/* minutiae.c */
/* extraction of minutiae candidates in skeletonized fingerprint image */
#include <stdio.h>
#include <stdlib.h>
#include "mypgm.h"

#define BLACK 0
#define WHITE 255
#define GRAY 200

/* prototype declaration */
void minutiae();
int crossnumber(int, int);


int main( )
{
  load_image_data( ); /* loading image1 */
  minutiae( );        /* extracting minutiae candidates */
  save_image_data( ); /* saving image2 */
  return 0;
}


void minutiae()
{
  int x, y;
  int total, np1, np2;  /* number of black and minutiae points */
  int cross;
  
  /* initialization of output image */
  x_size2 = x_size1;
  y_size2 = y_size1;
  for (y = 0; y < y_size2; y++) {
    for (x = 0; x < x_size2; x++) {
      if (image1[y][x] == BLACK) {
	image2[y][x] = GRAY;
      } else {
	image2[y][x] = WHITE;
      }
    }
  }
  
  /* finding minutiae in 3 x 3 window */
  printf("Minutiae extraction is applied to skeletonized fingerprint.\n");
  total = 0;
  np1 = 0;  /* number of ending points */
  np2 = 0;  /* number of bifurcations */
  for (y = 1; y < y_size1 -1; y++) {
    for (x = 1; x < x_size1 - 1; x++) {
      if (image1[y][x] == BLACK) {
	total++;
	cross = crossnumber(y, x);
	if (cross == 1) {
	  np1++;
	  image2[y][x] = BLACK;
	} else if (cross >= 3) {
	  np2++;
	  image2[y][x] = BLACK;
	}
      }
    }
  }
  printf("total number of BLACK points = %d\n", total);
  printf("number of ending points = %d\n", np1);
  printf("number of bifurcations = %d\n\n", np2);
}


int crossnumber(int y, int x)
{
  int i, data[8];
  int cross;

  data[0] = image1[y][x+1] == BLACK ? 1 : 0;
  data[1] = image1[y-1][x+1] == BLACK ? 1 : 0;
  data[2] = image1[y-1][x] == BLACK ? 1 : 0;
  data[3] = image1[y-1][x-1] == BLACK ? 1 : 0;
  data[4] = image1[y][x-1] == BLACK ? 1 : 0;
  data[5] = image1[y+1][x-1] == BLACK ? 1 : 0;
  data[6] = image1[y+1][x] == BLACK ? 1 : 0;
  data[7] = image1[y+1][x+1] == BLACK ? 1 : 0;
  cross = 0;
  for (i = 0; i < 8; i++) {
    cross += abs(data[(i+1)%8] - data[i]);
  }
  cross /= 2;
  
  return cross;
}