Hello mana111,
It is definitely possible to complete this application using IMAQ Vision. You may want to investigate using Vision Assistant and the Vision Development Module to prototype your application. This will allow you to setup the basic image processing and then export your algorithm to Labview for further development.
In order to create a successful algorithm, you will need to know about the features that characterize a person's iris. After you develop the vision algorithm to extract these features, you can begin development of the classification system.
Let us know how it goes - it sounds like a neat project!
Robert
