Oil-matching by using a simple vector model for fluorescence spectra.

A digitized fluorescence spectrum containing n points may be considered as a vector in n-dimensional space. This concept is used to develop a vector model employing angular distance in n-space as parameter for comparison of fluorescence spectra of weathered oil. The vector model is applied to the problem of forensic oil-identification, by comparing the spectra of oil-spill samples with the spectra of unweathered and laboratory-weathered oils through likely suspects. The vector representing the oil-spill spectrum is projected on the hyperlane formed by the spectra of the unweathered and corresponding laboratory-weathered oils to locate the vector which has the smallest angular deviation from the spill vector ("best fit").