How to extract second largest blob from image?

I have a binary image, and have extracted the largest and second largest images from a grayscale image (using bwareafilt). This gives me the image below:
How do i extract the image on the right (the second largest image)?
Using regionprops I have the Area, Centroid and Bounding Box for both blobs, but I am not sure how to use these values to extract the image on the right.
Thank you.

4 Comments

Sorry I solved it, dont know if i should delete or not but I did the following, BW is the binary image:
bwareafilt(BW, 2)-bwareafilt(BW, 1);
You can also use bwregionprops to find area of each blob
How would I remove the larger image knowing just the area?
Replace that region pixel values with black ones....

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Answers (1)

large_1=bwareafilt(binary_image,1); %Extracting Large Blob
large_2=binary_image & ~large_1; % Logical Operation to get 2nd largest Blob
large_2=bwareafilt(large_2,1); % Remove extra small blobs
imshow(large_2);

Asked:

on 16 Jun 2020

Edited:

on 18 Jun 2020

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