Edge strength filter based color filter array interpolation. 
For economic reasons, most digital cameras use color filter arrays instead of beam splitters to capture image data.  As a result of this, only one of the required three color samples becomes available at each pixel location and the other two need to be interpolated.  This process is called Color Filter Array (CFA) interpolation or demosaicing.  Many demosaicing algorithms have been introduced over the years to improve subjective and objective interpolation quality.  We propose an orientation-free edge strength filter and apply it to the demosaicing problem.  Edge strength filter output is utilized both to improve the initial green channel interpolation and to apply the constant color difference rule adaptively.  This simple edge directed method yields visually pleasing results with high CPSNR.