基于同色系光谱特征指数的壁画颜料识别方法  

Method for identification of mural pigments based on the spectral characteristic index of the same color category

作　　者：汪雨 吕书强 侯妙乐[1,2] 孙宇桐 李丽红[3] WANG Yu;LYU Shuqiang;HOU Miaole;SUN Yutong;LI Lihong(School of Geomatics and Urban Spatial Informatics,Beijing University of Civil Engineering and Architecture,102616,China;Beijing Key Laboratory for Architectural Heritage Fine Reconstruction&Health Monitoring(Beijing University of Civil Engineering and Architecture),102616,China;Yungang Research Institute,Datong 037007,China)

机构地区：[1]北京建筑大学测绘与城市空间信息学院,北京102616 [2]建筑遗产精细重构与健康监测北京市重点实验室(北京建筑大学),北京102616 [3]云冈研究院,山西大同037007

出　　处：《文物保护与考古科学》2024年第5期96-103,共8页Sciences of Conservation and Archaeology

基　　金：国家重点研发计划(2022YFF0904400);国家自然科学基金(42171356,42171444)资助。

摘　　要：壁画是人类文明的瑰宝,具有极高的历史意义与艺术价值,而颜料是壁画表面信息的重要组成部分。针对壁画表面同色系颜料肉眼难以辨认的问题,提出了基于归一化光谱指数的颜料识别方法。利用地物波谱仪获取颜料的光谱反射率,覆盖波长为350~2500 nm。通过一阶导数初步选择特征波段,利用欧氏距离作为可分性指标确定最终4个特征波段,构建归一化光谱特征指数。通过区分度来选取最优指数,区分度大于0.5则认为颜料易于区分。以绿色系颜料为例,选取氯铜矿、铜绿、绿玛瑙、绿松石、群绿、石绿、云母绿7种绿色颜料,构建了绿色系不同颜料的光谱特征指数,并以同样的方法构建了其他色系的光谱特征指数。以模拟壁画与云冈石窟06窟西壁壁画作为验证数据,利用所提出的同色系光谱特征指数、光谱角、欧氏距离、光谱特征拟合、二进制编码匹配分别进行颜料识别。结果表明所提方法能有效识别同色系颜料,对于壁画同色系颜料的快速准确识别具有实践意义。Mural paintings and other painted cultural relics are precious cultural heritage with great artistic value and historical significance.The pigment is an important part of the information on the surface of a mural painting,and it is extremely important to identify the pigment type quickly and accurately.Due to the non-renewable nature of cultural relics,the use of non-destructive means of detection has become necessary.The hyperspectral technology has become an important research tool for identifying mural pigments due to its advantages of non-destructive detection,high spectral resolution,as well as the union of imagery and spectrum.In this study,a pigment identification method using Euclidean distance(ED)combined with the normalized spectral characteristic index(NDSI)is proposed to address the problem of differentiating pigments with the same color in murals.Firstly,seven green mineral pigments,including atacamite,verdigris,green agate,turquoise,ultramarine green,malachite,and mica green,were selected and painted on rice paper to form samples.We obtained their reflectance in the wavelength of 350-2500 nm using an ASD FieldSpec4 spectroradiometer.Secondly,the spectral first-order derivatives were utilized in the selection of characteristic bands,which can highlight the curve trend.In this case,the bands with a derivative value of 0 are the peaks and troughs of a curve,which can be considered as characteristic bands.Taking the atacamite pigment as the target pigment,for the i-th characteristic band of atacamite pigment,we calculated the sum of the Euclidean distances between atacamite and other pigment spectra in this band to obtain the distance index D i corresponding to the i-th characteristic band.The distance indices for all characteristic bands were sorted in a descending order,and the four bands corresponding to the top four largest distance indices were selected as the final characteristic bands of the target pigment.Then,the NDSI was constructed using these characteristic bands,which are given by NDSI=12 R

关 键 词：高光谱遥感 光谱指数 颜料识别 特征波段选择 

分 类 号：K879.41[历史地理—考古学及博物馆学]