High-pass filter#Image

The high pass filter is a method for sharpening images. The filter searches the edges in the image, that is, places great differences in brightness. These edges receives the filter in one - adjustable in most programs - radius, the rest of the image appears as a featureless, gray surface.

Problems may arise if the method is to be used heavily. It then forms around a glowing edge around the highlighted contours. Also the image are thus adds no new information, just improves the subjective impression of sharpness.

Example

For example, consider an image that appears blurry due to lack of contrast.

2 high-pass representation, Radius: 5 pixels. Near the edges was obtained with a radius of 5 pixels, the rest of the image is reduced to a shaded area

3 final by Overlay of high-pass representation and output image