Detect all the rectangles in image
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Hey all,
in the following image, all the rectangles are a little bit deformed due to power leakage effect. I want to detect all the rectangles and obtain the positions of the rectangles.
Is there a way to detect all rectangles?
Thank you
采纳的回答
Image Analyst
2019-2-18
1 个投票
It's trivial. Just use regionprops(). See my Image Segmentation Tutorial
9 个评论
simon xu
2019-2-19
Image Analyst
2019-2-19
regionprops() gives you [xLeft, yTop, width, height]. From that you can get row1 (y1), row2 (y2), col1 (x1), and col2 (x2), as well as the centroid (xLeft + width/2, yTop + height/2).
You can also get a lot of other things from regionprops().
simon xu
2019-2-19
Thanks.
I'm wondering whether there is a useful method to remove the 'tails' (caused by power leakage effect) of the rectangles, illustrated in the following image
A naive way may be graythresh(), but it may be not satisfying, the following image is a binary image after thresholding
As a result, the rectangles which we detected may be not perfect, as shown below
So, if there is a more powerful method (more powerful than graythresh()) to remove these 'tails' of the rectangles, the detected shape would be more satisfying.
Is there a more powerful method?
Thank Image Analyst very much again!
KSSV
2019-2-19
Thanks is accepting the answer.
Image Analyst
2019-2-19
You can try imopen().
The following image is the original image
imopen() is helpful to smooth the boundaries and get rid of the 'tails' of these rectangles, as shown below. The following image is the image after imopen()
There are no notable 'tails', and then I use imadjust() to adjust the contrast, and then I use graythresh() and im2bw() to binarize the image and obtain the following binary image.
The top-right rectangle is missing after graythresh(). So, is there a better way of thresholding and binarizing to aviod missing any rectangle?
Thanks a lot!
% here is my code
MainImg = imread('originalImg.jpeg');
se = strel('rectangle',[4,5]);
openImg = imopen(MainImg,se);
enhenImg=imadjust(openImg);
BinImg = im2bw(enhenImg,graythresh(enhenImg));
Image Analyst
2019-2-20
How about you just compute the centroid, even with the tails, then take a vertical and horizontal line through the centroid and use find() to find the top and bottom lines and left and right columns of the rectangle?
simon xu
2019-2-22
更多回答（1 个）
KSSV
2019-2-18
I = imread('myImage.jpeg') ;
[y,x] = find(I>50) ;
imshow(I)
hold on
idx = kmeans([x y],4) ;
for i = 1:4
plot(x(idx==i),y(idx==i),'.')
% GEt L and B of rectangles
x0 = min(x(idx==i)) ; x1 = max(x(idx==i)) ;
y0 = min(y(idx==i)) ; y1 = max(y(idx==i)) ;
%
L = x1-x0 ;
B = y1-y0 ;
coor = [x0 y0 ; x0 y1 ; x1 y1 ; x1 y0] ;
patch(coor(:,1),coor(:,2),rand(1,3))
end
3 个评论
simon xu
2019-2-18
islam elsayed
2020-6-11
can you please explain in brief
islam elsayed
2020-6-11
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