Abstract: Biometric systems have been researched intensively by many organization and institution. It overcomes the conventional security systems by identify “who you are”. This paper discusses the current image based biometric systems. It first gives some information about why biometric is needed and what should people look for in biometric systems. Several popular image based biometric systems have been examined in this paper. The biometric systems included are face, fingerprint, hand geometry, hand vein, iris, retina and signature. Biometrics is associated with the use of unique physiological characteristics to identify an individual. The application associate with biometrics is security. Biometrics identifies an individual by measuring their physical and behavioural uniqueness or patterns, and comparing it to those on records. Iris recognition is the most unique and effective one which provides maximum security. When the case of wearing a contact lens comes then the fault mismatch chances are high. Even if the person is true the presence of contact lens makes a mismatch in the person’s identification. For the proper identification there exist two sets of databases and they are IIIT-D database and ND-Contact Lens database. These two databases perform very well when compared with the other lens detection algorithms.

Keywords: Biometrics, Iris Recognition, Segmentation, Normalization.