Analysis of Handwriting Variation and Development of High Performance Computer-Based System to Support Forensic Examination of Japanese Documents

这项研究项目已进行了两年多(2003-2004年)。本研究项目的目的是建立笔迹的个性化，并开发一个高性能的法医文书鉴定支持系统。我们能够达到这个研究项目的目的。本课题取得的研究成果总结如下：(1)在传统笔迹提取方法的基础上加入颜色信息，对笔迹提取方法进行了改进。通过实验验证了该提取方法即使在笔迹和印鉴相互叠加的情况下，也能从各种类型的文件中准确地提取出笔迹和印鉴。(2)法医笔迹鉴定是基于每个人都有不同于其他人的笔迹的一致笔迹的假设。通过许多案例研究，这一假设已被主观接受。然而，笔迹的个体性还没有以科学和定量的严谨性来确定，因此它作为法医证据的可采性可能会受到质疑。提出了一种基于“变异熵”的笔迹个性验证方法，并进行了基于模式匹配的笔迹验证实验。通过实验，证实了变异熵作为评价笔迹整体形状变异的指标是合适的。将变异熵与笔迹验证结果相结合，为笔迹个性的验证提供了可能。(3)开发了笔迹笔画结构的测量工具。我们正在利用统计分析的方法对笔迹笔画结构的个性进行调查，我们的目标是在未来结合上述结果开发一个完整的系统来支持法医文书鉴定。

This research project has been carried out over two years (2003-2004). The aims of this research project are to establish individuality of handwriting and to develop a high performance support system for forensic document examination. We were able to achieve the aim of this research project. The summary of results obtained by the research project are as follows :(1) We have improved a handwriting extraction method by adding color information to the conventional extraction method. Through an experiment, it confirmed that this extraction method can extract precisely handwriting and seal imprint from various types of documents, even if handwriting and seal imprint are superimposed each other.(2) Forensic handwriting examination is based on the hypothesis that each individual person has consistent handwriting that is distinct from the handwriting of other individuals. This hypothesis has accepted subjectively through many case studies. However the individuality of handwriting has not been established with scientific and quantitative rigor, therefore its admissibility as forensic evidence can be questioned. We proposed a method for validating handwriting individuality using a "variation entropy" and a writer verification experiment based on the pattern matching method. Through the experiments, it was confirmed that the variation entropy was appropriate for evaluating the variation of handwriting as whole shape. We got a prospect to be possible of validating handwriting individuality by combining the variation entropy and writer verification results.(3) We have developed a measurement tool of handwriting stroke structure. We are now investigating on the individuality of stroke structures of handwriting by using a statistical analysis method.We aim to develop a complete system to support forensic document examination by combining above results in the future.