MATLAB: Calculating centroids of multiple ROIs at a time

centroidimage processingroi

Hi,
I have segmented my ROIs, which are circles/ellipses. I need to calculate the centroids of all ROIs at a time and save those values in Excel file for further processing. I am not able to figure out how to do that.
I am attaching my segmented image with multiple ROIs.
Thanks in advance.

Best Answer

If you have the binarized image, just use regionprops.
inpict = imread('blobs.png');  % standard test image
S = regionprops(inpict,'centroid')
S = 28×1 struct array with fields:
    Centroid

vertcat(S.Centroid)
ans = 28×2
    7.2857    7.2857
    5.0102  130.9389
   28.0000   19.5263
   48.2878  111.2950
   38.0556   44.5556
   42.5345  246.2414
   51.7201  180.0177
   52.6038   31.5094
   35.5000   69.5000
   36.5000   65.5000
Note that I'm not using your image in this example. I don't want to deal with cropping all the padding off, and the size (and thus the coordinates) are probably altered now anyway. Don't save images by saving the displayed figure. There's rarely a good reason to degrade images by doing that. Just use imwrite().
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