How to keep only solid white dots and eliminate dots that inside them is black in the attached image?

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Penny13 2018-11-5

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评论： Akira Agata 2018-11-7

Example.jpg

Hello, Is there any way that I could remove the dots which are black inside from the attached image to just keep the solid white dots in the image? Thanks

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Answer 1

Akira Agata 2018-11-6

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在 MATLAB Online 中打开

bwpropfilt function would be helpful for your task. The following is an example.

% Read the image
I = imread('Example.jpg');
% Binarize the image
BW = imbinarize(rgb2gray(I));
% Suppress light structures connected to image border
BW = imclearborder(BW);
% Filter out regions which has hole(s)
BW = bwpropfilt(BW,'EulerNumber',[1 1]);

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Penny13 2018-11-6

Example2.jpg

Thanks a lot for your answer. If you don't mind I will ask one last question. For every dot that I have in this image Example2.jpg, How could I draw a square with only having the centroid of the dot?

Akira Agata 2018-11-7

在 MATLAB Online 中打开

Please use the regionprops function to detect centroid and bounding box for each area. The following is an example.

% Read the image
I = imread('Example2.jpg');
% Binarize the image
BW = imbinarize(rgb2gray(I));
% Suppress light structures connected to image border
BW = imclearborder(BW);
% Filter out regions which has hole(s)
s = regionprops(BW,{'Centroid','BoundingBox'});
% Show the result
figure
imshow(BW)
hold on
for kk = 1:numel(s)
  scatter(s(kk).Centroid(1),s(kk).Centroid(2),'rx')
  rectangle('Position',s(kk).BoundingBox,'EdgeColor','y')
end