www.pudn.com > jiaozheng.rar > Yuan.m

function [X0,Y0,R]=Yuan(rgb)  %定义函数，获得圆形区域的圆心坐标及半径 
r=rgb(:,:,1); 
g=rgb(:,:,2); 
b=rgb(:,:,3); 
I=0.59*r+0.11*g+0.3*b; %像素亮度计算公式 
I=uint8(I); 
[Height,Width]=size(I); 
Thre=46;  %预设阈值 
 
for Row1=1:(Height/2);  %循环寻找圆形区域上边界   
 
    CurRow_Bright=I(Row1,:); 
    Max=max(CurRow_Bright); %求取最大亮度值 
    Min=min(CurRow_Bright); %求取最小亮度值 
    Lim=Max-Min;  %该扫描线的极限亮度差 
     if (Lim>Thre), 
         Ytop=Row1; 
         break; 
     end 
      
end 
      
for Row2=Height:-1:(Height/2);  %循环寻找圆形区域下边界   
     
    CurRow_Bright=I(Row2,:); 
    Max=max(CurRow_Bright); %求取最大亮度值 
    Min=min(CurRow_Bright); %求取最小亮度值 
    Lim=Max-Min;  %该扫描线的极限亮度差 
     if (Lim>Thre) 
         Ybot=Row2; 
         break; 
     end 
      
end 
  
for Col1=1:(Width/2);  %循环寻找圆形区域左边界   
    
    CurCol_Bright = I(:,Col1); 
    Max=max(CurCol_Bright); %求取最大亮度值 
    Min=min(CurCol_Bright); %求取最小亮度值 
    Lim=Max-Min;  %该扫描线的极限亮度差 
     if (Lim>Thre), 
         Xleft=Col1; 
         break; 
     end 
      
end 
 
for Col2=Width:-1:Width/2;  %循环寻找圆形区域右边界   
    
    CurCol_Bright = I(:,Col2); 
    Max=max(CurCol_Bright); %求取最大亮度值 
    Min=min(CurCol_Bright); %求取最小亮度值 
    Lim=Max-Min;  %该扫描线的极限亮度差 
     if (Lim>Thre), 
         Xrig=Col2; 
         break; 
     end 
          
end 
 
X0=(Xleft+ Xrig)/2; 
Y0=(Ytop+Ybot)/2; 
Rx=floor((Xrig-Xleft)/2); 
Ry=floor((Ytop-Ybot)/2); 
R=max(Rx,Ry); 
%  
% rgb(Ytop,Xleft:Xrig,1)=255; 
% rgb(Ytop,Xleft:Xrig,2)=0; 
% rgb(Ytop,Xleft:Xrig,3)=0; 
%  
% rgb(Ybot,Xleft:Xrig,1)=255; 
% rgb(Ybot,Xleft:Xrig,2)=0; 
% rgb(Ybot,Xleft:Xrig,3)=0; 
%  
% rgb(Ytop:Ybot,Xleft,1)=255; 
% rgb(Ytop:Ybot,Xleft,2)=0; 
% rgb(Ytop:Ybot,Xleft,3)=0; 
%  
% rgb(Ytop:Ybot,Xrig,1)=255; 
% rgb(Ytop:Ybot,Xrig,2)=0; 
% rgb(Ytop:Ybot,Xrig,3)=0; 
%  
% figure,imshow(rgb);