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% OCR (Optical Character Recognition).
% Author: Ing. Diego Barrag醤 Guerrero
% e-mail: diego@matpic.com
% For more information, visit: www.matpic.com
%________________________________________
% PRINCIPAL PROGRAM
warning off %#ok<WNOFF>
% Clear all
clc, close all, clear all
% Read image
imagen=imread('IMG_4367.JPG');
% Show image
subplot(3,2,1);
imshow(imagen);
title('原图');
title('INPUT IMAGE WITH NOISE')
% Convert to gray scale
if size(imagen,3)==3 %RGB image
imagen=rgb2gray(imagen);
end
[r,c]=size(imagen);
% Convert to BW
threshold = graythresh(imagen);
%**********************************************
sum=0;
for i=1:r
for j=1:c
if imagen(i,j)>threshold
sum=sum+1;
else
sum=sum-1;
end
end
end
%一般来说，车牌中，背景所占的比例大于前景所占的比例
if sum>=0 %sum大于0.说明背景的像素值偏大
imagen=im2bw(imagen,threshold);%将图像二值化 [0 threshold]设为1，[threshold
255]设为0. 背景设为黑色，前景设为白色
else
imagen =~im2bw(imagen,threshold); %将图像二值化 [0 threshold]设为0，[threshold
255]设为1.
end
% %图像形态学处理
SE=strel('arbitrary',[0 1 0;1 1 1;0 1 0]);
imagen=imerode(imagen,SE);
imagen=imdilate(imagen,SE);
%imagen =~im2bw(imagen,threshold); %将图像二值化
%**************************************************
% Remove all object containing fewer than 30 pixels
imagen = bwareaopen(imagen,30); %排除小于30像素的连通区域
subplot(3,2,2);
imshow(imagen);
title('二值化结果');
%Storage matrix word from image
word=[ ];
re=imagen;
%Opens text.txt as file for write
fid = fopen('text.txt', 'wt');
% Load templates
load templates
global templates
% Compute the number of letters in template file
num_letras=size(templates,2);
global num_letras;
%********************************************
%采用基于水平与垂直投影的字符分割方法
%计算垂直投影
clear sum;
vertical=sum(imagen,2);
subplot(3,2,3);
plot(vertical);
title('水平投影结果');
%根据垂直投影结果剪切图片
row=uint32(size(vertical,1)/8);
Y1=min(vertical(1:row,1));
r1=find(vertical(1:row,1)==Y1);
Y2=min(vertical(size(vertical,1)-row:size(vertical,1),1));
r2=find(vertical(size(vertical,1)-row:size(vertical,1),1)==Y2);
imagen=imagen(max(r1):size(vertical,1)-row+min(r2)-1,:);
subplot(3,2,4);
imshow(imagen);
title('剪切得到的结果');
%计算水平投影
Horizon=sum(imagen); %Horizon 记录了imagen的列和
subplot(3,2,5);
plot(Horizon);
title('垂直投影结果');
space=(size(Horizon,2)-0)/7;
i=5;
[L Ne] = bwlabel(Horizon);
figure;
count=1;
global count;
for n=1:Ne %Ne 标识连通区域的个数
[r,c] = find(L==n);
% Extract letter
n1=imagen(:,min(c):max(c));
if max(c)-min(c)>4*space/3
letters=[];
global letters;
letters=Csegmentation(n1,min(c),max(c),Horizon,space);
word=[word letters]
else if max(c)-min(c)>space/6
img_r=imresize(n1,[180 90]);
subplot(5,2,count);
imshow(img_r);
imwrite(img_r,strcat(num2str(count),'.bmp'));
count=count+1;
% img_r=imresize(n1,[42 24]); %将分割出来的字符进行归一化
% Call fcn to convert image to text
letter=read_letter(img_r,num_letras);
% Letter concatenation
word=[word letter];
end
end
end
%fprintf(fid,'%s\n',lower(word));%Write 'word' in text file (lower)
fprintf(fid,'%s\n',word);%Write 'word' in text file (upper)
% Clear 'word' variable
word=[ ];
fclose(fid);
%Open 'text.txt' file
winopen('text.txt')
clear all
仿真结果如下所示：
D180