draw circle for ROI in an image ?

Hello , I'm doing image processing in optical disc detection , i had database and i want to make a circle around the optical disc itself manually

how can i do that in order to make an mask and compare with it ?

Best regards

[Benjamin Drewry]

Try using viscircles https://www.mathworks.com/help/images/ref/viscircles.html

Answer 1

[Image Analyst]

Try imellipse(), or imfreehand() (demo attached).