扫描多光谱红外反射成像技术(SMIRR):一种用于艺术品诊断的先进工具。
Scanning multispectral IR reflectography SMIRR: an advanced tool for art diagnostics.
机构信息
Istituto Nazionale di Ottica (CNR-INO), Largo E. Fermi 6, 50125 Florence, Italy.
出版信息
Acc Chem Res. 2010 Jun 15;43(6):847-56. doi: 10.1021/ar900268t.
Spectral imaging technology, widely used in remote sensing applications, such as satellite or radar imaging, has recently gained importance in the field of artwork conservation. In particular, multispectral imaging in the near-infrared region (NIR) has proved useful in analyzing ancient paintings because of the transparency of most pigments and their varied reflectance changes over this spectral region. A variety of systems, with different detectors and filtering or dispersing technologies, have been implemented. Despite the recognized potential of multispectral NIR imaging, which provides information on both spectral and spatial domains (thus extending the capabilities of conventional imaging and spectroscopy), most of the systems currently used in art diagnostics have limitations. The technology is still in its early stages of development in this field. In this Account, we present the scanning multispectral IR reflectography (SMIRR) technique for artwork analysis, together with an integrated device for the acquisition of imaging data. The instrument prototype is a no-contact optical scanner with a single-point measurement of the reflectance, capable of simultaneously collecting a set of 14 spatially registered images at different wavelengths in the NIR range of 800-2300 nm. The data can be analyzed as a spectral cube, both as a stack of wavelength resolved images (multi-NIR reflectography) and as a series of point reflectance spectra, one for each sampled pixel on the surface (NIR spectrometry). We explore the potential of SMIRR in the analysis of ancient paintings and show its advantages over the wide-band conventional method. The multispectral option allows the choice of the most effective NIR bands and improves the ability to detect hidden features. The interband comparison aids in localizing areas of different pictorial materials with particular NIR reflectance. In addition to the analysis of single monochromatic images, enhancement procedures involving the joint processing of multispectral planes, such as subtraction and ratio methods, false color representation, and statistical tools such as principal component analysis, are applied to the registered image dataset for extracting additional information. Maintaining a visual approach in the data analysis allows this tool to be used by museum staff, the actual end-users. We also present some applications of the technique to the study of Italian masterpieces, discussing interesting preliminary results. The spectral sensitivity of the detection system, the quality of focusing and uniformity of the acquired images, and the possibility for selective imaging in NIR bands in a registered dataset make SMIRR an exceptional tool for nondestructive inspection of painting surfaces. The high quality and detail of SMIRR data underscore the potential for further development in this field.
光谱成像技术广泛应用于遥感领域,如卫星或雷达成像,最近在艺术品保护领域也得到了重视。特别是,近红外(NIR)多光谱成像在分析古代绘画方面非常有用,因为大多数颜料都是透明的,并且在这个光谱区域内它们的反射率变化多样。已经实施了各种具有不同探测器和滤波或色散技术的系统。尽管多光谱近红外成像具有公认的潜力,它提供了光谱和空间域的信息(从而扩展了常规成像和光谱学的能力),但目前在艺术诊断中使用的大多数系统都存在局限性。该技术在该领域仍处于早期发展阶段。在本报告中,我们介绍了用于艺术品分析的扫描多光谱红外反射成像(SMIRR)技术,以及用于获取成像数据的集成设备。仪器原型是一种非接触式光学扫描仪,具有单点反射率测量功能,能够同时在 800-2300nm 的近红外范围内以 14 个不同波长的空间注册图像集进行采集。数据可以作为光谱立方体进行分析,既可以作为一组按波长分解的图像(多近红外反射成像),也可以作为每个表面采样像素的一系列点反射率光谱(近红外光谱学)。我们探讨了 SMIRR 在分析古代绘画中的潜力,并展示了它相对于宽带常规方法的优势。多光谱选项允许选择最有效的近红外波段,并提高检测隐藏特征的能力。波段间比较有助于定位具有特定近红外反射率的不同绘画材料区域。除了分析单个单色图像外,还可以对多光谱平面进行联合处理,例如减法和比值方法、假彩色表示以及主成分分析等统计工具,以提取附加信息,从而应用于注册图像数据集。在数据分析中保持直观的方法可以使博物馆工作人员,即实际的最终用户,使用该工具。我们还介绍了该技术在意大利杰作研究中的一些应用,讨论了有趣的初步结果。检测系统的光谱灵敏度、聚焦质量和获取图像的均匀性,以及在注册数据集的近红外波段中进行选择性成像的可能性,使 SMIRR 成为一种用于绘画表面无损检测的特殊工具。SMIRR 数据的高质量和细节突出了该领域进一步发展的潜力。