% Image Unsharp Mask function
% usage:
% [output_img] = imgUnsharpMask ([input_img], smoothing_mask, mpl)
% smoothing_mask - for example gaussian or average filtering mask
% mpl - multiplier for the sharpening effect (usualy 0.2 - 0.7)
% Effect depends on the filtering mask.

function [img_out] = imgUnsharpMask (img_in, smothing_mask, mpl)

img_smoth = imgFilter(img_in, smothing_mask);   % smooth ver. of image
img_out = img_in + mpl * (img_in - img_smoth);  % unsharp mask equation