Reconstruction of Smooth 3D Color Functions from Keypoints: Application to Lossy Compression and Exemplar-Based Generation of Color LUTs

David Tschumperlé, Christine Porquet, Amal Mahboubi

Abstract: Three-dimensional (3D) CLUTs (color lookup tables) are popular digital models used in artistic image and video processing for color grading, simulation of analog films, and more generally the description and application of generic nonparametric color transformations. The relatively large size of these models leads to high data storage requirements when trying to distribute them on a large scale (e.g., several hundred at a time). In this article, an effective technique based on a multiscale anisotropic diffusion scheme is proposed, for the lossy compression of generic CLUTs regularly sampled on a 3D grid. Our method exhibits high average compression rates, while ensuring visually indistinguishable differences with the original (uncompressed) CLUTs. In a second step, a variation of our algorithm for exemplar-based generation of CLUTs is developed in order to create a complete CLUT from a single pair of before/after images that accounts for the color transformation.