Fill the concave regions between two points in a Lung Image

I am working on lung segmentation. I want to fill the concave regions between two points. The points are called ‘critical points’. Problem is that sometimes there may be convex regions between two ‘critical points’. I want to fill only the concave regions (not the convex regions). How will I find the concave regions between two points? In the image, you can see that there are two 'openings'. I want to close the opening A but not the opening B.

[Image Analyst]

You forgot to attach any image. use the green and brown frame icon to insert your image.

http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[MUSTAFA]

Attached the image

 In the image, you can see that there are two 'openings'. I want to close the opening A but not the opening B.

Answer 1

[Cyrus]

Hi,

split your image into two sub-images(split it from middle).

then use morphological " imclose " function for the left part.

then merge the modified left side with untouched right half image.

"The morphological close operation is a dilation followed by an erosion, using the same structuring element for both operations".