A sharpening method that sharpens images without the graininess that appears with most other sharpening methods.
Despite the name, this is an edge enhancing filter frequently used in teleradiology. It is created by first generating a low-pass filtered image, which is then subtracted from the original image. This effectively removes part of the background, leaving an image where contours are emphasized.
a blurred duplicate of the image that is basically overlayed when printing
In Photoshop and other image-editing programs, this is a digital implementation of a traditional darkroom and prepress technique in which a blurred film negative is combined with the original to highlight the photograph's edges. In digital form, it's a more controllable method for sharpening an image than standard sharpening commands.
Unsharp mask is an image-processing technique used to sharpen an image and enhance detail. True unsharp masking is done by subtracting a blurred version of an image from the original. Unsharp mask routines in software simulate this effect and make it easier to have control over the final image.
Originally a photographic process in which a sharply focussed and a slightly out-of-focus image are combined to produce a sharper image. This process is simulated by software to produce the same effect.
A masking method done electronically to exaggerate the edges of the images and the difference between light and dark areas or hues to enhance the detail in the final reproduction. (See also Detail Contrast and Electronic Enhancement.) Also known as peaking.