How to remove the edge of this medical image?

In the figure below,I need that tumor part separately,how can I remove the edge of this images using MATLAB with out affecting the tumor part.I tried my best to remove this,but failed at the end.Please help me to sort this problem.

Answer 1

[Massimo Zanetti]

The morphological operation imerode() suits your needs. I give you some hints, look at this plot after image erosion with an element of size 5 (which is approx the thickness of the line you want to remove):

A=rgb2gray(imread('Final Output.png'));
B=imerode(A,ones(5))
imagesc(B);

Thus, you can identify all connected components in the original image, and also in the eroded one. Then, the conn comp found in the original image that have large interseection with the ones in the eroded image can be stored.

[Suba Suba]

Thank you so much. It's working fine and how did you identify the size of element as 5(approximate size of the line),I'm new to MATLAB,Can you please explain me?

[Massimo Zanetti]

I have manually inspected your image, and I have noticed that the thick line to remove had 5-pixels width, approximately.

[Suba Suba]

oh okey.Thank you