extraction oval-like part from segmented image?

How to extract oval-like part in a vessel segmented image?

I want to extract the oval-like part in the middle of a segmented vessel image

image: https://copy.com/GT6n8EF82BKw)

I want to:

- compute the Distance Transform from black.

- Apply a Local Max to the Distance Transform.

- For each of those candidates, create a histogram of gradient angles. Try a 15x15 local

neighborhood, and a bin-size of 30 degrees (12 bins). Compute the standard deviation of the

histogram. the candidate with the lowest standard deviation would be the center of an aneurysm.

I have been stuck for long time,Could you please answer me or redirect my question to someone who can help.

Thank you in Advance

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If you some one know an active "Image Processing using MATLAB" groups, please add me

Answer 1

[Image Analyst]

Please define, outline, or somehow indicate the "oval-like part" that you'd like to extract or segment out.

[Nisreen Sulayman]

[Image Analyst]

I'd try an opening to detach the thing. Then I'd label the image and call regionprops. Ask for area, Euler number, and perimeter. Filter the results to get blobs that have an Euler number of 1 (meaning no holes) and a circularity of 3-5 or so (or smaller).

circularity = (perimeter .^2 )/ (4*pi*area)

You might also have to filter based on an area, like areas between 200 0and 2000 pixels or so. Measure everything and see what values your blob takes on and what the other blobs take on. Use ismember() to do the filtering if you want an image with only that blob in it.