Feature-Based Color Correction of Multiview Video for Coding and Rendering Enhancement
Multiview video (MVV) consists of capturing the same scene with multiple cameras from different viewpoints. Therefore, substantial illumination and color inconsistencies can be observed between different views. These color mismatches can significantly reduce compression efficiency and rendering quality. In this paper, we propose a preprocessing method for correcting these color discrepancies in MVV. To consider the occlusion problem, our method is based on an improvement of histogram matching (HM) algorithm using only common regions across views. These regions are defined by an invariant feature detector (scale invariant feature transform), followed by random sample consensus algorithm to increase the matching robustness. In addition, to maintain temporal correlation, HM algorithm is applied on a temporal sliding window, allowing to cope with time-varying acquiring system, camera moving capture, and real-time broadcasting. Moreover, unlike always choosing the center view as the reference by default, we propose an automatic selection algorithm based on both views statistics and quality. The experimental results show that the proposed method increases coding efficiency with gains of up to 1.1 and 2.2 dB for the luminance and chrominance components, respectively. Furthermore, once the correction is performed, the color of real and rendered views is harmonized and looks very consistent as a whole.