title: Portable hyperspectral imager with continuous wave green laser for identification and detection of untreated latent fingerprints on walls.
abstract: Untreated latent fingerprints are known to exhibit fluorescence under UV laser excitation. Previously, the hyperspectral imager (HSI) has been primarily evaluated in terms of its potential to enhance the sensitivity of latent fingerprint detection following treatment by conventional chemical methods in the forensic science field. In this study however, the potential usability of the HSI for the visualization and detection of untreated latent fingerprints by measuring their inherent fluorescence under continuous wave (CW) visible laser excitation was examined. Its potential to undertake spectral separation of overlapped fingerprints was also evaluated. The excitation wavelength dependence of fluorescent images was examined using an untreated palm print on a steel based wall, and it was found that green laser excitation is superior to blue and yellow lasers' excitation for the production of high contrast fluorescence images. In addition, a spectral separation method for overlapped fingerprints/palm prints on a plaster wall was proposed using new images converted by the division and subtraction of two single wavelength images constructed based on measured hyperspectral data (HSD). In practical tests, the relative isolation of two overlapped fingerprints/palm prints was successful in twelve out of seventeen cases. Only one fingerprint/palm print was extracted for an additional three cases. These results revealed that the feasibility of overlapped fingerprint/palm print spectral separation depends on the difference in the temporal degeneration of each fluorescence spectrum. The present results demonstrate that a combination of a portable HSI and CW green laser has considerable potential for the identification and detection of untreated latent fingerprints/palm prints on the walls under study, while the use of HSD makes it practically possible for doubly overlapped fingerprints/palm prints to be separated spectrally.
authors.affiliation: Waseda Research Institute for Science and Engineering, Waseda University, Shinjuku, Tokyo 169-8555, Japan. Electronic address: anakamura@waseda.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakamura
authors.affiliation: Waseda Research Institute for Science and Engineering, Waseda University, Shinjuku, Tokyo 169-8555, Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Okuda
authors.affiliation: Waseda Research Institute for Science and Engineering, Waseda University, Shinjuku, Tokyo 169-8555, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nagaoka
authors.affiliation: Second Department of Forensic Science, National Research Institute of Police Science, Kashiwa, Chiba 277-0882, Japan.
authors.forename: Norimitsu
authors.initials: N
authors.lastname: Akiba
authors.affiliation: Second Department of Forensic Science, National Research Institute of Police Science, Kashiwa, Chiba 277-0882, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kurosawa
authors.affiliation: Second Department of Forensic Science, National Research Institute of Police Science, Kashiwa, Chiba 277-0882, Japan.
authors.forename: Kenro
authors.initials: K
authors.lastname: Kuroki
authors.affiliation: JFE Techno-Research Corporation, Chuo, Chiba 260-0835, Japan.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Ichikawa
authors.affiliation: JFE Techno-Research Corporation, Chuo, Chiba 260-0835, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Torao
authors.affiliation: Waseda Research Institute for Science and Engineering, Waseda University, Shinjuku, Tokyo 169-8555, Japan; Department of Electrical Engineering and Bioscience, Waseda University, Shinjuku, Tokyo 169-8555, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sota
mesh_terms: D000328:Adult; D003878:Dermatoglyphics; D006801:Humans; D007834:Lasers; D008297:Male; D008875:Middle Aged; D013050:Spectrometry, Fluorescence
keywords: CW visible laser; Fluorescence; Hyperspectral imager; Untreated latent fingerprints/palm prints on walls