【作者】 孟庆霞；

【导师】 庞其昌；

【作者基本信息】 暨南大学 ， 光学， 2004， 硕士

【摘要】 在重大刑事案件的破案过程中，指纹取证是极其重要的环节，指纹留下的痕迹有时成为破案的关键。能及时准确地采到有效指纹，对案件的侦破有很大的帮助。为改善现有勘测手段的不足，我们与省公安厅和星博数字公司合作，共同研发可视多光谱痕迹检测系统。本课题的目标是采用摄像及监视系统，结合荧光粉末法替代传统的人工探测，以最大限度地消除主观误差和减轻劳动强度，提高工作效率。 论文详细地阐述了光致发光材料的发光机理，分析了荧光产生的内部及外部原因；分析了荧光的产生和变化与晶格结构的关系；分析了离子极化产生的原因及荧光结构对荧光强度的影响。分析讨论了荧光产生过程中的电子跃迁规律、荧光寿命和量子效率、荧光的激发光谱与发射光谱的关系。为可视多光谱痕迹检测系统中使用荧光粉末显现指纹提供理论依据。 使用不同光源照射客体对指纹显现效果就不同，光源的照射角度不同时指纹的显现效果也不同，论文对此作了对比及分析。并对是否使用滤光片，使用何种滤光片进行了充分的实验论证。论文对不同类型指纹对荧光粉的敏感度作了比较与分析。分析讨论了不同客体上的指纹显现的清晰度。 实验论证为系统设计及使用提供了理论依据： 1．光源或检测镜头的转角是可调的，其大小要达到最佳的取像角度，使光源的反射光斑不影响指纹显现。 2．选择最佳荧光粉与滤光片组合，比较后给出较佳的参考结果。减少在使用时多方面的重复比较，减轻劳动强度。 3．检测仪一体化后，要保证其重量不能太重，以方便携带。更多还原

【Abstract】 During the course of clearing up many serious criminal cases, to obtain fingerprints is among the most vital steps. Sometimes fingerprint traces turn to be linchpins of breaking criminal cases. To obtain fingerprints accurately and effectively is even more helpful to make the case clear. In order to improve the present insufficient measuring means, we cooperate with the Provincial Police Authority and Xingbo Digital Company in developing a video multi-spectrum measuring system for checking traces. Instead of using the traditionally used measurement executed by human beings, this study adopts a device system combined of videos and monitors, together with fluorescence powder. This new approach aims at eliminating subjective errors to the uttermost as well as lessening labors strength so as to enhance work efficiency.This paper particularly explains the excitation mechanism for photoexcitation material and analyzes internal and external reasons of emitting fluorescence, the relationship between emitting and changing of fluorescence and lattice structure. The paper also analyzes the reasons of ions polarization and lattice structure’s influence on fluorescent intensity. Besides, the paper discusses electron jump law during the course of emitting fluorescence, fluorescence life, quantum efficiency and the relationship between the fluorescent emission spectrums and transmission spectrums. The paper provides, at the same time, a theoretic basis for using fluorescent powder when checking traces by using multi-spectrum measuring system.If light sources are different, fingerprints are revealed in the same way. Likewise, beam’s angles different, fingerprints not the same way either. This paper makes relevant analysis and comparison on the above-mentioned facts and provides sufficient experimental argumentations on whether to use filters and whatfilters to be used. The paper makes analysis and comparison on the sensitivity of varied fingerprints to fluorescent powder. The paper also analyzes the degrees of clarity of the fingerprints revealed.The experimentation provides a theoretic basis for devising the system and using it:1. The angles of light source or measuring lens can be adjusted. It can be adjusted to the most suitable angle to take pictures. Reflex spots of light source cannot affect fingerprints to appear.2. The best filters are selected to match for fluorescent powder in varied condition. After the comparison, a better reference can be provided. This way can reduce troubles and ease off work intensity.3. When the device comes out, its weight shall not be too heavy so that it can be carried conveniently.更多还原