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.