pextremumsharpening

Performs constrast sharpening using extremum values.

Synopsis

pextremumsharpening [-m mask] [im_in|-] [im_out|-]

Description

pextremumsharpening performs a contrast sharpening of the input image im_in. The objective is to highlight fine detail and to enhance details that are blurred. Sharpening consists in shrinking the width of intensity variation without affecting the mean intensity of regions on both sides of the variation.

The algorithm consists in replacing a pixel by the closest neighborhood minimum or maximum values.

Let W by a neighborhood, and im_in(p) a pixel of the input image:

	if (im_in(p)-min(W) < max-im_in(p))
	then im_out[p]=min
	else im_out[p]=max

For color and multispectral images, the transform uses the marginal approach: it is applied on each band individually.

Inputs

im_in: an image.

Outputs

im_out: an image with the same properties as im_in.

Result

Returns SUCCESS or FAILURE in case of memory faults.

Examples

Sharpens the tangram.pan image.

   pextremumsharpening tangram.pan a.pan

C++ prototype

Errc PExtremumSharpening( const Img2duc &im_in, Img2duc &im_out );

Version française

Rehaussement du contraste par utilisation des valeurs extrémales.

Author: Régis Clouard