  We open source an easy to assemble, spoof resistant, high resolution, optical
fingerprint reader, called RaspiReader, using ubiquitous components. By using
our open source STL files and software, RaspiReader can be built in under one
hour for only US $175. As such, RaspiReader provides the fingerprint research
community a seamless and simple method for quickly prototyping new ideas
involving fingerprint reader hardware. In particular, we posit that this open
source fingerprint reader will facilitate the exploration of novel fingerprint
spoof detection techniques involving both hardware and software. We demonstrate
one such spoof detection technique by specially customizing RaspiReader with
two cameras for fingerprint image acquisition. One camera provides high
contrast, frustrated total internal reflection (FTIR) fingerprint images, and
the other outputs direct images of the finger in contact with the platen. Using
both of these image streams, we extract complementary information which, when
fused together and used for spoof detection, results in marked performance
improvement over previous methods relying only on grayscale FTIR images
provided by COTS optical readers. Finally, fingerprint matching experiments
between images acquired from the FTIR output of RaspiReader and images acquired
from a COTS reader verify the interoperability of the RaspiReader with existing
COTS optical readers.
