MODIFIED ALGORITHM FOR STANDARDIZATION OF NEAR-INFRARED SPECTROMETRICINSTRUMENTS

The transfer of calibration models between near-infrared spectrometric instruments with the algorithm proposed by Shenk and Westerhaus as a standardization method is studied. This algorithm does not yield optim al results when standardization samples are used that are not of the s ame nature as the samples to be analyzed. In an attempt to improve the results obtained with this algorithm when one uses such standardizati on samples, five different modifications of the spectral intensity cor rection step of the algorithm are investigated. The use of locally wei ghted regression, which gives more weight to the standardization sampl es close to the same spectral intensity range where the samples to be predicted are located and less weight to the farthest samples, seems t o be the most suitable one.