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Follow UsLike fingerprints, the retina and iris of the human eye exhibit uniqueness for each human. The retina is an internal part of the eye, while the iris is the outer colored part. The retina is located at the back of the eye, and is a set of thin nerves which senses the light coming through the cornea, pupil, eye lens and vitreous humor, in that order. The pattern of blood vessels which make up the retina are unique for each individual.
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The unique pattern of the blood vessels can recorded by a retina scan device. The individual whose retina pattern has to be scanned, must have his eye located at a distance of not more than a half inch. Also the position of the eye must not move while it is scanned. While scanning the individual looks at a rotating green light. For recognizing the patterns about 400 unique points on the blood vessels are recorded. For authentication, the recorded pattern is compared against the blood vessel pattern of the individual. If they match, access denied else prohibited.
| Your Speech is My Command |
| Speech-recognition software is perhaps the most commonly used biometric application. Using the software, you can tell your computer what to do, such as write a letter, open/close applications, or even login. It functions as a pipeline that converts digital audio signals coming from the sound card to recognized speech. These signals pass through several stages where various mathematical and statistical methods are applied to figure out what they mean. Several full-blown speech-recognition applications are available, the prominent ones being IBM’s ViaVoice and Dragon Naturally Speaking. For more on how speech recognition works and various software reviews, go to pcquest.com and search for ‘speech recognition’. |
Since the retina is an internal portion of the eye, retina scanning is considered intrusive. Thus the individual may be hesitant to get exposed to the scanning. Moreover, retina scanning is a costly and sophisticated process.
The iris has colored streaks and lines that radiate out from the pupil of the eye. The iris provides the most comprehensive biometric data after DNA. And the chances that any two people may have the same pattern is one in 10 to-the-power-78, which is way above the current population of the Earth. In this scanning, the characteristics of the iris are taken into account. About 266 unique points (compared to 40 in finger prints) are recorded and converted into a 512 byte IrisCode (somewhat similar to barcode). For recording the iris pattern, a monochrome camera is used and the distance between the eye and the camera can be at most 3 feet. The patterns located at the inner edge–at the pupil–of the Iris is recorded. The IrisCode constructed contains information the the characteristics and position of the unique
points.
Iris scanning can be done at day or night, with glasses or contact lenses on. Since iris scanning can be done from up to 2 feet away, it is not considered intrusive.
Shekhar Govindarajan