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From: Jeff Liebermann <jeffl@cruzio.com>
Newsgroups: rec.bicycles.tech
Subject: Re: Artificiqal Intelligence
Date: Sat, 18 Jan 2025 20:34:07 -0800
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On Sat, 18 Jan 2025 20:01:44 GMT, cyclintom <cyclintom@yahoo.com>
wrote:

>A fingerprint scanner operates by cutting the fingerprint into segments and then attempting to match the same segment line for line. This involves shifting and rotating trying to find a match.

Close enough, I guess and not worth the time it would take me to
explain whey its not quite right.
<https://www.uscybersecurity.net/fingerprint-scanners/>
More:
<https://www.google.com/search?q=how%20to%20fingerprint%20scanners%20work>

>The initial scanners only tried to match the center of the finger print but now the CPU's are powerful enough that they can match the entire touchg zone and call it a match if they can achieve a 60% match.

Do some more reading before you try to reverse engineer how
fingerprint scanning pattern matching works:
<https://www.google.com/search?q=algorithm%20for%20fingerprint%20scanner%20pattern%20matching>
This might help:

Fingerprint Recognition
<https://ucr.fbi.gov/fingerprints_biometrics/biometric-center-of-excellence/files/fingerprint-recognition.pdf>
Pg 108:
"The scanning sequence and recorded data shall appear to have been
from left-to-right, progressing from top-to bottom of the fingerprint.
The origin of the axes, pixel location (0,0), is at the upper left
hand corner of each image with the x-coordinate (horizontal) position
increasing positively from the origin to the right side of the image
while the y-coordinate (vertical) position increasing positively from
the origin to the bottom of the image."

In fewer words, that means it scans from upper left to lower right.
This has been standardized for quite some time in order to facilitate
fingerprint data exchange between the various agencies.  There are
other scanning patterns that are used if the sensor is looking for
additional data, such as IR from tiny capillaries in the finger tips.

Incidentally, the batting average is far better than your 60%.
"Biometric Fingerprint Authentication Explained"
<https://www.descope.com/learn/post/fingerprint-authentication>
"The best system was accurate 98.6 percent of the time on
single-finger tests, 99.6 percent of the time on two-finger tests, and
99.9 percent of the time for tests involving four or more fingers.
These accuracies were obtained for a false positive rate of 0.01
percent."

Less than ideal scanners, such as those on cell phones and laptops
drop a few points in accuracy.  In general, no worse than 93% accuracy
for single finger authentication.  If you're going to invent numbers,
please make an effort to conjure something closer to reality.

So, have you washed your hands so that your Samsung phone fingerprint
scanner works more reliably?  Did you read Samsung's recommendations?
Did you wash your hands before using?

Note:  I can easily make the fingerprint scanner in my various phones
and laptops fail if I put my finger tips in any liquid or gas that
causes the fingertips to swell.  I was using alcohol to clean
something and had to use the phone.  The scanner failed repeatedly to
recognize me even after I washed my hands with water.  It took a few
hours for the scanner to recover.  If you're going to be drinking
ethanol, try not to splash it all over your fingers.



-- 
Jeff Liebermann                 jeffl@cruzio.com
PO Box 272      http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann      AE6KS    831-336-2558