Separation of Overlapping Fingerprints in Multilayered Carrier Using Optical Coherence Tomography
Fingerprints lifted from crime scenes are often overlapped because of multiple impressions of fingers. Current methods to separate overlapping fingerprints are primarily based on algorithms that estimate the orientation field of component prints. However, these methods need human intervention, and the accuracy of the separation may easily be degraded. In this paper, a novel tomographic imaging technique, optical coherence tomography (OCT), was used to separate overlapping fingerprints intuitively and noninvasively. The OCT system was also applied to reveal a hidden blood fingerprint that was completely covered by one layer of nontransparent paint. An additional experiment was conducted using a piece of fabric and fingerprints on tape to simulate a more realistic case work condition. OCT directly probed the internal features and extracted the images of component fingerprints deposited on multiple layers of material by three-dimensional volumetric imaging in a simple, intuitive, and easy-to-operate manner.