This paper deals with an analysis of the directional reflectance curve s specified by 2 kinds of independent variables, ie. wavelength and spatial direction.
Generally, these reflectance curves have been analyzed for each of spatial directions successively, and it was suspected that this usual method was ineffective for utilization of informations contained in these observations.
The principle of the present method is based upon the effective combination of principal component analysis and regression analysis, both of which are frequently used in multivariate statistics.
The following effectiveness were confirmed by comparing true, observed and estimated spectral reflectance curves in a model experiment:
(1) There is a possibility to make a useful estimation of physical meanings which might be hidden behind observed raw data.
(2) The estimated spectral reflectance curves by the present method give better fit to the true curves than the raw data.