Biometrics has become an emerging technology thanks to its security feature regarding the identification of individuals by means of metric measurement of human characteristics. Biometrics is often categorized into physiological and behavioral characteristics. Physiological characteristics are related to the shape of the body such as: fingerprint, iris, palm, veins, face, etc. Behavioral characteristics are related to the pattern of behavior of a person like typing rhythm, gait, voice, etc. Based on those modalities, many important applications have been developed to serve the government and commercial purposes such as: national ID, border control, banking, m-payment, etc.
One of the most promising biometric modalities is iris recognition due to its accuracy and stability. Except for DNA, iris recognition is the most accurate method of biometric recognition. Iris is a flat, ring-shaped tissue behind the cornea of the eye and its color defines the eye color. Iris contains complex random patterns which are unique, stable, and can be seen from some distances. Iris recognition is an automated method to capture iris images at a comfortable distance that uses video camera technology with near infrared (NIR) illumination LED, not laser light which is usually confused with. The process only takes up maximum 3 seconds. Since iris scanners are being installed in many applications such as mobile, laptop, time & attendance device, etc., there is a growing concern about the possible use of LED illumination that might pose a potential threat to the human eye.
LEDs have been broadly deployed during the past 20 years due to their efficiency and low operating costs. In order to guarantee that ultraviolet (UV) and infrared (IR) light output from LED device do not exceed safety levels, products containing LED lights around the world required to be tested and certified. The standard requires that all LED and luminaries must have their output tested and recorded from 200-3000 nm by a certified laboratory to prove that the light does not exceed safety output thresholds defined by a certain luminosity at a given distance. Accordingly, iris devices that use NIR LED with wavelength from 700 – 900 nm to capture iris image is completely safe for human eye. The amount of this light is no more than one that would be received by walking outside on a sunny day. However, testing and documentation are required when it comes to safety issue for users all over the world.
Currently, there are 3 optical safety standards which are addressed by international guidelines including:
- CIE S009-2002: Photobiological Safety of Lamps and Lamp Systems
- ANSI/IES RP27: Recommended Practice for Photobiological Safety for Lamps and Lamp Systems
- IEC/EN 62471: Photobiological Safety of Lamps and Luminaires
Today, Europe, Canada, and parts of Asia require that all lights to be tested and documented to the IEC62471 standard. Additionally, in the US, American Conference of Governmental Industrial Hygienists (ACGIH) also established the Threshold Limit Values (TLVs) for chemical substances and physical agents and Biological Exposure Indices (BEIs) which is usually used as a safety reference in many test reports.
There have been numerous tests and reports that were conducted to set standards and guidelines for LED light which causes major safety concerns for users when facing iris scanner. It’s obviously shown that NIR is non-intrusive and totally safe. And the fact that iris recognition technology has been widely used by many governments around the world such as: the US, India, Canada, the UK, etc. and NGOs like United Nations High Commissioner for Refugees (UNHCR) or in many other commercial projects. Nonetheless, it is highly recommended that the iris scanner provider have the mentioned international certificate, and tested by certified laboratory. Just a little note for anyone who is still confused iris recognition with retinal recognition, please check out our previous blog article Retina vs. Iris Recognition: Similarities and Differences