Heterogeneity-Projection Hard-Decision Color Interpolation Using Spectral-Spatial Correlation

This paper presents a novel heterogeneity-projection hard-decision (HPHD) color interpolation procedure for reproduction of Bayer mosaic images. The proposed algorithm aims to estimate the optimal interpolation direction and perform hard-decision interpolation, in which each pixel only needs to be interpolated once. A new heterogeneity-projection scheme based on a novel spectral-spatial correlation concept is proposed to estimate the best interpolation direction directly from the original mosaic image. Using the proposed heterogeneity-projection scheme, a hard-decision rule can be decided before performing the interpolation. The advantage of this scheme is that it provides an efficient way for decision-based algorithms to generate improved results using fewer computations. Compared with three recently reported demosaicing techniques, Gunturk´s, Lu´s, and Li´s methods, the proposed HPHD outperforms all of them in both PSNR values and S-CIELAB DeltaE_ab ^* measures by utilizing 25 natural images from Kodak PhotoCD