Abstract

Journal of Near Infrared Spectroscopy
Volume 16 Issue 3, Pages 311–315 (2008)
doi: 10.1255/jnirs.793

Removing the block effects in calibration by means of dynamic orthogonal projection. Application to the year effect correction for wheat protein prediction

Jean-Michel Roger,a,* Fabien Chauchardb and Phil Williamsc
aInformation and Technologies for Agro-processes–Cemagref, BP 5095, 34033 Montpellier Cedex 1, France
bOndalys, SARL, Parc Minea–Cemagref, BP 5095, 34033 Montpellier Cedex 1, France
cPDK Projects, Inc., 5072 Vista View Crescent, Nanaimo, British Columbia, Canada V9V 1L6

NIR spectroscopic models lack robustness towards the infuence of external parameters. Orthogonalisation techniques have demonstrated their ability to improve model robustness with regard to external parameter effects. The dynamic orthogonal projection (DOP) method is applied to the correction of the growing season effect on wheat protein content prediction using NIR spectroscopy. A few reference samples are measured at the beginning of each harvest. For each one, DOP generates an“ideal spectrum” by applying a reference-centred linear kernel on the calibration database. The parasitic sub-space, spanned by the differences between ideal and measured spectra, is then removed from the calibration space, by means of an orthogonal projection. The application database covered eight years of wheat NIR spectra related to protein content. The first four years were used for calibration and the remaining years for testing. The corrections were calculated using the first scanned samples of every year, for each variety [between five and ten samples (four samples per year)]. Results were compared with standard partial least squares calibration models.

Keywords: orthogonal correction, robust calibration, PLS, external parameter influence correction

Full-text article (429 kB) (subscribers only)

Buy article on-line for £113.75 (get immediate access)

Alerting Service

 RSS Feed

Permalink: http://dx.doi.org/10.1255/jnirs.793
QR Code (what is this?):

Alerting Services

Our Table of Contents Alerting Service will keep you up-to-date with the latest research published in our journals.

You can also follow our journals on Twitter or subscribe to their RSS feeds.  Follow us on Twitter and Subscribe to our RSS Feeds

Sign Up Now

Subscriptions

Discover the benefits of subscribing to our periodicals

  • Quality Science
  • Fair Pricing
  • Important Research
  • Flexible Subscriptions

Subscribe Today

New Books

New Series of Focused Books in Print and E-Reader Formats

Design of Experiments“If you’re going to experiment, then it is always worth doing it properly” writes Tom Fearn in this introduction to Design of Experiments.
find out more

Near Infrared Spectroscopy on Agricultural HarvestersThis book provides an overview of the deployment of NIR analysers onto harvesting machinery to give real-time, point-of-cropping data.
find out more

Sample Copy of JNIRS