Biometrics of the bottom

Researchers at Japan’s Advanced Institute of Industrial Technology have identified what they believe to be a new biometric signature – the pressure exerted by a person’s bottom when sitting on a chair.

The Japanese scientists have developed a pressure sheet with 360 sensors that collects 39 readings to uniquely identify a person. Dr Shigeomi Koshimizu led the research, but admitted that it isn’t quite ready for market:

The recognition tends to be compromised by different clothes. Sensors read different signals from a pair of trousers and a pair of jeans.

He is already quoting a 98% accurancy, though the scientists didn’t indicate whether they were suffering from a rate of 2% false-positives (i.e. 2 in 100 intruders would succeed in getting into the building) or 2% false-negatives (i.e. 2 in 100 genuine staff would be excluded from the building). Typically, biometrics seek a very low false positive (Type I) error rate, and worry less about false negative (Type II) rates.

To compare the “bottom-print” biometric with the more traditional fingerprint, analysis of fingerprints conducted by trained experts suffers from a false positive rate of 0.1% and a false negative of 7.5%, so bottom-printing requires some work yet before you’re likely to see it as an authentication mechanism to start your car.