The Prediction of the Yield of Wool by Near-Infrared ReHectance Spectroscopy

Abstract

The prediction of wool base of greasy wool in the form of miniature cores from digitized near-infrared reflectance spectra is demonstrated. This secondary calibra tion method combines measurements of reflectance at several wavelengths in a multiple linear regression equation for a prediction of wool base. A variety of methods of selecting suitable wavelengths for prediction was employed. Suitable wavelengths could not be selected from considering the spectra of the components, or from the statistical properties of the spectral data. A combination of an exhaustive search and the forward stepwise addition method applied over the spectral range gave the best selection of wavelengths. For the population of 42 samples studied, the error of the calibration is similar in magnitude to that of the conventional gravimetric test.

Get full access to this article

View all access options for this article.

References

Andrews, M.W. , Connell, J.P. , David, H.G. , Marler, J.W. , and O'Donnell, R.E. , "Predicting Wool Yield by Diffuse Reflectance Spectroscopy. Part 2. Greasy Wool," Proc. IWTO Tech. Cttee, Munich, Report No. 3, June 1978.

A.S.T.M., "Wool Content of Raw Wool-Laboratory Scale," Designation D-584-77, 1977.

Buckenham, P. , Dehlsen, A.B. , and David, H.G. , The Mini-Coring Technique as a Method of Subsampling Wool, Textile Inst. Ind. 17, 244-245 (1979).

Connell, J.P. and Norris, K.H. , The Prediction of the Yield of Greasy Wool by Near Infrared Reflectance Spectroscopy. Part I: Principles and Washed Wool, Textile Res. J. 50, 371-380 ( 1980).

I.W.T.O., "Determinations of Wool Base, Vegetable Matter Base, 'IWTO Clean Wool Content', and 'IWTO Scoured Yield' in Raw Wool," Specifications of Test Methods, IWTO-19-76(E).

Miller, A.J. , "Selecting Subsets of Regressor Variables," Symposium on Regression Analysis of the New South Wales Branch of the Statistical Society of Australia, Paper 1, August, 1979.

Sabbagh, H.R. and Larsen, S.A. , Wool Yield by Infrared Reflectance Analysis, Proc. Am. Soc. Anim. Sci., (Western Section) 29, 108-109 ( 1978).

Scott, R.F. and Roberts, E.M. , Objective Measurement of Clean Fleece Weight by Infrared Reflectance Spectroscopy , Wool Technol. Sheep Breed. 26 (2), 27-30 (1978).