how to draw a rectangle to identify character
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This code to draw a rectangle to identify character that I had found (overlay the template in a target).
[name,path] = uigetfile('*.jpg');
image1 = imread([path,name]);
[name,path] = uigetfile('*.jpg');
image2 = imread([path,name]);
if size(image1,3)==3
image1=rgb2gray(image1);
end
if size(image2,3)==3
image2=rgb2gray(image2);
end
% check which one is target and which one is template using their size
if size(image1)>size(image2)
Target=image1;
Template=image2;
else
Target=image2;
Template=image1;
end
% find both images sizes
[r1,c1]=size(Target);
[r2,c2]=size(Template);
% mean of the template
image22=Template-mean(mean(Template));
%corrolate both images
corrMat=[];
for i=1:(r1-r2+1)
for j=1:(c1-c2+1)
Nimage=Target(i:i+r2-1,j:j+c2-1);
Nimage=Nimage-mean(mean(Nimage)); % mean of image part under mask
corr=sum(sum(Nimage.*image22));
corrMat(i,j)=corr;
end
end
回答（3 个）
Image Analyst
2014-3-29
0 个投票
That's a dangerous way to use size(). Looks like someone needs to read Steve's blog on the use of the size function.
Anyway, I'm not sure what your question is. Do you want to draw a rectangle in the overlay above the image? If so, use plot() or rectangle().
2 个评论
Image Analyst
2014-3-29
编辑：Image Analyst
2014-3-29
Anyway, you can't find a template in a target by correlation, at least not robustly. Think about it and if you don't know why, ask. You'll need to use normalized cross correlation, as shown in my attached demo.
raha boolat
2021-7-14
It was a wonderful program. Bravo
i want to draw a rectangle in a overlay the full image illuster to identify the character
1 个评论
Image Analyst
2014-3-30
Invert your image so that the letters are white and then run the normalized cross correlation code I gave you.
raha boolat
2021-7-14
编辑：Rik
2021-7-14
function obj_det(img_name)
f=imread (img_name);
if (size(f,3) >1)
f=rgb2gray(f);
f_bw=~im2bw(f,graythresh(f));
else
f_bw=~im2bw(f,graythresh(f));
end
f_bw=imfill(f_bw,'holes');
s=bwconncomp(f_bw);
imshow(f);
for i=1:s.NumObjects
ind=s.PixelIdxList{i};
[r,c]=ind2sub(size(f),ind);
min_r=min(r,[],1);
max_r=max(r,[],1);
min_c=min(c,[],1);
max_c=max(c,[],1);
hy=max_r - min_r;
hx=max_c - min_c;
rectangle('position',[min_c,min_r,hx,hy],'EdgeColor','r');
end
end
1 个评论
Rik
2021-7-14
@raha boolat This time I edited your answer for you. Next time, please use the tools explained on this page to make your posts more readable.
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