Separation of overlapping fingerprints by principal component analysis and multivariate curve resolution–alternating least squares analysis of hyperspectral imaging data

Abstract

Overlapping fingerprints are often found at crime scenes, but only individual fingerprints separated from each other are admissible as evidence in court. Fingerprint components differ slightly among individuals, and thus their fluorescence spectra also differ from each other. Therefore, the separation of overlapping fingerprints using the difference of the fluorescence spectrum was performed with a hyperspectral imager. Hyperspectral data (HSD) of overlapping fingerprints were recorded under UV LED excitation. Principal component analysis (PCA) and multivariate curve resolution—alternating least squares (MCR–ALS) were applied to the HSD to determine the optimal method for obtaining high‐contrast images of individual fingerprints. The results suggested that MCR–ALS combined with PCA‐based initialization is capable of separating overlapping fingerprints into individual fingerprints. In this study, a method for separating overlapping fingerprints without initial parameters was proposed.

Innovative Vibrational Spectroscopy Research for Forensic Application

“…For example, using fluorescence spectroscopy and HIS, Akiba et al developed a method of separating overlapped fingerprints. 263 In cases where two sets of FMs exist on top of one another, it is usually impossible to distinguish between them. However, measuring the fluorescence spectra of the FMs provided insight into the differences among these similar spectra.…”

“…Spectroscopic techniques are also being utilized to solve unique challenges in FM analysis. For example, using fluorescence spectroscopy and HIS, Akiba et al developed a method of separating overlapped fingerprints . In cases where two sets of FMs exist on top of one another, it is usually impossible to distinguish between them.…”

Interpol review of fingermarks and other body impressions (2019 – 2022)

“…Optical methods – Preliminary/Pilot studies – A couple of optical methods were proposed to detect latent fingermarks: UV-induced luminescence HSI combined with chemometric tools to separate overlapped fingermarks left on TLC plates [ 206 ]; reflected UV polarization imaging to detect fingermarks on flat, non-porous substrates [ 207 ]; short-wave 266 nm UV laser to induce long-wave UV luminescence of fingermarks on porous substrates [ 208 , 209 ] – note: the authors observed some laser-induced degradation of the fingermarks and the substrates; reflected MWIR imaging to detect fingermarks on the adhesive-side of tapes, and on flat, non-porous substrates [ 210 ]; OCT to separate “overlapped” or hidden fingermarks [ 211 ] – note: the so-called “overlapped” fingermarks were actually left on four stacked glass slides.…”

A Fast Density Peak Clustering Method for Power Data Security Detection Based on Local Outlier Factors

“…The principal components of the standardized matrix are calculated to obtain the principal component matrix, as shown in Formula (15) [26].…”