Your veins are the key

Given that near infrared can penetrate a little way into skin, there are an increasing number of interesting applications that exploit that. I noted a medical system for locating veins last November.

Now a Swiss company is demonstrating a sensor that uses NIR to scan the pattern of veins on your wrist, which are apparently unique to you, to use as a biometric key. There's more on the BIOWATCH web site and also in a news item on the BBC web site.

After recent problems that Apple's watch infrared sensor found with tattoos, it'd be interesting to know whether they'd cause a problem for this sensor. Presumably unless there's total coverage, there will still be some vein pattern to use. I assume there's a patent and a quick search throws up some interesting examples, such as US 6799726 B2 from 2000, which uses near-field radio in a wrist-watch to access ski lifts, and WO 1988004153 A1 from 1987, which concerns biometric sensing. As this latter patent points out, often this requires a user to carry out a special action, such as looking into something or placing a hand on something. With the advent of sensors small enough to fit onto a wristwatch strap, the sensing can be genuinely unobtrusive.