Unsharp Mask

Unsharp Mask Unsharpen Mask locates the pixels that differ in value from surrounding pixels by the threshold which is specified by the user and increases the pixels' contrast by an amount which is also specified by the user, so that for the neighboring pixels specified by the threshold, the lighter pixels becomes even lighter and the darker pixels becomes even darker based on the specified amount.

In addition, the user can specify the radius of the region with which each pixel will be compared. The greater the radius is, the larger the edge effects are.

To use Unsharp Mask filter:

Choose Filters > Sharpen > Unsharp Mask.