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Positioning

Positioning fingers

As a part of the capture process the taken images are scanned for fingerprints. The found fingerprints are proven in a quality comparison test to collect the best images. To attain good quality fingerprint images the engine provides warnings about finger positioning. User programs should show these warnings on their interface to advise repositioning of the fingers. Our devices are equipped with status leds for displaying the finger positioning indicators.

Currently the following warnings are signalled:

Programming positioning

The finger positioning signals are stored in the finger failure mask. Its value is reported in the Fingers captured event or can be acquired by reading the fg_fail_mask property. The FPS_FAILURE enumeration contains its error flag bits.

Testing the hang out and counting the fingers are essential parts of the capture process. The hang out fingers can have good quality but should not be stored as best ones. If the finger count is not the set number, it is hard to find out the correct finger positions; hence the fingers are not stored.

The hand swap test can be turned on/off with the finger/check_hand property. This test gives signal only when the four fingers of the scanned hand are present.

The upright position test can be turned on/off with the finger/check_upright property. Its value is the maximal angle of fingers in radians. A negative value turns off the test.


Generated  for Fingerprint Scanner
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