#define CANNY_SIGMA_DEF 1.0#define CANNY_PASSES_DEF 30#define CANNY_H_PERC_DEF 30.0#define CANNY_THR_FACTOR 0.5#define MAX_FILENAME_CHAR 500#define CUTOFF .001#define MAX_GAUSS 100#define WORKSIZE 1024#define HISTOGRAM_SIZE 10000#define MAGIC_SCALE_FACTOR 3.7#define v1 img_array[row][(col + 1)]      #define v2 img_array[(row - 1)][(col + 1)]#define v3 img_array[(row - 1)][col]#define v4 img_array[(row - 1)][(col - 1)]#define v5 img_array[row][(col - 1)]#define v6 img_array[(row + 1)][(col - 1)]#define v7 img_array[(row + 1)][col]#define v8 img_array[(row + 1)][(col + 1)]#define V  img_array[row][col]#define xd xdir[row][col]#define yd ydir[row][col]extern float fconv();extern float find_thres();