Saitoh Naoki, Akiba Norimitsu
Second Forensic Science Division, National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882 Japan.
ScientificWorldJournal. 2006 Jun 21;6:691-9. doi: 10.1100/tsw.2006.143.
We studied fluorescence imaging of fingerprints on a high-grade white paper in the deep ultraviolet (UV) region with a nanosecond-pulsed Nd-YAG laser system that consists of a tunable laser and a cooled CCD camera. Clear fluorescence images were obtained by time-resolved imaging with a 255- to 425-nm band-pass filter, which cuts off strong fluorescence of papers. Although fluorescence can be imaged with any excitation wavelength between 220 and 290 nm, 230 and 280 nm are the best in terms of image quality. However, the damage due to laser illumination was smaller for 266-nm excitation than 230- or 280-nm excitation. Absorption images of latent fingerprints on a high-grade white paper are also obtained with our imaging system using 215- to 280-nm laser light. Shorter wavelengths produce better images and the best image was obtained with 215 nm. Absorption images are also degraded slightly by laser illumination, but their damage is smaller than that of fluorescence images.
我们使用由可调谐激光器和冷却电荷耦合器件（CCD）相机组成的纳秒脉冲钕钇铝石榴石（Nd-YAG）激光系统，研究了深紫外（UV）区域高档白纸上指纹的荧光成像。通过使用255至425纳米带通滤波器的时间分辨成像获得清晰的荧光图像，该滤波器可截止纸张的强荧光。尽管在220至290纳米之间的任何激发波长下都可以对荧光进行成像，但就图像质量而言，230至280纳米是最佳的。然而，266纳米激发下激光照射造成的损伤比230或280纳米激发下的要小。我们的成像系统还使用215至280纳米激光获得了高档白纸上潜在指纹的吸收图像。较短波长产生的图像更好，215纳米时获得了最佳图像。吸收图像也会因激光照射而略有退化，但其损伤小于荧光图像。
