Development Of UV Fluorescence Photography

The forensic photography which focuses on the evidence emerges, since thecriminal cases become higher technological and more complicated. UV fluorescencephotography of the forensic photography which aims at the potential wound typebecomes significant as the wound type was usually used as physical evidence toprovide clues. Domestic studies and application on UV fluorescence photography arerarely. Although UV fluorescence photography has already been applied overseas,studies about improvement of fluorescence intensity in system were hardly to befound. This thesis aims at UV fluorescence photography, and study was carried outon realization and improvement of wounds’ identification.Through the studies of skin structure, skin compositions, optical properties andphysical properties of scar, the special UV excitation spectrum of330-385nmstimulating skin fluorescence peak is obtained based on Stokes principle. Woundedwould turn dark as special component in wound absorb UV spectrum strongly; whilehealthy skin stimulate strong fluorescent light and turns bright. The schematicdiagram of the UV fluorescence photography system is obtained by comparingreflective images from both the healthy and wounded skin. Then UV fluorescencephotography schematic diagram was obtained.The UV fluorescence photography system is mainly composed of three parts:ultraviolet source, filters and digital camera. First of all, special parameters of UVband-pass filter used in UV fluorescence photography are obtained based on the UVfluorescence photography schematic diagram: the band330-385nm is the hightransmission region, where minimum transmission is85%. While the bands of200-325nm390-780nm are high reflective, where the reflectivity is higher than90%.Then film system0.5L(HL)6(1.2H1.2L)6(1.6H1.6L)6H0.5L is designed and optimizedby using TFC, and the errors was analyzed. Finally, by considering factors ofimaging quality requirements by the law, safety, cost and collocation of relationshipbetween devices, special parameters of the other instruments was got, and for the first time UV fluorescence photography system with metal halide lamp as source is built.Results of identification on scar by using the UV fluorescence photographysystem designed and built show that the system built is effective. Contrastexperiments were made between UV fluorescence photography system built here andoverseas common fluorescence photography system. The contrast experimentalresults shows that the UV spectrum330-385nm can make the skin stimulate strongerfluorescence, so the system produces results more clearly and detailed. Conclusionare verified that system built here can improve wounds’ identification.