I believe NIST published something about FBI needing 40 minutia standard for registration in their database.
On tv you see these things about lifting partial prints and then sending them off to FBI to try and find who the partial print matches with, aka the FBI better have rather detailed recording of whatever part of the print that happened to be lifted. That is significantly different than trying to repeat scans in the same way, on nearly identical surface, from the same angle, of a "full" print etc. and approx. match at least a minimum number of points. By comparison, the fbi might need to have higher number of point match based on only a very specific subarea. That would imply that the needed resolution of valid points on the minimum acceptable sized subarea equivalent to typical matching of a full fingerprint. lets say that FBI wants to do acceptable minutia match on a 15 percent finger subarea (pure conjecture on my part, i've never even read anything about minimum resolution needed in partial print search) ... then presumably the (fbi's) total finger resolution (recording) might need to be six times higher than a straight-foward comparison involving always matching a full-finger to the same full-finger recording using essentially the same methodology each time. Even at that, the straight-forward fingerprint match (as opposed to the partial print search problem) is frequently subject to greasy & dirty finger problems. [EMAIL PROTECTED] at 1/28/2002 1:46 pm wrote: Last week I had to go to my local INS office to get fingerprinted (part of the green card process is getting your fingerprints OK'ed by the FBI (and also presumably stored for future reference)). The process is computerised, with a low-res scan of all the fingers taken once, and then each finger is individually rolled and scanned on a much higher resolution scanner. The process took about 20-30 minutes; each finger had to be wiped with some cleaning fluid, the glass on top of the scanner also had to be wiped between scans, and a fingerprinting technician had to roll each of my fingers with the right amount of pressure to get a clear image of the fingerprint. Even with immediate feedback on a large screen showing the fingerprint and how good the scan was, some fingers took as many as five tries to get an acceptable fingerprint. Now, this was a special-built device whose only purpose is to scan fingerprints, operated under ideal conditions by a trained technician. Draw your own conclusions about the effectiveness of mass-produced fingerprint scanners that would be integrated in other devices. /ji -- /\ ASCII ribbon | John "JI" Ioannidis * Secure Systems Research Department \/ campaign | AT&T Labs - Research * Florham Park, NJ 07932 * USA /\ against | "Intellectuals trying to out-intellectual / \ HTML email. | other intellectuals" (Fritz the Cat) --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED] --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]
