The non-invasive in-situ infrared analysis of art objects was first accomplished with single point portable analysis systems. A small FTIR spectrometer could be brought to the object of interest and a quick analysis performed. This allowed objects to be analyzed without the need of removal from the gallery or removal of small samples from the object. The analysis is accomplished by illuminating the sample with infrared light and collecting the signal reflected by the sample. A natural extension of this method would be the replacement of the single detector element with a many pixel array detector such as a Photovoltaic Mercury Cadmium Telluride (PV-MCT) focal-plane array (FPA). FPA’s have been used for many years in the remote sensing of airborne chemicals, hazardous material, and spilled liquids .2-5 The conventional remote sensing infrared spectrometer with a single detector records the spectrum from a single field of view in seconds, and in contrast imaging spectrometers acquire thousands of spectra per second. As the pixels from state-of-the-art FPA detectors are small, microscopic data can be collected at high magnification over small areas or larger areas can be analyzed with less resolution. Such analyses can be accomplished in passive or active modes of analysis. Spatial and spectral information may be combined in order to improve the determination of chemical distribution. Art objects present unique challenges to the remote measurement concept. The objects typically do not emit a signal strong enough for passive detection and the introduction of a high temperature source could potentially damage the object in question. Also, traditional SiC sources were designed to illuminate small areas and had too low a power output to be useful for large fields of interest. Objects can also be irregular in shape. A preliminary study of a variety of art objects has been performed to determine the feasibility of applying full-field middle infrared imaging to objects of interest. The large depth-of-field of a stand-off imaging system like the HI90 allows almost any object to be analyzed quickly and easily.
