how to do iris segmentation

please refer the image in the link

http://www.cl.cam.ac.uk/~jgd1000/iris_recognition.html

i used Daugman method to draw the circle around the iris..... but in my image the full circle is coming even if the full iris is not been seen.... but in the image in the link the circle is drawn only where the iris are present and the eyelids are also marked..... can anyone help me to draw the curve around the eyelid and the iris circle as in the link.....

Answer 1

[Image Analyst]

It looks like they also somehow found the upper and lower lid curves. To truncate the circles, it looks like you just need to know when the circle goes above or below the lid curve. Do you have the lid curve?

[Elysi Cochin]

no sir.... i dont have the lid curve.... i just got the circle around the iris....

[Image Analyst]

The how can you possibly know where to stop the circle? If you don't know where to stop, then you can't stop it.