point of intersection of a circle and binary image

i have a binary image and i have plot a circle on it as shown in figure A.The circle intersects the image at 4 points.But i want to mark two point with cross marker similar to figure B .How do i do that. Plz help

Answer 1

[Doug Hull]

I have an ugly solution that might be what you want:

• run EDGE on the binary image. You now have a binary image with the edges.
• create a binary image with your circle being the TRUEs. Depending on how you specified your circle, this should be a very reasonable task.
• AND these two binaries together. You should find the points of intersection. You might need to clean them up a bit is all.