iris recognition is related to scanning eyes and authenticating similar to finger print authentication.we scan the top layer of the eye that is IRIS and authenticate the person.
IRIS RECOGNITION SYSTEM FOR AUTHENTICATION
Identification of a person to be himself has been a historical concern. The persons today get identified by their signatures, PIN, passwords. But with the increasing insecure environment, where a person does not know when his ID card, password or signature will be stolen, there is an increased need for providing an identification system that recognize a person based on attributes that are impossible to steal. The Iris with
its unique characteristics provides the errorless way of recognizing individuals.
The Iris recognition system uses a video based system to locate the Iris in the eye. The information of the Iris is then converted to the IrisCode, which then is compared with the stored IrisCode for the identification of the individual.
The unique nature of the Iris guarantee that the individual is recognized to be himself. No two persons have the same Iris structure,not even the same person’s two eyes have the same structure of iris.The recognition principle is the failure of a test of statistical independence on iris phase structure encoded by multi-scale quadrature wavelets.
The image of iris is captured with a black and white video camera in a well-lit environment. The pattern is extracted after elastic deformations are reversed mathematically,which is possible after localizing the inner and outer boundaries of iris. After pseudo polar coordinate mapping and using a method called complex valued 2D Gabor wavelets,a bit stream, typically total 256 bytes of information, is obtained. The amount and uniqueness of extracted information make the False Accept probability lowest of all known biometrics.
Reliable, automatic recognition of person has long been an attractive goal. In this discussion one of the most promising biometric technique called Iris recognition system is described. It is the most efficient of all the techniques used for biometric authentication.
Iris recognition system uses the Iris of the human to recognize him. Non-invasive, non-contact and extremely fast, high-resolution cameras are used to capture the image of the iris, translating it into an encrypted digital code, called IrisCode. This is stored into the database for future identification of the person. When the person needs to prove his identification, the same camera and process is used to build the IrisCode. The code previously stored in the database is then used to compare with the obtained code and the result is informed. The complete process of assessment may take not more than two seconds thus avoiding the wastage of time as is done in other techniques such as Fingerprint recognition system. This technology does not use the retinal scan technology and no laser is projected in the eye as in the retinal scan.
The False Acceptance Rate (FAR) and False Rejection Rate (FRR) of the Iris recognition system is very low compared to the other biometric recognition system such as fingerprint recognition system.
The Iris recognition system has advantages such as speed, accuracy, stability, non-invasiveness, and ability to do one-to-many matching, etc over the other identification technologies which makes it a much sought-after method for authentication of individuals.
Before discussing how the Iris recognition system works let us know about the Iris, which is used for recognizing the person.
The Iris is a protected internal organ of the eye, behind the cornea and the aqueous humor. It is the only internal organ of the human that is externally visible. Although small (11 mm) and sometimes problematic to image, the iris has the great mathematical advantage that its pattern variability among different persons is enormous such that no two persons have the same Iris pattern. Even the identical twins have different patterns As a planar object its image is relatively insensitive to angle of illumination, and changes in viewing angle cause only reversible affine transformations; even the non-affine pattern distortion caused by pupillary dilation is readily reversible. Finally, the ease of localizing eyes in faces, and the distinctive annular shape of the iris, facilitate reliable and precise isolation of this feature and the creation of a size-invariant representation. These features of iris give us the reason to use it for the identification of the individuals and once formed the Iris does not ever change.
This stability of Iris makes the Iris recognition system to be independent of the age. The iris pattern can easily be taken without any problem in dark or in lights. Also the iris is non-invasive, i.e. using of the spectacles or lens does not affect the performance of the system.
TECHNOLOGY BEHIND THE SCENES:
Iris recognition technology identifies humans by the unique physiological
patterns in the iris of the eye to a degree of accuracy surpassing even DNA matching.
Iris technology is based on pattern recognition and the pattern-capturing methodology based on video camera technology similar to that found in camcorders commonplace in consumer electronics. Like these cameras, the image capture process does not require bright illumination or close-up imaging.
The complete system can be divided into four important stages as
1. Finding an Iris in an image
2. Iris feature encoding with wavelength demodulation
3. Storing into database.
4. Test of statistical independence
FINDING IRIS IN AN IMAGE:
To capture the rich details of iris patterns, an imaging system should resolve a minimum of 50 pixels in iris radius. In the field trials to date, a resolved iris radius of 100
to 140 pixels has been more typical. Monochrome CCD cameras (480 x 640) will be been used because NIR (near infrared) illumination in the 700nm - 900nm band was required for imaging to be invisible to humans. Some imaging platforms deployed a wide-angle camera for coarse localization of eyes in faces, to steer the optics of a narrow-angle pan/tilt camera that acquired higher resolution images of eyes. Imaging can be done without active pan/tilt camera optics, by exploiting visual feedback via a mirror or video image to enable cooperating Subjects to position their own eyes within the field of view of a single narrow-angle camera.
Focus assessment will be performed in real-time (faster than video frame rate) by measuring the total high-frequency power in the 2D Fourier spectrum of each frame, and seeking to maximize this quantity either by moving an active lens or by providing audio feedback to Subjects to adjust their range appropriately. Images passing a minimum focus criterion will be then analyzed to find the iris, with precise localization of its boundaries using a coarse-to-.fine strategy terminating in single-pixel precision estimates of the center coordinates and radius of both the iris and the pupil. Once the coarse-to-fine iterative searches for both these boundaries have reached single pixel precision, then a similar approach to detecting curvilinear edges is used to localize both the upper and lower eyelid boundaries. The result of all these localization operations is the isolation of iris tissue from all other image regions, as illustrated in