Effective color interpolation in CCD color filter arrays using signal correlation

In this paper, we propose an effective color filter array (CFA) interpolation method for digital still cameras (DSCs) using a simple image model that correlates the R, G, B channels. In this model, we define the constants K-R as green minus red and K-B as green minus blue. For real-world images, the contrasts of K-R and K-B are quite flat over a small region and this property is suitable for interpolation. The main contribution of this paper is that we propose a low-complexity interpolation method to improve the image quality. We show that the frequency response of the proposed method is better than the conventional methods. Simulation results also verify that the proposed method obtain superior image quality on typical images. The luminace channel of the proposed method outperforms 6.34-dB peak SNR over bi-linear method, and the chrominace channels have a 7.69-dB peak signal-to-noise ratio improvement on average. Furthermore, the complexity of the proposed method is comparable to conventional bilinear interpolation. It requires only add and shift operations to implement.