float correlation_coefficient(float *image, int num_cols,int patch_x, int patch_y,int i,int j,int k,int l);
int calc_descriptor(float *image,float *descriptor, int num_rows, int num_cols, int patch_x, int patch_y, int region_x, int region_y, int region_grid_x, int region_grid_y,int n_descriptors);
