NAME

     fft_transform - perform fast Fourier transform

SYNOPSIS

      #include <math.h>
      #include <float.h>
      #include <sys/file.h>
      #include <sys/types.h>
      #include <sys/uio.h>
      #include <CVIPtools.h>
      #include "CVIPimage.h"
      #include "CVIPtransform.h"

     Image *fft_transform(Image *input_Image,int block_size)

      <input_Image> - pointer to an Image structure
      <block_size> - block size

PATH

     $CVIPHOME/TRANSFORMS/fft.c

DESCRIPTION

     This function performs  a  Fast  forward  Fourier  Transform
     (FFT)  on  an  image.Block  sizes  in power of two should be
     specified,otherwise segmentation fault will occur.

TYPES AND CONSTANTS

     None

RETURN VALUES

     An image pointer with complex data

HISTORY

     History information recorded: Fast Fourier Transform. Block-
     size: #

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 the fft_tranform on the
      input image with the block size being 8 */
      cvipImage = fft_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, ifft_transform

AUTHOR

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