Sir/madam, Can any one please suggest an appropriate code to fit circle over iris image?

we are working on a project related to iris recognition. we are segmenting the image using canny edge detector instead of using the circular hough transform. we have got the circle which indicates the iris outer boundary.the basepaper tells that we have to fit this circle over the original image and thus remove the portion outside this circle.Can any one please suggest an appropriate code to do this?

Answer 1

[Image Analyst]

See my circle masking code, attached.

[Sabira vattaparambil]

thank you Sir/madam, i was able to localize the iris portion using the above code. but, as i told it is given in the base paper that iris localisation is done using canny edge detection.the above code does not acquire any data from the edge detected output of the iris image.Can you please help me to sought out this?

[Image Analyst]

It does not acquire any data, you're right. You said "we have got the circle" so I assumed that you already have code where you got the circle (like you said). Then I gave you code to "remove the portion outside this circle" which is what you asked. Did you really mean to say other things than what you did? Are you using a successful, published algorithm like one of those found in Section 21.5.3 in VisionBib or are you trying to ignore all those and start from scratch?

Have you tried imfindcircle()? Have you looked at other messages here with the tag iris?

[Sabira vattaparambil]

we applied canny edge detection to a gaussian filtered iris image. By this we got the outer edge of the iris which is nothing but a circle.Now we need to fit this circle over the original iris image so as to remove the sclera part.we have to make use of the data acquired from the edge detection since the main objective of our project is to use canny edge detection in segmenting the image rather than going for circular hough transform, which is complex and consumes more time and memory.

[Image Analyst]

What do you mean "fit"? Is it not aligned? It should be. Have you gotten the circle lines extracted from all the other lines that Canny will produce? Is the circle closed? Usually when people ask advice on image processing they supply an image so people can see what they're talking about. Use the image icon above the edit box when you reply.

[Sabira vattaparambil]

from the circle obtained is there any code to calculate its radius and centre?

[Sabira vattaparambil]

</matlabcentral/answers/uploaded_files/11548/Canny.PNG> Sir/madam, This is the canny edge detected output which we have got. From the circle obtained is there any matlab code to find its radius and centre?

[Image Analyst]

See the FAQ: http://matlab.wikia.com/wiki/FAQ#How_can_I_fit_a_circle_to_a_set_of_XY_data.3F

I think that answers your question.

[Sabira vattaparambil]

Thank you sir/madam.