Edge-adaptive complementary color filter array demosaicking

Complementary color filter array (CCFA) is widely used in consumer-level digital video cameras, since it has high sensitivity and good signal-to-noise ratio in low-light condition. However, the full-color images obtained from CCFA suffer from some artifacts such as false color and zipper effects. These artifacts can be removed with edge-adaptive demosaicking (EAD) approaches which are generally used in primary color filter array (PCFA). Unfortunately, the unique array pattern of CCFA makes it difficult that CCFA adopts EAD approaches. Therefore, to apply EAD approaches suitable for CCFA to demosaicking is one of the major issues to reconstruct the full-color images. In this paper, we propose a new EAD algorithm for CCFA. To estimate an edge direction precisely and enhance the quality of the reconstructed image, a function of spatial variances is used as a weight and new color conversion matrices are presented for considering various edge directions. Experimental results indicate that the proposed algorithm outperforms the conventional method with respect to both objective and subjective criteria.