Comparison Of Potential Fingerprints Detected By The Tracking Color Separation Imaging System And Short-Wave UV Reflection Photography

The extraction of potential fingerprints has a crucial role in the detection of criminal cases.However,the extraction of potential fingerprints is also one of the difficulties in forensic science research.The traditional optical non-destructive methods for extracting potential fingerprints includes color separation photographic method,directional reflex photographic method,ultraviolet reflex photographic method,infrared reflex photographic method,and photoluminescence photographic method.People's Public Security University of China and Iris Technology Technology Co.Ltd.are based on the traditional optical non-destructive fingerprint extraction method,and the principle of color separation photography,which uses the electro-optic effect of the crystal to develop adjustable narrowband filters,with the color separation imaging system,jointly developed tracking color separation imaging system.The experiment of this subject is mainly divided into two parts: The first part is the basic research on the shooting conditions and application scope of the tracking color separation imaging system,and it is explored that the tracking color separation imaging system can obtain the most light distribution angle and shooting distance.The best appearance and the potential fingerprints that can be used to capture which objects;the second part compares the imaging effect of the tracking color separation imaging system with the short-wave ultraviolet reflex photography,and compares the advantages of the two for potential fingerprints in order to provide guidance for crime scene investigation.This experiment breaks through the traditional visual assessment method for visualizing effects,and used Visual Studio 2008 to write a special visual effect comparison program:ContrastTool,which realizes accurate and free selection of sampling points on fingerprints and backgrounds to calculate the average luminance of fingerprints.Background Weber contrast the average brightness,and then compare the advantages and disadvantages of the two methods of visualization.And eventually figure out a new,scientific quantitative assessment method for the optical appearance of potential fingerprints.The research showed that:1.The tracking color separation imaging system has a good visual effect on the potentialfingerprints on the colored and impermeable smooth surfaces.2.The tracking color separation imaging system has a light distribution angle of 15 degrees and the shooting distance.The appearance effect is the best when it is about 25 centimeters,and the effect lines with clear lines and obvious contrast can be obtained.3.The potential fingerprints of different receiving bands in the tracking color separation imaging system were significantly affected by the color of the target marks.4.ContrastTool can be widely used to compare the appearance of trace photographs to achieve accurate quantitative evaluation of the appearance effect.5.For the potential fingerprint on the colored object,the tracking color separation imaging system appeared better than the short-wave UV reflection photography,and for the potential fingerprints on the white or the colors that are close to white objects,the tracking color separation imaging system cannot be a good effect.6.Tracking color separation imaging system is easy to operate,easy to carry,suitable for extensive use in the scene survey.