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filename='j1.jpg';
I=im2gray(filename);%调用自编函数读取图像，并转化为灰度图象；
tic   %计时开始
[height,width]=size(I);%求行数
%预处理
I_edge=zeros(height,width);
for i=1:width-1
    I_edge(:,i)=abs(I(:,i+1)-I(:,i));
end

I_edge=(255/(max(max(I_edge))-min(min(I_edge))))*(I_edge-min(min(I_edge)));

[I_edge,y1]=select(I_edge,height,width);   %%%%%%调用select函数进行二值化

BW2 = I_edge;%

%%%%%%%%%%%%%%%%一些形态学处理
SE=strel('rectangle',[10,10]);
IM2=imerode(BW2,SE);
IM2=bwareaopen(IM2,20);
IM3=imdilate(IM2,SE);
%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%投影以粗略估计车牌位置
p_h=projection(double(IM3),'h');                %调用projection函数
if(p_h(1)>0)
    p_h=[0,p_h];
end
p_v=projection(double(IM3),'v');                %调用projection函数
if(p_v(1)>0)
    p_v=[0,p_v];
end

%%%%%%
p_h=double((p_h>5));
p_h=find(((p_h(1:end-1)-p_h(2:end))~=0));
len_h=length(p_h)/2;
%%%%%
p_v=double((p_v>5));
p_v=find(((p_v(1:end-1)-p_v(2:end))~=0));
len_v=length(p_v)/2;
%%%%%%%%%%%


%%%%%%%%%%%%%%%%%粗略计算车牌候选区
k=1;
for i=1:len_h
    for j=1:len_v
        s=IM3(p_h(2*i-1):p_h(2*i),p_v(2*j-1):p_v(2*j));
        if(mean(mean(s))>0.1)
            p{k}=[p_h(2*i-1),p_h(2*i)+1,p_v(2*j-1),p_v(2*j)+1];
            k=k+1;
        end
    end
end
k=k-1;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%%%%%%%%%%%%%%进一步缩小车牌候选区
for i=1:k
   edge_IM3=double(edge(double(IM3(p{i}(1):p{i}(2),p{i}(3):p{i}(4))),'canny'));%边缘检测调用CANNY算法因子
%图象的边缘是指图象局部区域亮度变化显著的部分图象边缘检测必须满足两个条件：一能有效地抑制噪声；二必须尽量精确确定边缘的位置
   [x,y]=find(edge_IM3==1);
   p{i}=[p{i}(1)+min(x),p{i}(2)-(p{i}(2)-p{i}(1)+1-max(x)),...
         p{i}(3)+min(y),p{i}(4)-(p{i}(4)-p{i}(3)+1-max(y))];
   p_center{i}=[fix((p{i}(1)+p{i}(2))/2),fix((p{i}(3)+p{i}(4))/2)];
   p_ratio(i)=(p{i}(4)-p{i}(3))/(p{i}(2)-p{i}(1));
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%对上面参数和变量的说明：p为一胞元，用于存放每个图像块的左上和右下两个点的坐标；
%存放格式为：p{k}=[x1,x2,y1,y2]；x1,x2分别为行坐标，y1,y2为列坐标
%p_center为一胞元,用于存放每个图像块的中心坐标,p_center{k}=[x,y];x,y分别为行,列坐标
%p_ratio为一矩阵，用来存放图像块的长宽比例
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



%%%%%%%%%%合并临近区域%%%%%%%
%如果有多个区域则执行合并
if k>1
    n=0;
    ncount=zeros(1,k);
    for i=1:k-1
        %%%需要调整if条件中的比例
        %%%需要调整
        %检查是否满足合并条件
        if(abs(p{i}(1)+p{i}(2)-p{i+1}(1)-p{i+1}(2))<=height/30&&abs(p{i+1}(3)-p{i}(4))<=width/15)
            p{i+1}(1)=min(p{i}(1),p{i+1}(1));
            p{i+1}(2)=max(p{i}(2),p{i+1}(2));
            p{i+1}(3)=min(p{i}(3),p{i+1}(3));
            p{i+1}(4)=max(p{i}(4),p{i+1}(4));  %向后合并
            n=n+1;
            ncount(n)=i+1;
        end
    end
    %如果有合并，求出合并后最终区域
    if(n>0)
        d_ncount=ncount(2:n+1)-ncount(1:n);%避免重复记录临近的多个区域。
        index=find(d_ncount~=1);
        m=length(index);
        for i=1:m
            pp{i}=p{ncount(index(i))};
            
            %pp_center{i}=p_center{ncount(i)};
            
            %重新记录合并区域的比例
            pp_ratio(i)=(pp{i}(4)-pp{i}(3))/(pp{i}(2)-pp{i}(1));     
        end
        p=pp;%更新区域记录
        p_ratio=pp_ratio; %更新区域比例记录
        clear pp;clear pp_ratio; %清除部分变量
    end
end
k=length(p); %更新区域个数
%%%%%%%%%%%%%%合并结束%%%%%%%%%%%%%%%%%%%%%



%%%%%%%%根据区域比例判断是否为车牌区域%%%%%%%%%%%%
m=1;T=0.6*max(p_ratio);%0.8参数需要调整
for i=1:k
    if(p_ratio(i)>=T&p_ratio(i)<20)
        p1{m}=p{i};
        m=m+1;
    end
end
p=p1;clear p1;
k=m-1;   %更新区域数
%%%%%%%%%%%判定结束%%%%%%%%%%%%%%%%%%%%%



toc                                  %计时结束

clear edge_IM3;clear x; clear y;     % 清空部分变量

%%%%%%%%%%%%%%%%显示
figure;
subplot(221);imshow(I);
subplot(222);imshow(BW2);
subplot(223);imshow(IM2);
subplot(224);imshow(IM3);

%%%%%%%%%%%%%%%%%显示
figure;
for i=1:k
    subplot(1,k,i);
    index=p{i};
    imshow(I(index(1)-2:index(2),index(3):index(4)));
end
if(k==1)
    imwrite(I(index(1)-2:index(2),index(3):index(4)),'cp.jpg');
end
 %存储车牌图像           
%%%%%%%%%%%%%%%%

%figure;
%I1=I.*uint8(IM3);imshow(I1)