Demosaicked image postprocessing using local color ratios

A postprocessing method for the correction of visual demosaicking artifacts is introduced. The restored, full-color images previously obtained by cost-effective color filter array interpolators are processed to improve their visual quality. Based on a localized color ratio model and the original underlying Bayer pattern structure, the proposed solution impressively removes false colors while maintaining image sharpness. At the same time, it yields excellent improvements in terms of objective image quality measures.

I. Introduction

Recent times have seen the proliferation of electronic devices such as mobile telephones and personal digital assistants (PDAs) with embedded image capturing capabilities. The majority of these devices use a single charged couple device (CCD) or complementary metal–oxide–semiconductor (CMOS) sensor with a color filter array (CFA). Using the Bayer CFA pattern [1], the sensor produces a two-dimensional array with each spatial location containing only a red (R), green (G), or blue (B) component. Given that each pixel contains one color, spectral interpolation is performed to obtain a full RGB color image. The process of interpolating missing spectral components is known as demosaicking since the restored color image output is obtained using the spatially adjacent CFA data from the input mosaic of the color components [2]–[4].