Comparative study of unsharp masking methods for image enhancement

Contrast enhancement by the unsharp masking (UM) approaches are computationally and conceptually the simplest methods. In this paper, the different methods of UM for image enhancement are compared. These algorithms have been tested and compared for the same conditions. The results show that majority of these algorithms are very sensitive to the enhancement factor and are good for sharpening. This factor must be estimated recursively by considering the statistics of neighboring pixel values.