How the ThinkPad fingerprint reader works
Posted: Sun Oct 09, 2005 4:55 am
I've been curious about how the fingerprint reader on newer ThinkPads work, if anyone can help:
- Training makes you swipe each finger three times. Should you try to make them represent three different ways you might normally swipe that finger (with variations in angle/tilt -- or even speed, pressure, direction, etc), in the hope that the pattern stored will be the sum total of all the information? Or does the training only check that the three swipes are consistent enough from one to the next, but it might only store the pattern from one of the swipes (be it the first, second, or third)?
- I read somewhere that for training you should swipe your finger a lot slower, but you can swipe at normal speed thereafter?
- Does it matter how much pressure you apply (especially for training)? I was afraid too light might mean it won't read as much of the fingerprint ridge pattern, but too hard might make the ridges too smudged?
- What kind of sensor/technology is used? I recall there were several different technologies used in aftermarket USB fingerprint readers, with different strengths/weaknesses (some read deeper than the outer skin layer and aren't affected by smudge/grease or pressure, some only work with live flesh so that you can't use a dead cut-off finger, etc).
- Training makes you swipe each finger three times. Should you try to make them represent three different ways you might normally swipe that finger (with variations in angle/tilt -- or even speed, pressure, direction, etc), in the hope that the pattern stored will be the sum total of all the information? Or does the training only check that the three swipes are consistent enough from one to the next, but it might only store the pattern from one of the swipes (be it the first, second, or third)?
- I read somewhere that for training you should swipe your finger a lot slower, but you can swipe at normal speed thereafter?
- Does it matter how much pressure you apply (especially for training)? I was afraid too light might mean it won't read as much of the fingerprint ridge pattern, but too hard might make the ridges too smudged?
- What kind of sensor/technology is used? I recall there were several different technologies used in aftermarket USB fingerprint readers, with different strengths/weaknesses (some read deeper than the outer skin layer and aren't affected by smudge/grease or pressure, some only work with live flesh so that you can't use a dead cut-off finger, etc).