what function do i use to remove large object ?

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?

Answer 1

[Image Analyst]

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.

[Shanxiong CHEN]

3Q~

[Image Analyst]

Shanxiong, what does "3Q~" mean? That's all you wrote, but I don't understand the comment.

Priyanka, you can also now use a function called bwareafilt().

[David Wang]

@Image Analyst, that just means thank you in chinese, if you're still wondering. When pronounced in chinese, it sounds like the words thank you

[Xihao Han]

@Image Analyst hahaha "3" in Chinese is pronounced like "than" while "Q" is like "k you"

[Image Analyst]

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.

Answer 2

[Walter Roberson]

bwareafilt()

Answer 3

[Romana Akhter]

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