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.