基于MATLAB的指纹指纹识别系统

参考代码：

function Fangxiangtu = zhiwen_fangxiangtu( Zhiwentuxiang )
%函数功能 计算指纹方向图
%函数参数 指纹图像 Zhiwentuxiang
%函数返回值 指纹方向图Fangxiangtu 
SizeZhiwentuxiang = size( Zhiwentuxiang ) ;
Zhiwentuxiang = double( Zhiwentuxiang ) ;
W = 4; % 窗口大小 (2W+1)*(2W+1)
W = 4;
%Sobel算子
x_fangxiang = [-1 0 1;
             -2 0 2;
             -1 0 1];
 
y_fangxiang = [1 2 1;
               0 0 0;
               -1 -2 -1];
SizeZhiwentuxiang = size( Zhiwentuxiang );
Gx = zeros( SizeZhiwentuxiang );
Gy = zeros( SizeZhiwentuxiang );
Fangxiangtu = zeros( SizeZhiwentuxiang );
for i = 2 : SizeZhiwentuxiang( 1 , 1 ) - 1
    for j = 2 : SizeZhiwentuxiang( 1, 2 ) - 1
        Sum_x = 0;%j方向
        Sum_y = 0;%i方向
        for k = -1 : 1
            for r = -1 : 1
                Sum_x = Sum_x + x_fangxiang( k + 2 , r + 2 ) * Zhiwentuxiang( i + k , j + r  );
                Sum_y = Sum_y + y_fangxiang( k + 2 , r + 2 ) * Zhiwentuxiang( i + k , j + r  ); 
            end
        end
        Gx( i , j ) = Sum_x ;
        Gy( i , j ) = Sum_y ;
    end
end
for i = W+1 : SizeZhiwentuxiang( 1 , 1 ) - W
    for j = W+1 : SizeZhiwentuxiang( 1, 2 ) - W
        Vx = 0;
        Vy = 0 ;
        for io = -W : W
            for jo = -W : W
                Vy = Vy + 2 * Gx( i + io , j + jo ) * Gy( i + io , j + jo );
 
            end
        end
        if Vx ~= 0
            th = atan( Vy / Vx ) / 2 ;
            Fangxiangtu( i , j ) = th ;
        else
            Fangxiangtu( i , j ) = pi / 2;
        end
    end
end