How to get all the x,y coordinates of inner boundary of an image?

I need to draw a polygon shape boundary over the image and access all the coordinate points inside the boundary-

Please help me to draw the arbitary shape boundry over an image and store all the coordinates of [x y] in a variable.

Thanks in advance.

Answer 1

[Image Analyst]

See my attached freehand drawing/masking demo.

[Mathews Jabaraj Soloman]

Thank you very much for your effort.

The freehand_drawing_demo.m saves the coordinate of the polygon line I draw but I wanted to get the coordinate inside the polygon boundary. But I have used the same code to extract the coordinates inside the boundary. I works finally..

[Image Analyst]

You can use poly2mask() and bwboundaries(). It will get the boundaries of any blobs, whether exterior or interior (holes of the donut).

[Mathews Jabaraj Soloman]

Yes, I will try that too

thanks again