Iris Scanning

What is Iris Scanning?

A CCD digital camera is placed at the heart of the system. The image of iris of the people is taken by using visible or infrared light. By using near- infrared rays, the image of iris can be taken. The color of pupil is black. It helps to isolate iris and pupil and the computer can easily isolate the pupil and iris. The camera can automatically focused or by using an audible feedback system to position the person correctly. The distance between eye and scanner must be separated at a distance of 3 to 10 inches. The computer will locate the center of pupil, edge of pupil, iris, eyelids and eyelashes when the computer captures the image.

After these processes, the pattern of iris is analyzed and the iris pattern will be converted into code. It can be used for security applications because the pattern of iris is different for different people. i.e the iris pattern is unique. So it is used in biometric identification applications because the iris is visible and has a protective structure and cannot be changed. It will not change even after any surgery in eye. Blind people can also use this facility because they also have an iris pattern.  The iris has its own random patterns which is unique and stable. The iris is the colored ring of muscles. It opens and closes the pupil which is like a camera shutter. The iris patterns of two eyes are different. Even the twins have different iris patterns.

Two stages of Iris scan:-

• Enrollment
• Verification/recognition

Enrollment: - The eye is scanned first and this process is known as enrollment. At first, the person stands infront of the camera and takes a digital image of the iris by using both visible and infrared light. The two images are analyzed by the computer and mitigate the unwanted details. It is able to identify about 240 unique features. The features of the iris are converted into a 512 digital number which is called as iris code and it is stored in the computer database along with the person’s name. It is an easier process which can take the image within few seconds and it is an automatic process.

Verification/Recognition: - After storing the details in the computer, then it can be utilized for authentication or recognition purposes. For the identification purpose, the person must stand infront of any iris scanner and again take the digital photograph of iris. The image is processed by the system and converts the iris code and then comparing with the iris code it is stored in the computer database to check the person is correct or not.

Working Principle of Iris scan

First the person’s eye is scanned using a camera. The software used for image processing will isolate the iris of the person by using two circles. One circle is drawn in the inner boundary and other circle is drawn from its outer boundary. The circle at inner boundary is in between pupil and iris and the circle at the outer boundary is in between iris and sclera. It is easy to detect the inner boundary. Then the concentric circles and radial circles from the origin will also draw its image. It helps to analyze the figure easily. The iris is located and compared easily. The pupil constricts and dilates at various light conditions. These analysis patterns easily analyze the image. The image of iris consists of light and dark regions. This will be converted into digital form. i.e if the brightness in a specified area is greater than 1, then it is considered as 1. If the brightness of a specified area is less than 1, then it is considered as 0. After some mathematical calculations, it will create a unique code which is known as digital Iris Code. The eye will always generate the same code whether it is dilated or constricted.

Advantages of Iris Scanning

• Accuracy.
• Unique: - The pattern of iris is unique.
• Stable:-The iris is protected by a layer called cornea. The pattern is formed at 10 months of age and will never change in life time.
• Flexible: - Used along with the existing security systems.
• Reliable: - Cannot be reproduced or the pattern is not compromised or lost.
• Noninvasive: - It is quick and can be scanned without any contact. It is safe and hygienic because the scanning is taken with a particular distance.

Disadvantages of Iris Scanning

• Expensive due to high initial cost.