How to reduce perimeter of Image in Matlab?

Hi,

I want to erode (Reduce the perimeter) of the below image by 7 pixels such that only the image within the red circle is kept.

I thought this could be done with imerode, but this also reduces the central pixels which I do not want!

Thank You :)

Answer 1

[Image Analyst]

Try this:

se = strel('disk', 7, 0);
binaryImage = grayImage > 0; % Threshold.
mask = imerode(binaryImage, se);
grayImage(~mask) = 0;

[Harry Andrews]

Amazing, thank you!!!