## NAME

         minimum_filter - typically applied to  an  image  to  remove
         positive outlier noise.

## SYNOPSIS

          #include <CVIPtoolk.h>
          #include <CVIPdef.h>
          #include <CVIPspfltr.h>
          #include <float.h>

         Image *minimum_filter(Image *imageP, int mask_size)
             <imageP> - pointer to an Image structure.
             <mask_size> - size of the filtering  window  (e.g.,  3->
         3x3).

## PATH

         $CVIPHOME/SPATIALFILTER/spatial_filter.c

## OPTIONS

         None.

## DESCRIPTION

         Returns the minimum value of the set of pixels contained  in
         the  N x N filter window.

## TIPS

         Works best on images containing positive outlier noise. This
         filter  will  darken the appearance of the image.  Keep mask
         size small to minimize blurring.

## DIAGNOSTICS

         Returns error message if invalid  filter  size  is  entered.
         Size of filter is to be an odd integer limited from < 3 - 31
         >.

## EXAMPLE

          #include <CVIPtoolkit.h>
          #include <CVIPimage.h>
          #include <CVIPdef.h>
          #include <CVIPspfltr.h>
          #include <CVIPconvert.h>
          #include <CVIPview.h>
          #define VIEWER "picture"
          #define VIDEO_APP "SunVideo &"

          void main()
          {
          Image *cvipImage;
          IMAGE_FORMAT format;
          char *inputfile,*outputfile;

          setDisplay_Image(VIEWER, "Default");
          print_CVIP("\n\t\tEnter the  Input File Name:  ");
          inputfile =(char *) getString_CVIP();
          format = getFormat_CVIP(inputfile);
          cvipImage = read_Image(inputfile,1);
          view_Image(cvipImage, inputfile);
          free(inputfile);
          /* the following call replaces each pixel value by the
          minimum pixel value in a 3 x 3 window */
          cvipImage = minimum_filter(cvipImage,3);
          print_CVIP("\n\t\tEnter the Output File Name:  ");
          outputfile = getString_CVIP();
          view_Image(cvipImage,outputfile);
          write_Image(cvipImage,outputfile,CVIP_NO,CVIP_NO,format,1);
          free(outputfile);
          }

## BUGS

         None.

## AUTHOR

         Copyright (C) 1992, 1996 SIUE - by Scott E. Umbaugh and John
         A Creighton.