Color Filter Array Demosaicking by Using Subband Synthesis Scheme

Abstract

Digital still cameras use image sensors to capture images. To reduce the size of digital still cameras, a single image sensor instead of three image sensors should be used. A single image sensor overlaid with a color filter array (CFA) that filters color channels only captures one color channel at each pixel; thus, the other missing color channels at each pixel must be reproduced from neighboring pixels. This procedure is known as CFA interpolation or demosaicking. In this paper, a novel CFA interpolation method is proposed to reduce false color artifacts and improve the quality of restored images. First, an edge detection method is used to interpolate the initial missing color channels. Second, the high correlations between wavelet subbands of the different color channels are explored to obtain accurate color values of the estimated green channel. Finally, the high-frequency subbands of red and blue channels are iteratively updated to reduce false color artifacts. Experimental results show that our proposed method preserves edges and restores images with high quality.