一个简单的虹膜定位程序

一个简单的虹膜定位实现

%.虹膜定位程序
clear;close all;
I=imread('ip1.jpg')
 f = rgb2gray(I);
imhist(f);                       %  求图像的直方图                  
[F_Size_M F_Size_N] = size(f);   %  获取f的行和列 

T =84;     
for i = 1:F_Size_M
    for j = 1:F_Size_N
        if f(i,j) >= T
            f(i,j) = 255;
        else
            f(i,j) = 0;
        end
    end
end
imshow(f);
f = ~f;
se = strel('disk',3);
f1 = imclose(f,se);
se = strel('disk',3);
f2 = imopen(f1,se);
f3 = imfill(f2,'holes');
f4 = im2double(f3);
f4 = medfilt2(f3,[3 3]);
%  imshow(f4);

% 标记，查找，分离最大联通域

[x,num] = bwlabel(f4,4);               % 标记联通域 

% 标记每一个联通域的像素个数
for j = 1 : num
    [r,c]   = find(x == j);
    rc      = [r c];
    long(j) = size(rc,1);
end
% 查找最大联通域
max = 0;
m=0;
for i = 1 : num
    if long(i) > max
        max = long(i);
        m= i;
    end
end

% 分离最大联通域
[row column] = size(x);
for i = 1 : row
    for j = 1 : column
        if x(i,j) == m
           x(i,j) = 1;
        else
            x(i,j) = 0;
        end
    end
end
  figure,imshow(x);

% % 利用cann算子进行边缘检测，以得到单像素的边缘图像

 k = edge(x,'canny');  % 边缘检测
 [m,n] = find(k == 1); % 记录边缘的坐标
 figure,imshow(I);
D=[m,n];
row=length(D);%记录边缘点个数

[R,A,B]=circ(m,n,row);调用函数，圆拟合的定位显示


最小二乘圆拟合程序
 function [R,A,B]=circ(x,y,N) 
  x1 = 0;           %给定初值
  x2 = 0; 
  x3 = 0; 
  y1 = 0; 
  y2 = 0;
  y3 = 0;
  x1y1 = 0;
  x1y2 = 0;
  x2y1 = 0; 
  for i = 1 : N            %公式计算
      x1 = x1 + x(i);     
      x2 = x2 + x(i)*x(i);   
      x3 = x3 + x(i)*x(i)*x(i);   
      y1 = y1 + y(i);
      y2 = y2 + y(i)*y(i);   
      y3 = y3 + y(i)*y(i)*y(i); 
      x1y1 = x1y1 + x(i)*y(i);  
      x1y2 = x1y2 + x(i)*y(i)*y(i);   
      x2y1 = x2y1 + x(i)*x(i)*y(i);
  end 
  C = N * x2 - x1 * x1;
  D = N * x1y1 - x1 * y1; 
  E = N * x3 + N * x1y2 - (x2 + y2) * x1; 
  G = N * y2 - y1 * y1;  
  H = N * x2y1 + N * y3 - (x2 + y2) * y1;
  a = (H * D - E * G)/(C * G - D * D);
  b = (H * C - E * D)/(D * D - G * C); 
  c = -(a * x1 + b * y1 + x2 + y2)/N;
  A = a/(-2);          %y坐标 
  B = b/(-2);          %x坐标
R = sqrt(a * a + b * b - 4 * c)/2; 
  hold on; 
alpha=0:pi/20:2*pi;%角度[0,2*pi] 
y=A+R*cos(alpha);
x=B+R*sin(alpha);
plot(B,A,'b-');     %标注圆心
hold on
plot(x,y,'r');      %圆显示