How to extract the largest area?

Hi, I have a grayscale image as shown. How can I extract out the largest area? Thank you.

Answer 1

[Image Analyst]

It looks like there is a black path separating the different regions. I think you can just binarize the image and use bwareafilt

% Binarize the image
binaryImage = yourImage > 0;
% Make sure it's 2-D, not 3-D (which would be the case if yourImage was RGB).
if size(binaryImage, 3)) == 3
    binaryImage = binaryImage(:, :, 1);
end
binaryImage = bwareafilt(binaryImage, 1); % Take largest 8-connected region.

If you get multiple regions (because regions touch on a diagonal), then try using 4-connected:

binaryImage = bwareafilt(binaryImage, 1, 4); % Take largest 4-connected region.

[ZWY]

Yes, there are separated regions.

Thank you very much.