A fourth embodiment of the present invention is a method of generating a temperature
compensated absorbance spectrum. The method includes the steps of: a. providing
a sample spectrum and an estimated temperature of a backdrop object; b. from a
set of known temperature spectra related to a known background temperature, selecting
at least two known temperature spectra representing a background temperature above
and below the estimated temperature; c. comparing the sample spectrum to the known
temperature spectra in order to determine a sample background spectrum; and d.
calculating an absorbance spectrum from the sample spectrum and the background spectrum.
