Volume 40, Issue 1 (January 1995)
Fingerprint Imaging with a Confocal Scanning Laser Macroscope
The scanning laser macroscope is a new scanning beam confocal imaging system that scans up to 7.5 cm × 7.5 cm in 5 seconds. One of its unique features is a telecentric f-theta lens that focuses the incoming beam from a low power laser to a 10 µm spot on the sample. The f-theta lens provides a linear scan, and has a flat focal plane. The macroscope is described in detail and its operation is discussed. Confocal reflected-light images of latent fingerprints were obtained on several different materials. Fluorescence images of Rhodamine-treated samples were also obtained. We also show a reflection image of a fingerprint recorded by scanning the finger in air. Other possible uses of the macroscope in forensics include time-resolved fluorescence, imaging of fluorescent gels used in DNA fingerprinting, IR fluorescence imaging of documents, detecting and recording fluorescence images of latent fingerprints excited with UV radiation, and entering file prints into the computer for storage.