Color lookup tables (CLUTs) that are embedded in printer firmware consume precious flash memory. In order to conserve memory and thereby reduce cost, it is desirable to compress CLUTs prior to storage and restore tables as required. In this paper, we investigate methods for lossless compression of CLUTs. We demonstrate that, through suitable pre-processing of data, significant improvements in compression performance can be obtained as compared to a direct application of lossless data compression methods. In particular, the gains in performance with the proposed methods are accomplished by exploiting the characteristics of CLUT data and utilizing a combination of hierarchical differential encoding and re-ordering for the pre-processing. Experimental results over a representative data set indicate that the proposed methods can result in a 26% reduction in memory requirements in comparison to direct compression. As compared to uncompressed tables this corresponds to a memory saving of 68%.
Aravindh Balaji, Gaurav Sharma, Mark Q. Shaw, Randall Guay, "Hierarchical Compression of Color Look Up Tables" in Proc. IS&T 15th Color and Imaging Conf., 2007, pp 261 - 266, https://doi.org/10.2352/CIC.2007.15.1.art00049