/* FFT2fltr.c */
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "mypgm.h"
#include "FFT1.h"
#include "FFT2.h"

void lowpass_filtering( )
     /* ex. lowpass filtering */
{
  int i, j, limit;
  
  printf("\nLowpass filtering is applied to FFT coefficients.\n");
  limit = num_of_data / 8;
  for (i = 0; i < num_of_data; i++) {
    for (j = 0; j < num_of_data; j++) {
      if ((limit < i) && (i < (num_of_data - limit)) ||
	  (limit < j) && (j < (num_of_data - limit))) {
	data[i][j] = 0.0;
	jdata[i][j] = 0.0;
      }
    }
  }
}


main( )
{
  load_image_data( );     /* Input image load      */
  make_original_data( );  /* FFT arrays generation   */
  FFT2(1);                /* 2-d FFT  */
  lowpass_filtering( );   /* filtering in frequency domain */
  FFT2(-1);               /* 2-d inverse FFT */
  make_output_image( );   /* Image generation after IFFT */
  save_image_data( );     /* Output image save */
  return 0;
}