olemus
ISO/IEC 19794:
kujutis, mis on hõivatud
sõrmeküüne kahe serva vahel asuvana,
tavaliselt saadakse vaaliva liigutusega
ühest küüneservast teiseni
= image captured that is located between the two edges of the fingernail
Note. This type of image is typically acquired using a rolling motion from one edge of the fingernail to the other.

piltlikult
https://www.youtube.com/watch?v=d7N-4UNAzsw

vt ka
- surutud sõrmejäljekujutis