Name

minmax — Min/Max algorithm for noise removal from images

Calling Sequence

Output = minmax(Input, [NSteps, StepSize, Adapt, NonAdaptThreshold,
IntMaskSize, ExtMaskSize])

Parameters

Input
a matrix containing a gray-scale image to be filtered by min/max algorithm.
NSteps
number of steps to perform. Default is 10.
StepSize
the step increment for the iterative procedure. Default is 0.05.
Adapt
indicates if the algorithm should adapt itself to the local image gray level or if it considers the NonAdaptThreshold value for defining light and dark regions. Default is FALSE.
NonAdaptThreshold
If Adapt is FALSE, intensity values greater than NonAdaptThreshold will be considered as light regions.
IntMaskSize
Size of the Internal window in which curvature values will be taken into account for deciding Min or Max curvature flow. Default is 1.
ExtMaskSize
Size of the External window in which curvature values will be taken into account for deciding Min or Max curvature flow in the Adapt mode. Default is 0.
Output
a matrix containing the filtered image.

Description

Function minmax filters a gray-scale image using curvature-guided surface evolution. Object borders remain sharp while low-scale noise is removed.

Examples

    M = gray_imread(SIPDIR+'images/noisypoly.bmp');
    subplot(1,2,1);
    imshow(M);
    new_M = minmax(M, NSteps=30);
    subplot(1,2,2);
    imshow(new_M);

Authors

Leandro Estrozi <lfestrozi (AT) if DOT sc DOT usp DOT br>

Availability

The latest version of the Scilab Image Processing toolbox can be found at

http://siptoolbox.sourceforge.net

See Also

curvature , curvature2d , mogrify