Transfer of near-infrared monochromator calibrations for tobacco constituents to tilting-filter instruments

Heckman, Robert A.; Diffee, John T.; Milhous, L Arthur

doi:10.1016/s0003-2670(00)85704-9

Cited by 7 publications

(3 citation statements)

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“…There are also many reports of successful applications of some version of this approach in the literature (References 4,25,26,27,43,44,50,56,59,62,63,(65)(66)(67)(68)70,73,87,99). Heckman et al 55 report on the use of a similar approach to transfer calibrations from a monochromator to a tilting filter instrument.…”

Section: Shenk-westerhausmentioning

confidence: 99%

Standardisation and Calibration Transfer for near Infrared Instruments: A Review

Fearn

2001

Journal of Near Infrared Spectroscopy

224

178

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Transferring calibrations between near infrared instruments is not always straightforward, even when the instruments are nominally the same. Problems can include both wavelength shifts and differences in absorbance response between instruments. This review describes a number of chemometric methods that have been developed to aid calibration transfer. The approaches are classified under three headings: making robust calibrations, adjusting calibrations and adjusting spectra. Calibrations can be made more robust, and more transferable, by the appropriate use of spectral pre-treatments that reduce between-instrument variability. Robust calibrations can also be made by pooling data from several instruments when calibrating. Calibrations can be adjusted using skew and bias corrections estimated from a modest number of samples with known reference values. Under the third heading, adjusting spectra, come methods such as piecewise direct standardisation and the patented method of Shenk and Westerhaus that use spectral information from samples measured on two instruments to match the spectral response of the instruments.

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Section: Shenk-westerhausmentioning

confidence: 99%

Standardisation and Calibration Transfer for near Infrared Instruments: A Review

Fearn

2001

Journal of Near Infrared Spectroscopy

224

178

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“…First, tilting-lter spectrometers provide a continuous spectrum from which the second derivative can be computed in virtually the same way it is computed from spectra collected with a dispersion-type laboratory spectrometer. 7 However, tilting-lter instruments have three disadvantages: (1) the change of wavelength is nonlinearly proportional to the angle of the incident light to the lter; (2) the wavelength range of a single lter is sm all; and (3) precise wavelength assignments are dif cult.…”

Section: Introductionmentioning

confidence: 99%

Hand-Held NIR Spectrometry: Part I: An Instrument Based upon Gap-Second Derivative Theory

2001

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A hand-held near-infrared (NIR) meter (called the Gmeter), based upon gap-second derivative (GSD) theory, was designed, constructed, and performance-tested. The design incorporated narrow-band interference filters for isolating the three wavelengths required by the GSD calculations. A microprocessor was included in the design to facilitate both stand-alone and personal computer (PC) operation. The Gmeter was mounted in a caddy for making measurements within the laboratory. Performance of the Gmeter was compared with the performance of a FOSS NIRSystems Model 6500 spectrophotometer for measuring protein in soy-protein/sugar mixtures and for measuring nitrogen in fescue grass tissue. Two calibrations were developed on both instruments: (1) single-term GSD equations and (2) three-term (log 1/R) multiple linear regression (MLR) equations. Second-derivative calibration experiments on the Model 6500 spectrophotometer formulated the basis for selecting the three filters in the Gmeter. Model 6500 data indicated that the GSD calibration [coefficient of variation (CV) = 5.14%] performed better than a three-term MLR equation (CV = 8.0%). In addition, the Gmeter performed almost as well (CV = 6.30%) as the Model 6500 (CV = 5.14%) for measuring protein in the mixtures using single-term GSD equations. An exciting extra in this study was the fact that measurements from the same three filters selected for determining protein in protein/sugar mixtures could be used for determining nitrogen (CV = 17.2%) in dry-grass tissue.

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“…In this second chapter, we introduced the challenges that traceability constitutes, in brands. At the time this literature review was created, only three studies had been published on the subject (Heckman et al, 1987;Shenk et al, 1993, andWang et al, 1993 In the following chapters, we will investigate the use of commonly used standardization methods in a situation of inter-brand calibration transfer (two brands). This will help to fill the lack of literature in the comparison among standardization methods.…”

Section: Discussionmentioning

confidence: 99%

Intra and inter-brand calibration transfer for near infrared spectrometers

Igne

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Robust modeling methods were implemented for the transfer of near-infrared calibration models in intra and inter-brand situations. A network of four instruments from two brands (Foss Infratecs and Bruins OmegAnalyzerGs) was used to implement spectral pretreatment methods, local and variable selection techniques, and orthogonal methods to transfer protein, oil, and linolenic acid models across instruments of the same brand and across instruments of different brands. A total of fifty seven techniques were implemented among which spectral filtering methods based on the smoothing of high frequency components of Fourier and wavelet transforms. A new approach to local similarity was introduced. Results showed that the effectiveness of the various methods was instrument, parameter, and validation set dependent. In some situations, no differences could be observed between master and secondary unit predictions. Local methods appeared to be the weakest methods, most likely due to a problem of over-fitting (specialization) of the calibration set. The transfer of calibrations across brands was possible with performances similar, or better, than in intra-brand calibration transfer. 1 CHAPTER 1.

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Transfer of near-infrared monochromator calibrations for tobacco constituents to tilting-filter instruments

Cited by 7 publications

References 0 publications

Standardisation and Calibration Transfer for near Infrared Instruments: A Review

Standardisation and Calibration Transfer for near Infrared Instruments: A Review

Hand-Held NIR Spectrometry: Part I: An Instrument Based upon Gap-Second Derivative Theory

Intra and inter-brand calibration transfer for near infrared spectrometers

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