Vascular biometrics have a lot to offer

Hitachi finger vein scanner could secure large venues (Network World)

The scanner is able to confirm a person’s identity by detecting finger vein patterns, which are unique to each person. It works regardless of the number of fingers used or their orientation above the scanner surface, allowing it to process about 70 users per minute.

Vascular biometrics have a lot to offer. There's no latency (i.e. no prints left behind). They're contactless, and they're getting faster.