文物红色系颜料高光谱识别指数研究  

Hyperspectral Indices for Identification of Red Pigments Used in Cultural Relic

作　　者：李德辉 吴太夏[1] 王树东 李哲华 田意伟 费晓龙 刘洋[1] 雷勇[3] 李广华[3] LI De-hui;WU Tai-xia;WANG Shu-dong;LI Zhe-h ua;TIAN Yi-wei;FEI Xiao-long;LIU Yang;LEI Yong;LI Guang-hua(School of Earth Sciences and Engineering,Hohai University,Nanjing 211100,China;Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100094,China;The Palace Museum,Beijing 100009,China)

机构地区：[1]河海大学地球科学与工程学院,江苏南京211100 [2]中国科学院空天信息创新研究院,北京100094 [3]故宫博物院,北京100009

出　　处：《光谱学与光谱分析》2022年第5期1588-1594,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(41371359,41671362);江苏特聘教授项目(2016/B19053)资助。

摘　　要：红色系矿物颜料曾被艺术家们大量地使用在古画和古建筑上。正确地识别出不同种类的红色系颜料对于文物监测与修复具有重要意义。传统的颜料识别主要依靠化学分析,不仅识别速度慢、识别范围小,而且对文物进行取样操作会造成文物的永久损伤。高光谱技术对颜料进行无损识别可以很好地解决这些问题。选用辰砂、胭脂、银朱、朱膘、朱砂、赭石、赭粉、铁红、土红、西洋红10种红色系矿物颜料作为研究对象,使用地物光谱仪在暗室中获取这10种红色系颜料在350~2500nm波段内的高光谱数据原始数字(DN)影像,经反射率校正,得到可直接用于光谱分析的反射率数据及光谱曲线。基于10种红色系颜料不同的光谱曲线特性,分两步筛选获取被区分颜料即目标颜料的光谱特征波段。取目标颜料光谱曲线的极值点作为特征波段,可以筛选得到目标颜料的初选光谱特征波段。将其余9种颜料在初选光谱特征波段上对应的反射率与目标颜料在此波段上的反射率做差,对于差值,筛去离群值后求平方和,不同波段对应不同的差值平方和,选取差值平方和较大的前4个波段作为优选后的光谱特征波段。基于归一化光谱指数模型公式[NDSI=(R_(a)-R_(b))/(R_(a)+R_(b)),R_(a)和R_(b)分别为目标颜料在光谱特征波段a和b处的反射率值]对10种红色系颜料分别构建归一化光谱指数,将目标颜料与其余9种红色系颜料在同一光谱特征波段处计算得到的光谱指数进行对比分析,计算目标颜料光谱指数与其余颜料光谱指数的区分度,以此作为评价区分效果的指标。对于最终优选出的4个光谱特征波段,可构建6个归一化光谱指数,选择最小区分度最大的归一化光谱指数作为目标颜料的光谱特征指数。研究结果显示,在通过各自的光谱特征指数进行区分时,每种目标颜料与其他颜料的最小区分度都保持在0.7以Red mineral pigments have been widely used in ancient paintings and ancient buildings by artists.It is of great significance to correctly identify different kinds of red pigments to monitor and restore cultural relics.Traditional pigment identification mainly relies on chemical analysis,which has a slow identification speed and small identification range and will cause permanent damage to cultural relics by sampling operation.Nondestructive identification of pigments by hyperspectral technology can solve these problems well.In this study,ten red mineral pigments,namely CinnabarⅠ,Rouge,Vermilion,Zhi Xi,CinnabarⅡ,Ochre,Ochre powder,Iron oxide red,Terra Rossa and Western red,were selected as the objects of study.The original digital(DN)images of the hyperspectral data of the 10 red pigments in the band of 350~2500 nm were obtained by using a ground object spectrometer in an optical darkroom,and the reflectance data and spectral curves which can be directly used for spectral analysis were obtained by reflectance correction.Based on the characteristics of different spectral curves of 10 red pigments,the spectral characteristic bands of the distinguished pigments,namely target pigments,were obtained by two-step screening.By taking the extreme point of the spectral curve of the target pigment as the characteristic band,the primary spectral characteristic band of the target pigment can be screened.The reflectance of the other 9 pigments corresponding to the primary spectral characteristic band was differentiated from that of the target pigment in this band.As for the difference,the sum of squares was calculated after screening outliers.Different bands correspond to different sums of squares of differences,and the first 4 bands with larger sums of squares of differences were selected as the optimized spectral characteristic bands.Based on the normalized spectral index model formula(NDSI=(R_(a)-R_(b))/(R_(a)-R_(b)),R_(a)and R_(b)are the reflectance values of target pigments at spectral characteristic bands a and b resp

关 键 词：高光谱技术 文物 红色系颜料 光谱指数 

分 类 号：TP75[自动化与计算机技术—检测技术与自动化装置]