Centre for Sustainable Heritage, The Bartlett School of Graduate Studies, University College London, Gower Street (Torrington Place Site), London WCIE 6BT, United Kingdom.
Anal Chem. 2011 Jul 1;83(13):5101-6. doi: 10.1021/ac200986p. Epub 2011 Jun 3.
Until recently, applications of spectral imaging in heritage science mostly focused on qualitative examination of artworks. This is partly due to the complexity of artworks and partly due to the lack of appropriate standard materials. With the recent advance of NIR imaging spectrometers, the interval 1000-2500 nm became available for exploration, enabling us to extract quantitative chemical information from artworks. In this contribution, the development of 2D NIR quantitative chemical maps of heritage objects is discussed along with presentation of the first quantitative image. Further case studies include semiquantitative mapping of plasticiser distribution in a plastic object and identification of historic plastic materials. In the NIR imaging studies discussed, sets of 256 spatially registered images were collected at different wavelengths in the NIR region of 1000-2500 nm. The data was analyzed as a spectral cube, both as a stack of wavelength-resolved images and as a series of spectra, one per each sample pixel, using multivariate analysis. This approach is only possible using well-characterized reference sample collections, as quantitative imaging applications need to be developed, thus enabling spatial maps of damaged and degraded areas to be visualized to a level of chemical detail previously not possible. Such quantitative chemical mapping of vulnerable areas of heritage objects is invaluable, as it enables damage to historic objects to be quantitatively visualized.
直到最近，光谱成像在文物科学中的应用主要集中在对艺术品的定性检查上。这部分是由于艺术品的复杂性，部分是由于缺乏合适的标准材料。随着近红外成像光谱仪的最新进展，1000-2500nm 的区间可用于探索，使我们能够从艺术品中提取定量化学信息。在本贡献中，讨论了文物对象的二维近红外定量化学图谱的发展，并介绍了第一张定量图像。进一步的案例研究包括在塑料物体中定量绘制增塑剂分布的半定量图谱以及鉴定历史塑料材料。在讨论的近红外成像研究中，在 1000-2500nm 的近红外区域以不同波长收集了 256 组空间配准的图像。使用多元分析对数据进行分析，作为光谱立方体，既作为一组按波长分辨的图像，也作为一系列光谱，每个样品像素一个。这种方法仅使用特征良好的参考样品集是可行的，因为需要开发定量成像应用程序，从而能够以以前不可能的化学细节水平可视化受损和退化区域的空间图谱。对文物脆弱区域进行这种定量化学绘图是非常宝贵的，因为它能够使历史文物的损坏以定量方式可视化。
