what function do i use to remove large object ?

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In matlab we use bwareaopen(I,n) function to remove object smaller than n pixel from image I.
Is there any function to remove object greater than m pixel from image I ?
what should i do to remove bigger object from image I?

Answers (3)

Image Analyst
Image Analyst on 2 Jun 2015
You can do it with bwareaopen():
bigBlobs = binaryImage - bwareaopen(binaryImage, n);
A nice versatile function for extracting the N largest or smallest blobs is contained in my attached demo.
  5 Comments
Xihao Han
Xihao Han on 2 Nov 2020
@Image Analyst hahaha "3" in Chinese is pronounced like "than" while "Q" is like "k you"
Image Analyst
Image Analyst on 2 Nov 2020
Thanks for the explanations on the cryptic Chinese textspeak.
Regarding the original question, since MATLAB Release R2014b there is a function called bwareafilt(), as the others have mentioned. Here is how you would use it to "remove object greater than m pixel from image I ?"
% Remove objects greater than m pixels in area from image I.
bigBlobs = bwareafilt(I, [1, m]); % Keep only blobs from 1 pixel to m pixels in area.
I really recommend you use more descriptive vatiable names. No one wants to look at an alphabet soup of a program with single letter variables, where it's not clear what they are. I'd recommend you not use I (eye) because it looks too much like 1 (one) and l (ell). I recommend you call it either binaryImage or mask. And instead of m, call it maxAllowableBlobSize. Then, someone reading that code will instantly know what the variables are.

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Walter Roberson
Walter Roberson on 27 Aug 2018
bwareafilt()

Romana Akhter
Romana Akhter on 18 Sep 2020
You can use bwareafilt(image, range). Here rang is the size of the objects you want to keep. See the link for details.
https://www.mathworks.com/help/images/ref/bwareafilt.html

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