How does iris scanning work?

To get past an iris-scanning system, the unique pattern of your eye has to be recognized so you can be positively identified. That means there have to be two distinct stages involved in iris-scanning: enrollment (the first time you use the system when it learns to recognize you) and verification/recognition (where you're checked on subsequent occasions).


First, all the people the system needs to know about having to have their eyes scanned. This one-off process is called enrollment. Each person stands in front of a camera and has their eyes digitally photographed with both ordinary light and invisible infrared (a type of light used in night vision systems that has a slightly longer wavelength than ordinary red light). In iris recognition, infrared helps to show up the unique features of darkly colored eyes that do not stand out clearly in ordinary light. These two digital photographs are then analyzed by a computer that removes unnecessary details (such as eyelashes) and identifies around 240 unique features (about five times more "points of comparison" as fingerprint systems use). These features, unique to every eye, are turned into a simple, 512-digit number called an IrisCode® that is stored, alongside your name and other details, in a computer database. The enrollment process is completely automatic and usually takes no more than a couple of minutes.


Once you're stored in the system, it's a simple matter to check your identity. You simply stand in front of another iris scanner and have your eye photographed again. The system quickly processes the image and extracts your IrisCode®, before comparing it against the hundreds, thousands, or millions stored in its database. If your code matches one of the stored ones, you're positively identified; if not, tough luck! It either means you're not known to the system or you're not whom you claim to be.

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Advantages Of Iris Recognition:-

The iris of the eye has been described as the ideal part of the human body for biometric identification for several reasons:

It is an internal organ that is well protected against damage and wear by a highly transparent and sensitive membrane (the cornea). This distinguishes it from fingerprints, which can be difficult to recognize after years of certain types of manual labor. The iris is mostly flat, and its geometric configuration is only controlled by two complementary muscles (the sphincter pupillae and dilator pupillae) that control the diameter of the pupil. This makes the iris shape far more predictable than, for instance, that of the face.
The iris has a fine texture that—like fingerprints—is determined randomly during embryonic gestation. Like the fingerprint, it is very hard (if not impossible) to prove that the iris is unique. However, there are so many factors that go into the formation of these textures (the iris and fingerprint) that the chance of false matches for either is extremely low. Even genetically identical individuals (and the left and right eyes of the same individual) have completely independent iris textures. An iris scan is similar to taking a photograph and can be performed from about 10 cm to a few meters away. There is no need for the person being identified to touch any equipment that has recently been touched by a stranger, thereby eliminating an objection that has been raised in some cultures against fingerprint scanners, where a finger has to touch a surface, or retinal scanning, where the eye must be brought very close to an eyepiece (like looking into a microscope).

The commercially deployed iris-recognition algorithm, John Daugman's IrisCode, has an unprecedented false match rate (better than 10−11 if a Hamming distance threshold of 0.26 is used, meaning that up to 26% of the bits in two IrisCodes are allowed to disagree due to imaging noise, reflections, etc., while still declaring them to be a match). While there are some medical and surgical procedures that can affect the color and overall shape of the iris, the fine texture remains remarkably stable over many decades. Some iris identifications have succeeded over a period of about 30 years.

Iris Recognition In Movies And Cinema :-

I Origins (2014), a Hollywood film by writer-director Mike Cahill and winner of the Alfred Sloan Award for best exposition of technology (2014 Sundance Film Festival), uses iris recognition for its core plot.

Culminating in India with the UIDAI project to encode and enroll the iris patterns of all 1.2 billion Indian citizens by the end of 2015, the film is described as a "science fiction love story incorporating spiritualism and reincarnation", seeking to reconcile science with religious spirit-world beliefs.

Steven Spielberg's 2002 science fiction film Minority Report depicts a society in which what appears to be a form of iris recognition has become a daily practice. The principal character undergoes an eye transplant in order to change his identity but continues to use his original eyes to gain access to restricted locations.

In The Island (2005), a clone character played by Ewan McGregor uses his eye to gain access through a security door in the home of his DNA donor.
The Simpsons Movie (2007) features a scene that illustrates the difficulty of image acquisition in iris recognition.

The TV series Numbers features a scene where a robber gets into the CalSci facility by cracking the code assigned to a specific iris.

NCIS uses an iris scanner in the garage, where forensic vehicle investigations are carried out and evidence is stored. There is another scanner at the entrance to MTAC. The sequence of Leroy Jethro Gibbs being verified is shown in the title sequence. The imagery for this sequence has been "enhanced" using special effects. Iris recognition systems do not use the laser-like beams shown in the sequence and the light that they do use is near-infrared and nearly invisible.

The 2010 film RED includes a scene where Bruce Willis' character uses a contact lens to pass an iris scan and gain access to CIA headquarters.

What makes an iris scan unique?

The iris is the colored ring of muscle that opens and shuts the pupil of the eye like a camera shutter. The colored pattern of our irises is determined genetically when we're in the womb but not fully formed until we're aged about two. It comes from a pigment called melanin—more melanin gives you browner eyes and less produces bluer eyes. Although we talk about people having "blue eyes," "green eyes," "brown eyes," or whatever, in reality, the color and pattern of people's eyes is extremely complex and completely unique: the patterns of one person's two eyes are quite different from each other and even genetically identical twins have different iris patterns.