(Kanade; Jain; Ratha, 4, 12) Retina person can be identified from his retina by evaluating the picture of the blood vessels behind the eyes. These blood vessels are called choroidal vasculature. While taking the picture of the retina using infrared rays, the retina is not clearly seen. But certain equipments catch a glimpse of the visual spectrum that assists the evaluation of the retina. The exclusive model of the blood vessels is the identifying factor in a retina. (Bolle, 53) it is not the same even in the case of twins. (U.S. General Accounting Office (a), 27) EyeDentify equipments used to verify retina can check almost three thousand people. Verification of around 1500 people may be conducted in less than five seconds by this equipment. This equipment however cannot capture the image of individuals who has poor vision or severe astigmation. The person under question should be placed near the equipment to get a good picture. This is a costly method to identify retina in comparison to other method of biometric verification. An important aspect of identification through retina is the permanent condition of the retina unless it undergoes a change due to severe mishap. This is a reliable method because a person cannot fix an artificial retina into the eyes. Besides the use of EyeDentify equipment, recent inventions has lead to capture the retina using electromechanical feeler from a close point to learn about its reflective aspects as well as its absorption features. In this method, the retina is first exposed to a 7mW light which enhances the opportunities to know about the model of the veins. One of the disadvantages of the method is the huge price of the feeler. (Bolle, 53)

Another method used to get a picture of the retina is by passing light through the pupil of the eye. The model of the blood vessels is recorded at 400 spots to create a 96 byte model. Identification of a person through retina is employed in important security settings and government buildings. Biometrics using retina is one of the most difficult methods. Ancient techniques required individuals to look at a circling green light for about ten to twelve seconds at a distance of half an inch from the eyes and remain constant. But latest technology requires a person to stay constant only for about 1.5 seconds and the picture of retina can be capture at a distance of about one meter. This method is not sensitive to cataracts, sun glasses or contact lens. Hence it has an edge over the older method. Retina remains the same throughout life, but may undergo a change if a person undergoes glaucoma, high blood pressure, diabetes or AIDS. Though there are latest techniques to identify retina, certain individuals are reluctant to this method since they are exposed to infrared lights. Some people show reluctance since they feel this test would reveal symptoms of illness. Other than EyeDentify, Retinal Technologies is the enterprise which sells equipment to verify retina. (U.S. General Accounting Office (a), 27)

Voice

The identity of a person is cracked down from his voice and speech. The words in a person's speech are classified into several parts called phonemes. Phonemes are distinguished based on the cadence, inflection and its pitch. The voice of a person is interpreted out of these three aspects which are inherited from family, culture and the place of one's living. The accent of a person is influenced by his surroundings. The voice of a person has both behavioral as well as physiological relevance for biometric. Hence our voice...

An example is the voice of a child and the voice of an adult. Further a person's voice modulates according to the surroundings from where he speaks. This makes voice an important aspect to assess security through biometric. A voice can be recorded either through a telephone or through a computer. A voice recorded through microphone fixed to a computer gives a better quality record for interpretation. Necessary deletion of other voice in the surrounding can be done in this method. (Reid, 110-112)
Modern digital cellular techniques can also be applied to record voice. There are four steps to verify a voice to find identity. They are permanent phrase assessment, permanent vocabulary assessment, flexible vocabulary assessment, text independent assessment. In permanent phrase assessment, the phrase is repeatedly interpreted by using the cadence in the phoneme. When a similar wave is found in the model of the interpreting equipment, the identity of the voice is established. Permanent vocabulary assessment is done using the words repetitively used by the person. The words are translated into digits zero through nine. A repetition of the model created by these digits compared to the person results in finding the match. Flexible vocabulary assessment is conducted in a situation where the person uses a set of words in a given setting for verification. Here the words are compared to a combination of phonemes. While testing for verification the person uses these words and then they are evaluated to find identity. In text independent assessment many words are checked for identity. This is judged as a poor method of verifying voice. The best method of verification can be assessed depending on the level of security in a setting and the ease to handle it. (Reid, 114)

Conclusion

Certification of identity using biometric assessment is gaining momentum in offices and common places to ensure security. Besides, security it is the convenience factor that gives importance to biometric. The details of identity are encrypted to stop duplication in various public facilities. Biometric details are entered into equipment and the embedded software verifies for authentication. Thus, factors like face, iris, retina, voice and fingerprints in a human body which cannot be duplicated, forms the basis for biometric verification.