指纹鉴定意见是指纹鉴定人员结合自身从业经验并通过一系列的检验获得的，整个指纹鉴定过程是由感性上升至理性的认知过程。在指纹鉴定过程中，指纹鉴定人员辨别现场指印中细节特征点的能力是影响指纹鉴定意见的重要因素，在获得样本指印后，对照样本指印确认现场指印中的细节特征点则直接决定着鉴定意见。考察指纹鉴定人员在检验现场指印时点取细节特征点的结果，以及获得样本指印后对现场指印细节特征的变动情况，可以分析指纹鉴定人员在不同条件下判断现场指印细节特征点的认知变化，有助于判断指纹鉴定人员在分析阶段理解现场指印特征的程度，有助于考察样本指印对指纹鉴定人员点取特征产生的影响，进而分析点取特征稳定性与指纹鉴定能力之间的关系，为指纹管理人员评估指纹鉴定人员鉴定能力提供一定帮助。本文重点针对指纹鉴定人员点取特征的稳定性进行研究，邀请106家鉴定机构对4组指印进行特征点取，使用统计学工具对点取特征的结果进行统计与分析。实验结果表明：不同机构指纹鉴定人员点取特征的稳定性存在一定的差异性；指纹鉴定人员点取特征的稳定性与现场指印质量之间存在显著关系，高质量指印鉴定过程中，指纹鉴定人员选取特征的稳定较高，且样本指印未对鉴定人员的认知能力产生影响，低质量指印鉴定过程中，指纹鉴定人员在分析阶段和比对阶段点取特征的稳定性较差，尤其在高低质量区交界处点取特征的离散程度较高；点取特征变化指数I 可有效衡量指纹鉴定人员点取特征的稳定性，指纹管理人员可依据I 值变化程度，评估机构或者鉴定人员的鉴定水平，进而采取相应培训措施，提高指纹鉴定过程中点取特征的稳定性，确保指纹鉴定质量。%The decision of fingerprint identification depends on the fingerprint examiner’s knowledge and experience. The fingerprint identification process is a recognition process which can be described as a process from perceptual cognition to rational cognition. During the process, one of the factors that impacts the quality of fingerprint identification is the capability of the fingerprint examiner. Fingerprint examiners select corresponding minutiae on fingermark in comparison phase and the capability can be measured by fingerprint examiners’ stability of minutiae selection. Some research has demonstrated that stability of minutiae selection has influenced the quality of fingerprint identification conclusion, hence it is critical for conducting such fundamental research on stability of minutiae selection for Chinese fingerprint examiners. Our research is focused on analysis of stability of minutiae selection between analysis phase and comparison phase and can help us to understand: how fingerprint examiners understand the minutiae of fingermark in analysis phase; how to control fingerprint impacts fingerprint examiners’ decision in minutiae selection in comparison phase; what is the relationship between stability of minutiae selection and fingerprint identification ability. In this study 106 fingerprint agencies around China were invited to take a proficiency test and finish four trials from the same source. The data were collected by web-based software and were analyzed by R statistical software. The results show that different analysts performed differently and fingerprint quality impacted the stability of minutiae selection. If fingerprint quality values were high, examiners reported highly stable minutiae selection, while they reported highly unstable minutiae selection if quality values were low, especially on the border of high quality and low quality area. Stability of minutiae selection can be effectively measured by I, which is defined as Minutiae Variability Index. This suggests that there is a need for developing a tool to assess the quality of fingermarks to predict the performance of fingerprint examiners during the fingerprint identification process. According to distribution of I, manager can effectively evaluate identification ability of agency or examiner and then take effective measurement to improve the stability of minutiae selection (such as document identification activity and add more verification stage) and make sure the quality of the fingerprint identification.
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