| 1. | Third , using singular points and direction image , we class the fingerprint . we dispart four small fields in the center field of the fingerprint image . through the directions of the lines in every small field , we confirm the fingerprint type 基于方向图分类法中将中心区域的方向图分为左上,左下,右上和右下四个子区域,根据各子区的纹线走向来确定指纹类型。 |