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
Antworten (3)
Image Analyst
am 29 Mär. 2014
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 Kommentare
Image Analyst
am 29 Mär. 2014
Bearbeitet: Image Analyst
am 29 Mär. 2014
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.
ahmed
am 29 Mär. 2014
Bearbeitet: ahmed
am 29 Mär. 2014
1 Kommentar
Image Analyst
am 30 Mär. 2014
Invert your image so that the letters are white and then run the normalized cross correlation code I gave you.
raha boolat
am 14 Jul. 2021
Bearbeitet: Rik
am 14 Jul. 2021
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 Kommentar
Rik
am 14 Jul. 2021
@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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