Primer on Iris Biometrics

Introduction

Reliable individual identity is needed to prevent loss of sensitive information, to protect individual property rights, and to control access to secure locations. Biometric recognition technology offers a highly reliable method for verifying identity by using the unique physical characteristics of people. Biometrics' chief advantage is that it is immune to loss, theft, forgetfulness, and reproduction. Examples of common biometrics include fingerprint, DNA, palm vein, face, retina, and iris.

Iris based biometrics focuses upon the iris. A human iris is the colored portion of the eye surrounding the pupil and having a diameter of about 11 mm (almost 1/2 inch). The iris is composed of muscles that control the size of the pupil, thereby acting as a diaphragm that determines the amount of light that enters into the eyeball. Iris recognition technology verifies identity by using the pattern formed by these muscles.

Technology Benefits

Iris recognition combines multiple benefits that does not exist in any other biometric:

  • Iris is among the most accurate biometrics due to the repeatable and rich data exhibited by the iris.

  • The fractal structure of the iris is unique for each eye (left and right) of each person, even among twins.

  • This structure of the iris is stable throughout adult life, providing a highly repeatable identification reference.

  • Capturing an iris image does not require physical contact, is not viewed as intrusive by the user, and does not have a crime-related association like fingerprints.

  • With proper analysis and template coding, the unique fractal structure exhibits nearly infinite degrees of freedom, allowing iris recognition to scale to extremely large populations.

Identification Process

Identifying a person using iris recognition requires a few steps:

  • Natural light often reflects off the iris, creating glare that can obstruct part of the view, so the capture process uses near infrared light for illumination. Near infrared is invisible to the human eye.

  • A properly tuned and focused camera takes a clear and detailed image of the iris. Because of the high level of detail required, most existing cameras must be close (around 20 cm or 8 inches) to a user to capture an image.

  • Software must analyze the image to determine the position of the iris, segment the iris into smaller pieces, and remove any segments obstructions by items such as eyelids and eyelashes.

  • Each segment undergoes complicated mathematical wave transforms that extract the "digital fingerprint" of the iris. This information is called the template.

  • The template of the recently captured image must now be compared against a database containing iris images with identity information. A match produces the correct identity of the person.

Conclusion

Iris biometrics is now considered one of the trilogy of the most important biometrics: Face, Fingerprint, and Iris. The US military is utilizing iris recognition to help prevent terrorism. Several nations around the world are in the process of creating National ID programs that will include all three of these biometrics. As a result, national borders will be more secure, financial fraud from stolen identities will be decreased, and national services will be provided to the correct individuals.