text: /* uncomment to enable sobel edge detection instead of 
   * roberts edge detection.
   */
  // #define SOBEL
  
  /* uncomment to use linked list instead of dynamic array,
   * the dynamic array is two times faster than the linked 
   * list with average sized images.
   */
  // #define LINKEDLIST
  
  /* uncomment to enable debugging information.
   */
  #define DEBUG
  
  /* uncomment to enable recursive hysteresis thresholding
   * rather than simple hysteresis thresholding.
   */
  #define RECURSIVE
  
  /* set the intensifying/disintensifying factor of the 
   * gradient magnitude images, if SOBEL is enabled, 
   * disintensification will be used, if roberts then 
   * intensification will be used.
   */
  #define FACTOR 2
  
  