In some applications such as field stations, disaster situations or similar conditions, it is desirable to have a contactless,
rugged means to collect fingerprint information. The approach described in this paper enables acceleration of the
capture process by eliminating an otherwise system and finger cleanup procedure, minimizes the chance of the spread of
disease or contaminations, and uses an innovative optical system able to provide rolled equivalent fingerprint
information desirable for reliable 2D matching against existing databases. The approach described captures highresolution
fingerprints and 3D information simultaneously using a single camera. Liquid crystal polarization rotators
combined with birefringent elements provides the focus shift and a depth from focus algorithm extracts the 3D data. This
imaging technique does not involve any moving parts, thus reducing cost and complexity of the system as well as
increasing its robustness. Data collection is expected to take less than 100 milliseconds, capturing all four-finger images
simultaneously to avoid sequencing errors. This paper describes the various options considered for contactless
fingerprint capture, and why the particular approach was ultimately chosen.
This paper describes a real time, low cost part metrology method for capturing and extracting 3D part data using a
single camera and no moving elements. 3D capture in machine vision is typically done using stereo photogrammetry,
phase shifting using structured light, or autofocus mechanism for depth capture. These methods rely on expensive and
often slow components such as multiple cameras, specialized lighting, or motion components such as motors or
piezoelectric actuators. We demonstrated a method for 3D capture using only a single camera, birefringent lenses and
ultra-fast electronic polarization switches. Using multiple images acquired at different polarization states and thus
different focal distances, a high-resolution 3D point cloud of a test part was extracted with a good match to the ground
truth data. This paper will describe the operation of the method and discuss the practical limitations.
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