/* sim_cor.c */
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "mypgm.h"


void copy_image1_to_image2()
{
  int x, y;
  
  x_size2 = x_size1;
  y_size2 = y_size1;
  
  printf("image1 is copied to image2\n\n");
  for (y = 0; y < y_size2; y++)
    for (x = 0; x < x_size2; x++)
      image2[y][x] = image1[y][x];
}


void sim_cor()
     /* Input: image1[y][x] & image2[y][x] ---- 
        Output: simple correlation value of two gray-scale images */
{
  int x, y;
  double product_sum, norm1, norm2, sim_cor;
  
  product_sum = 0.0;
  norm1 = 0.0;
  norm2 = 0.0;
  for (y = 0; y < y_size2; y++)
    for (x = 0; x < x_size2; x++) {
      product_sum += (double)image1[y][x] * image2[y][x];
      norm1 += pow((double)image1[y][x], 2);
      norm2 += pow((double)image2[y][x], 2);
    }
  
  sim_cor = product_sum / (sqrt(norm1)*sqrt(norm2));
  
  printf("Simple correlation value = %.3f\n\n", sim_cor);
}



main( )
{
  load_image_data();        /* Input of first image */
  copy_image1_to_image2();  /* Storing image1 into image2 */
  load_image_data();   /* Input of second image */
  sim_cor();           /* simple correlation matching of two images */
  return 0;
}