remove wanted portions in binary image

i wanted to extract only the white portion from the image

i get more than one region... i should get only one region.... please do reply.....

Answer 1

[Image Analyst]

There is a function for removing blobs smaller than a specified size. It's called bwareaopen():

cleanedBinaryImage = bwareaopen(binaryImage, 40); % Remove blobs smaller than 40.

Alternatively you can use a function I wrote to keep, or eliminate, the N largest, or smallest (whichever you specify), blobs. See attached demo in blue text below. This is more general and flexible than bwareaopen, but more complicated.

[Elysi Cochin]

thank you so much sir for the reply... it helped me a lot.... thank u sir....

Answer 2

[Jeremy Wurbs]

If you wish to remove small regions from the binary image itself, you could start by looking at morphological operations ( help bwmorph), specifically erode and dilate.

You could also just remove the small regions from your bounding box list, or just take the largest one. I.e. only take bounding boxes where boundingBox(3)*boundingBox(4) >= minSize.

[Elysi Cochin]

thank u all for the answers....