|
In future applications of contactless acquisition techniques for latent fingerprints the automatic localization of
potential fingerprint traces in crime scenes is required. Our goal is to study the application of a camera-based
approach1 comparing with the performance of chromatic white light (CWL) techniques2 for the latent fingerprint
localization in coarse and the resulting acquisition using detailed scans. Furthermore, we briefly evaluate the suitability
of the camera-based acquisition for the detection of malicious fingerprint traces using an extended camera
setup in comparison to Kiltz et al.3 Our experimental setup includes a Canon EOS 550D4 digital single-lens
reflex (DSLR) camera and a FRT MicroProf2005 surface measurement device with CWL6002 sensor. We apply
at least two fingerprints to each surface in our test set with 8 different either smooth, textured and structured
surfaces to evaluate the detection performance of the two localization techniques using different pre-processing
and feature extraction techniques. Printed fingerprint patterns as reproducible but potentially malicious traces3
are additionally acquired and analyzed on foil and compact discs.
Our results indicate positive tendency towards a fast localization using the camera-based technique. All fingerprints
that are located using the CWL sensor are found using the camera. However,the disadvantage of the
camera-based technique is that the size of the region of interest for the detailed scan for each potential latent
fingerprint is usually slightly larger compared to the CWL-based localization. Furthermore, this technique does
not acquire 3D data and the resulting images are distorted due to the necessary angle between the camera and
the surface. When applying the camera-based approach, it is required to optimize the feature extraction and
classification. Furthermore, the required acquisition time for each potential fingerprint needs to be estimated to
determine the time-savings of the camera-based localization approach throughout the entire acquisition of traces.
The analysis of camera images of printed fingerprint patterns shows positive tendencies, too. However, only small
sections of the fingerprint are sharply acquirable within a single photo, large sections of the image are usually
blurred due to the depth of field of the camera lens.
|
