How to morphologically open a binary image ?
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Hello , i am trying to morphologically open(to decrease the retrieved area) a binary image . However i am getting a black image (all pixels are 0) .What is wrong ?
se=strel('disk',3);
Im_open=imopen(original_binary,se);
figure;
imshow(Im_open);
1 个评论
KALYAN ACHARJYA
2020-11-21
Please attach original_binary image.
回答（2 个）
Image Analyst
2020-11-21
This works just fine:
grayImage = imread('moon.tif');
subplot(2, 2, 1);
imshow(grayImage);
title('Original Gray Scale Image', 'FontSize', 15);
original_binary = imbinarize(grayImage);
subplot(2, 2, 2);
imshow(original_binary);
title('Binarized Image', 'FontSize', 15);
se=strel('disk',3, 0);
Im_open=imopen(original_binary,se);
subplot(2, 2, 3:4);
imshow(Im_open);
title('Opened Image', 'FontSize', 15);
If it doesn't for you then it's possible all your white blobs in your original image are less than 7 pixels in diameter (3 in radius). Or else your image is so big that the small things just get subsampled away for display (zoom in, in that case to see them).
6 个评论
Gn Gnk
2020-11-22
Gn Gnk
2020-11-22
Image Analyst
2020-11-22
Then don't call imopen() of course. What imopen() does is an erosion of the given radius, followed by a dilation of the given radius. But after the erosion, all your blobs are gone. There is nothing left to dilate. What made you think you should do an opening anyway? Did someone tell you to do that?
In my experience, the usual use of imopen() is to get rid of little tendrils and spurious/random hairs that are sticking out of a blob. You certainly don't have that if all your blobs are so tiny that they're only a few pixels big.
Gn Gnk
2020-11-22
Image Analyst
2020-11-23
OK, but then what that will do is to remove any blobs smaller than 3 pixels in radius, or 7 pixels in diameter.
Gn Gnk
2020-11-24
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