Image filtering: Potential efficiency and current problems

The paper contains comparisons of lower bound (potential) and achieved efficiency for filtering grayscale and color images corrupted by AWGN. It is demonstrated that for complex structure images the corresponding limits are practically reached. Then, the main problems of the current stage of filter design are discussed taking into account noise models more adequate for practice, inherent properties of multicomponent (e.g. color, hyperspectral, etc.) images, and other qualitative criteria than conventional MSE or PSNR criteria.