Evaluation and comparison of different
approaches to multi-product brix calibration in
near-infrared spectroscopy
Michael Kopf,
Robin Gruna,
Thomas Längle,
Jürgen Beyerer
Kapitel/Beitrag aus dem Buch: Längle, T et al. 2017. OCM 2017 – 3rd International Conference on Optical Characterization of Materials, March 22nd – 23rd, 2017, Karlsruhe, Germany : Conference Proceedings.
Near-infrared (NIR) spectroscopy became a widespread technology for qualitative and quantitative material analysis. New fields of application of this technology, e.g., quantitative food analysis for consumers, increase demand for multiproduct calibration models. Conventional multivariate calibration methods, such as partial least squares regression (PLSR),
are reported to show weakness in predictive performance [1].
Preliminary studies in multi-product calibration for quantitative
analysis of food with near-infrared spectroscopy showed good
results for memory-based learning (MBL) and a classification
prediction hierarchy (CPH) [2]. In this study, three varieties
of apples, pears and tomatoes with known °brix value are analyzed with NIR spectroscopy in the range from 900 nm to 2400
nm. Predictive performance of a linear PLSR model, two nonlinear models (CPH and MBL) and different preprocessing techniques are tested and evaluated. For error estimation, leave-oneproduct-out and leave-one-out cross-validation are used