On the face of it

Computer software developed at the University of Illinois can estimate a person's age by examining only their face.

'Age-estimation software is useful in applications where you don't need to specifically identify someone, such as a government employee, but would like to know their age,' said Thomas Huang, the William L Everitt distinguished professor of electrical and computer engineering at the university.

For example, age-recognition algorithms could stop underage drinkers from entering bars, prevent minors from purchasing tobacco products from vending machines and deny children access to adult websites, added Huang, who leads the Image Formation and Processing group at the university's Beckman Institute.

Estimating someone's age is not an easy task, even for a computer. That's partly because the aging process is determined not only by a person's genetic make-up, but by many other factors as well, including health, location and living conditions.

'Human faces do convey a significant amount of information, however, and provide important visual cues for estimating age,' Huang said. 'Facial attributes, such as expression, gender and ethnic origin, play a crucial role in our image analysis.'