Crop a specific area for the sem image
2 views (last 30 days)
Show older comments
luo jingcheng
on 27 Oct 2023
Answered: Image Analyst
on 27 Oct 2023
I have many images containing SEMs and annotations. I want to crop out just the SEM content, the black square regions, using Matlab. This requires Matlab to locate the black borders of the SEMs and record those coordinates, then use imcrop to crop the specific areas. I don't want the white content within the SEMs to affect the determination.
thanks!
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1522566/image.png)
2 Comments
KSSV
on 27 Oct 2023
Why don't you show us what areas you want from the image. You may highlite the regions using paint.
Accepted Answer
Akira Agata
on 27 Oct 2023
How about the following?
% Read the image
I = imread("https://www.mathworks.com/matlabcentral/answers/uploaded_files/1522566/image.png");
% Create ROI mask
Igray = rgb2gray(I);
BW = Igray>50;
BW = imclearborder(BW);
BW = bwareafilt(BW, [5000 Inf]); % Ignore small ROIs (<5000 pixel)
% Calculate bounding box for each ROI
s = regionprops("table", BW);
s = sortrows(s, "Area", "descend");
% Crop each region from the image
cImg = cell(height(s), 1);
for kk = 1:height(s)
cImg{kk} = imcrop(I, s.BoundingBox(kk, :));
end
% Visualize the result
figure
montage(cImg, "BackgroundColor", "w")
More Answers (1)
Image Analyst
on 27 Oct 2023
It's a generic, general purpose demo of how to threshold an image to find blobs, and then measure things about the blobs, and extract certain blobs based on their areas or diameters. Note how each of the coins in the demo image is cropped out to its own image. Just replace the image with yours. And you can use bwareafilt to get rid of small blobs, like the letters or other annotations in the image.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1523046/image.png)
0 Comments
See Also
Categories
Find more on Image Filtering and Enhancement in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!