The Research On High-fidelity Reproduction Of High Dynamic Range Images

High Dynamic Range (HDR) image belongs to scene referred encoding image, and they can reappearance the luminance range of the natural world which human vision can perceive. In image reproduction field, the reappearance of tone and color are two main critical factors which affect quality of printing reproduction. Because the tone range which ordinary output referred encoding images can represent and the gamut which the four-color printing process can reappearance are small, so using regular four-color printing process to reproduce the ordinary type image is very difficult to reappearance the tone range and color appearance of the natural world. In order to improve the quality of printing reproduction, in view of the existing current problems, this paper research high-fidelity reproduction for HDR images on the two aspects of tone reproduction and color reproduction. The research can not be only applied on high-fidelity printing reproduction directly, but also be widely used in HDR imaging and image processing fields such as remote sensing, virtual reality, medical imaging and so on.The main research contents of this paper include:(1) The existing tone reproduction algorithms for HDR images were researched and analyzed, and the fundamental framework of new algorithm were established;(2) A new tone reproduction algorithm for HDR images based on iCAM was researched and proposed, and the software module of tone reproduction for HDR images was developed by JAVA-MATLAB hybrid programming technology;(3) The existing printing color separation algorithms were researched and analyzed in order to provide the design of new high-fidelity printing color separation algorithm with theory evidence;(4) A new high-fidelity six-color separation algorithm was researched and proposed, and the corresponding software for creating CMYKOG six-color ICC profile was developed;The main innovations of this paper include:①a new tone reproduction algorithm for HDR images based on iCAM was proposed, and the new algorithm improved the existing tone reproduction algorithm in aspects of tone compress function, color appearance effect predicting and calculation speed;②a new six-color separation algorithm based on subarea Neugebauer Equation system was proposed. The new algorithm introduced the gamut compression algorithm based on the node addresses into the solving process of the Neugebauer Equation system in each subarea based on Newton-Raphson method. It successfully solved the problem that the separation of colorimetric outside the target gamut results in the abnormal value;③The six-color separation model established finally was used to create multi-color ICC profile in the form of multidimensional look-up table.