and YIQ [1], [2]. In many applications, we usually have to transform one color coordinate system into another one.…”