基于光度立体成像与灰度值变化的签名笔迹检验  

Signature Handwriting Examination Based on Photometric Stereo Imaging and Change of Gray Value

作　　者：周鹏[1] 高树辉[1] Zhou Peng;Gao Shuhui(School of Investigation,People′s Public Security University of China,Beijing 100038,China)

机构地区：[1]中国人民公安大学侦查学院,北京100038

出　　处：《激光与光电子学进展》2021年第8期266-278,共13页Laser & Optoelectronics Progress

基　　金：上海市现场物证重点实验室开放课题基金(2020XCWZK07)。

摘　　要：利用光度立体成像法,重建签名笔迹立体形态样本集,基于样本图灰度数据进行量化分析,提出区域灰度差异度D和相邻区域灰度均值变化趋势V′两个特征指标,研究签名笔迹立体形态图灰度指标与签名者书写特征的相关性。实验中共采集5名志愿者1000枚签名共计2600个单字样本集,500枚临摹签名共计1300个单字样本集,在Lib-SVM分类器的基础上利用Canny算子提取边缘特征,通过膨胀腐蚀处理进行特征区域定位,并使用局部二值模式(LBP)算子提取特征区域纹理信息作为分类的特征向量。实验结果表明,经过图像处理后的特征区域二分类模型,可以有效区分真实和临摹签名笔迹的立体形态图,相比特征区域未处理的样本有较高的准确率,由此证明人工智能结合立体成像检测签名笔迹立体形态的方法具有科学性和可行性,能为签名笔迹鉴定提供技术支持。In this study,photometric stereo imaging is used to reconstruct the stereo morphology of signature handwriting.Based on gray data quantitative analysis of the sample image,two characteristic indicators of the regional gray difference D and the gray average change trend V′of adjacent regions gray levels are proposed to examine the correlation between three-dimensional(3 D)morphological images of the signature handwriting and the signer’s writing characteristics.In the experiment,1000 signatures from five volunteers are collected to form 2600 single-character sample sets,and 500 copied signatures are collected to form 1300 single-character sample sets.Based on the Lib-SVM classifier,the Canny operator is used to extract edge features,and image processing,such as dilation and corrosion,is performed.The method locates the feature region and uses the LBP(Local Binary Pattern)operator to extract the texture information of the feature region as a feature vector for classification.The experimental results show that a binary classification model of the feature area processed using image processing technology can effectively differentiate the 3 D morphology of the real and copied signature handwriting.The proposed method has a higher accuracy rate than the unprocessed sample in the characteristic area,proving that the method is scientific and feasible.It can provide technical support for signature-handwriting examination.

关 键 词：成像系统 光度立体成像 签名笔迹检验 灰度均值 灰度差异度 图像处理 

分 类 号：TP391.4[自动化与计算机技术—计算机应用技术]