With machines that produce images of the eyes in very high resolution and compare the information with a database. But the identification processes are different: the retinal reading analyzes the formation of blood vessels that irrigate the back of the eye, while the iris reading examines the colored rings and dots existing around the pupil. Because it is more complex, iris decoding is safer and used on a larger scale. Biometrics began to gain prominence in the early 19th century due to the use of physical traits in resolving legal cases. But all this precision is expensive: a retinal reader costs an average of R$8,000, and an iris reader, at least R$4,000.
eye on bid
The beginning of the process is different for iris and retina analysis – but in the end, it all turns to math
WRITTEN IN BLOOD
In the identification of the retina, the drawing of the blood vessels inside the eye is recorded. The individual must stand still and look, slightly widened, at the camera of the biometry machine, which emits, for about five seconds, a low-intensity pulsed white light
CONNECT THE DOTS
For the iris reading, which identifies points and rings in the colored band of the eyeball, the process takes just three seconds. The light (which can be infrared, so that the pupil dilates) makes a vertical movement over the eye. The common distance between the eye and the camera is between 7.5 and 25 cm
WHAT’S YOUR NUMBER?
The captured image gains a mathematical representation, decoded by an algorithm, so that the computer can compare it to the others in the file. Each type of biometry has one or more algorithms – there are two for the retina and five for the iris. They are all patented
FREE ACCESS
The system can cross the mathematical result with other data, such as the RG, to identify the individual among all those registered. Or just use this result to search for the person in the file. Advanced systems can scan 10 million records in just two seconds
• In addition to eyes and fingerprints, biometrics can be applied to the timbre of a person’s voice and even handwriting
Sources Ricardo Yagi, specialist in biometric technologies and director of the company ID-TECH, and websites The Biometrics Resource and The Biometric Consortium
– Why do we scratch our eyes when we’re sleepy?
– Why does the touch screen only recognize finger touches?