%程序功能：實現車牌自動定位
%作者：重慶大學 田建國 QQ:363966533
%編寫時間:2007.04.10
%修改時間:2007.07.06;修改內容:增加合并區域操作，第88行開始
clear;clc;close all

filename='2.jpg';
I=im2gray(filename);%調用自編函數讀取圖像，并轉化為灰度圖象；


tic   %計時開始

[height,width]=size(I);
%預處理
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);   %%%%%%調用select函數

BW2 = I_edge;%

%%%%%%%%%%%%%%%%一些形態學處理
SE=strel('rectangle',[10,10]);
IM2=imerode(BW2,SE);
IM2=bwareaopen(IM2,20);
IM3=imdilate(IM2,SE);
%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%投影以粗略估計車牌位置
p_h=projection(double(IM3),'h');                %調用projection函數
if(p_h(1)>0)
    p_h=[0,p_h];
end
p_v=projection(double(IM3),'v');                %調用projection函數
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;
%%%%%%%%%%%


%%%%%%%%%%%%%%%%%粗略計算車牌候選區
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;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%%%%%%%%%%%%%%進一步縮小車牌候選區
for i=1:k
   edge_IM3=double(edge(double(IM3(p{i}(1):p{i}(2),p{i}(3):p{i}(4))),'canny'));

   [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
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%對上面參數和變量的說明：p為一胞元，用于存放每個圖像塊的左上和右下兩個點的坐標；
%存放格式為：p{k}=[x1,x2,y1,y2]；x1,x2分別為行坐標，y1,y2為列坐標
%p_center為一胞元,用于存放每個圖像塊的中心坐標,p_center{k}=[x,y];x,y分別為行,列坐標
%p_ratio為一矩陣，用來存放圖像塊的長寬比例
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



%%%%%%%%%%合并臨近區域%%%%%%%
%如果有多個區域則執行合并
if k>1
    n=0;
    ncount=zeros(1,k);
    for i=1:k-1
        %%%需要調整if條件中的比例
        %%%需要調整
        %檢查是否滿足合并條件
        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，求出合并后最終區域
    if(n>0)
        d_ncount=ncount(2:n+1)-ncount(1:n);%避免重復記錄臨近的多個區域。
        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)};
            
            %重新記錄合并區域的比例
            pp_ratio(i)=(pp{i}(4)-pp{i}(3))/(pp{i}(2)-pp{i}(1));     
        end
        p=pp;%更新區域記錄
        p_ratio=pp_ratio; %更新區域比例記錄
        clear pp;clear pp_ratio; %清除部分變量
    end
end
k=length(p); %更新區域個數
%%%%%%%%%%%%%%合并結束%%%%%%%%%%%%%%%%%%%%%



%%%%%%%%根據區域比例判斷是否為車牌區域%%%%%%%%%%%%
m=1;T=0.6*max(p_ratio);%0.8參數需要調整
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;   %更新區域數
%%%%%%%%%%%判定結束%%%%%%%%%%%%%%%%%%%%%


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%d=zeros(k+1,k+1);
%for i=1:k+1
 %   for j=i+1:k+1
        %d(i,j)=sqrt((p_center{i}(1)-p_center{j}(1))^2+(p_center{i}(2)-p_center{j}(2))^2);
  %  end
%end
%說明:d用于存放第i,j個圖像塊中心點的距離;

%T=sqrt(height^2+width^2)/10;%閾值
%[x,y]=find(d>0&d<T); 
%for i=1:length(x)
%    p{x(i)}(1)=min(p{x(i)}(1),p{y(i)}(1));
%    p{x(i)}(2)=max(p{x(i)}(2),p{y(i)}(2));
%    p{x(i)}(3)=min(p{x(i)}(3),p{y(i)}(3));
%    p{x(i)}(4)=max(p{x(i)}(4),p{y(i)}(4));
%end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

toc                                  %計時結束

clear edge_IM3;clear x; clear y;     % 清空部分變量

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

%%%%%%%%%%%%%%%%%顯示
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
 %存儲車牌圖像           
%%%%%%%%%%%%%%%%

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