可见光谱法无损识别壁画文物矿物质颜料的研究

Non-Destructive Identification of Mineral Pigments in Ancient Murals by Visible Spectroscopy

针对取样分析技术破坏壁画文物完整性问题,提出非接触式可见光谱法原位无损识别壁画文物矿物质颜料物质成分和粒径的方法。构建非接触式获取平台原位无损采集壁画文物表面可见光谱;通过调研和实测数据分析,制备了壁画矿物质颜料可见光谱数据库。分析数据库中的光谱数据发现:同种化学成分的颜料具有相同的吸收特性,表现为光谱曲线峰值位置和几何轮廓的相似性;在不同粒径下又呈现出不同的散射特性,表现为光谱曲线幅度的差异性。为此,构建了壁画文物矿物质颜料物质成分和粒径的可见光谱法无损识别流程和识别方法,即提取光谱曲线几何轮廓特征构建表征空间实现了颜料物质成分的识别;在此基础上,提出了矿物质颜料需进行物理特征识别的理念,并建立了光谱曲线幅度积分值与颜料平均粒径间的拟合关系,实现颜料粒径识别。以敦煌莫高窟壁画为例验证了该方法的可行性。

Regarding to the fact that sampling analysis techniques compromise the integrity of the invaluable and nonrenewable cultural relics, the non-invasive identification method, based on visible spectroscopy, was proposed to identified the chemical composition and particle size information of the pigment used ancient murals. A noncontact acquisition platform was established to measure the visible spectrum of the ancient murals. A visible spectral database of the pigment was developed as the reference. After the analysis of the spectrum in the database, the non-invasive identification process and method were constructed based on visible spectroscopy to identify the chemical composition and particle size information of the pigment used ancient murals. First, the geometric feature of the visible spectrum was extracted to construct the feature space for chemical composition identification, and then the amplitude feature of the visible spectrum was integrated and fitted with the mean particle size for particle identification. The method was tested using the murals in Mogao Grottoes.