NAME

     ifft_transform - performs an inverse fast Fourier transform

SYNOPSIS

      #include <math.h>
      #include "CVIPtools.h"
      #include "CVIPimage.h"
      #include "CVIPconvert.h"
      #include "CVIPtransform.h"

     Image *ifft_transform(Image *in_Image, int block_size)

      <in_Image> - pointer to an Image structure
      <block_size> - block size used for forward transform

PATH

     $CVIPHOME/TRANSFORMS/inverse_fft.c

DESCRIPTION

     This function performs an inverse fast Fourier transform  on
     an image that has previously had a forward FFT performed.

TYPES AND CONSTANTS

     None

RETURN VALUES

     A transformed image

HISTORY

     History information recorded: None

EXAMPLE

      #include <CVIPtoolkit.h>
      #include <CVIPimage.h>
      #include <CVIPconvert.h>
      #include <CVIPview.h>
      #include <CVIPtransform.h>
      #include <math.h>
      #include <sys/file.h>
      #include <float.h>
      #include <sys/types.h>
      #include <sys/uio.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 performs a fft_transform on the
      input image with block size equal to 8 */
      cvipImage = fft_transform(cvipImage, 8);
      print_CVIP("\n\t\tEnter the Output File Name:  ");
      outputfile = getString_CVIP();
      view_Image(cvipImage,outputfile);
      /* the format is VIP because the output image type is
      complex */
      write_Image(cvipImage,outputfile,CVIP_NO,CVIP_NO,VIP,1);
      free(outputfile);
      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 performs a inverse fft_transform
      on the input image with block size equal to 8 */
      cvipImage = ifft_transform(cvipImage, 8);
      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);
      }

SEE ALSO

     libtransform, fft_transform

AUTHOR

     Copyright (C) 1996 SIUE - by Scott E. Umbaugh and Simon Low.