Fluorescence Lifetime Imaging of Latent Fingerprints

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K20687
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 90110:Biomedical engineering-related
• Research Institution: National Research Institute of Police Science
• Principal Investigator: Kakuda Hidetoshi 科学警察研究所, 法科学第二部, 主任研究官 (80773936)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 光を用いた指紋の非破壊検出 / 紙上の潜在指紋の蛍光寿命イメージング

Outline of Final Research Achievements

Latent fingerprints were visualized by fluorescence lifetime imaging (FLIM). It was demonstrated that from a background paper whose fluorescence intensity was about four orders of magnitude larger than that of fingerprints, latent fingerprints were successfully visualized by FLIM. These fingerprints were not visualized by conventional methods such as using wavelength filters or time-resolved spectroscopy. The photoexcitation source was a nanosecond pulsed-laser with visible region. The reason for visualization of the latent fingerprints by FLIM was not given from a point of view of the fluorescence intensity. It was pointed out as a possibility that a certain interaction between the fingerprint and the background paper caused a detectable difference in fluorescence lifetime between them.

Free Research Field

生体医工学

Academic Significance and Societal Importance of the Research Achievements

光を用いた指紋の非破壊検出において、従来法では可視化できなかった指紋を、蛍光寿命イメージングにより可視化することに成功した。
光を用いた指紋の非破壊検出では、物体に付着した目に見えない指紋（潜在指紋）を光励起し、指紋が放出する蛍光を撮影することで、指紋を非接触に可視化する。従来の波長フィルタや時間分解分光法を用いて潜在指紋の可視化が困難な場合に、蛍光寿命イメージングを用いることでその指紋を可視化できる場合があることを示した。このことは、蛍光寿命イメージングが潜在指紋の可視化手法の新たな選択肢になりうることを示すものであり、法科学分野における指紋の非破壊可視化手法の拡大につながるものと考えられる。