NIR imaging instrumentation

The tunable filter technology also has distinct PAT advantages. Rapid timing of discrete wavelengths through software control and no moving parts enables the collection of data sets comprising approximately 80 000 spectra in a matter of a couple of minutes. For most 

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Evolution of NIR Imaging Instrumentation 8.3.1 Spatially resolved spectroscopy - mapping... 

Lewis, E. N., DuBois, J. and Kidder, L. H. NIR imaging, instrumentation and its applications to agricultural and food engineering. In Near Infrared Spectroscopy in Food Science and Technology (Yukihiro Ozaki, W. Fred McClure, and Alfred Christy, eds), John Wiley Sons, in press. 

In the following sections the instrumentation used for the apphcation examples described in this chapter will be discussed in some detail. Specifically, the basic instrumental features of the two imaging systems, different possible measurement modes and the occurrence of instrument-related and sample-related artifacts and misinterpretations will be outiined. Because NIR imaging instruments are simpler in design, these will be discussed first. 

In a typical NIR spectroscopic measurement, spectral contribution from the entire corn kernel is averaged in a single spectmm. In the following example, the chemical information contained in the NIR spectrum and the spatial resolution provided by NIR imaging instrumentation were used to investigate the three-dimensional biochemistry and morphology of a corn kernel. 

Figure 8.1 Schematic representation of NIR chemical imaging instrument operating in diffuse reflectance mode. Radiation from the illumination source interacts with the sample. Light reflected off of the sample is focused onto a NIR sensitive 2D detector after passing through a solid-state tunable wavelength selection filter.

Near-infrared chemical imaging instrumentation is rugged and flexible, suitable for both the laboratory and the manufacturing environment. Therefore analysis methods developed in the laboratory can often be tailored for implementation near-line or at-line. NIR-CI is also a massively parallel approach to NIR spectroscopy, making the technique well suited for high-throughput applications. 

Figure 8.8 A 58 mm x 46 mm NIR image of a Tempo top ply taken through a macroobjective on the MatrixNIR instrument (Spectral Dimensions). This image is a band integration map of the lotion absorption (1160-1260 nm) from a 4 scan, 24 frame data collection smoothed 13 points and offset corrected. The white box in the upper left shows the 5 mm x 5 mm size of images collected by the Perkin-Elmer Spotlight instrument (see Figs 8.6 and 8.7) for comparison.

Figure 8.10 A 1.4 mm x 1.8 mm NIR image of a Tempo top ply taken through a lOx microscope objective. This image is about three times smaller than the 5 mm x 5 mm images collected on the Perkin-Elmer Spotlight instrument.

Figure 9.1 (a) The NIR imaging system (b) The optical scheme of the instrument for diffuse-reflection measurements of a powder sample. 

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