Edge-adaptive color interpolation algorithm for progressive scan charge-coupled device image sensors

The color interpolation scheme can play an important role in overcoming the physical limitation of CCD image sensors and in increasing the resolution of color signals, while most conventional approaches result in blurred edges and false color artifacts. We propose an improved edge-adaptive color interpolation scheme for a progressive scan CCD image sensor with an RGB color filter array. The proposed edge indicator function utilizes not only the within-channel correlation, but also the cross-channel correlation, and reflects the edge characteristics of an image adaptively. The color components unavailable at each channel are interpolated along the edge direction, not across the edges, so that aliasing artifacts are suppressed. Furthermore, we eliminate false color artifacts resulting from the color image formation model in the edge-adaptive color interpolation scheme by adopting the switching algorithm based on the color edge detection. Simulation results of the proposed algorithm indicate that the improved edge-adaptive color interpolation scheme produces results that are quantitatively better and visually more pleasing than those achieved by conventional approaches.