Unsharp masking is an image enhancement technique used to obtain a Modulation Transfer Function (MTF) greater than unity within a given spatial frequency band. In unsharp masking, the mask forms a slightly blurred version of the original image. The result is more severe in the high frequency region than at low frequencies. The final image is made by combining the original positive and the blurred negative images. The subjective quality of images resulting from unsharp masking is a function of the frequency response of the human eye. This study evaluates the unsharp masking technique by implementing the Subjective Quality Factor (SQF) criterion
