1. A method of determining emissivity, temperature and area of an object, the method comprising: simulating a measure of a radiant intensity of the object at each of a first wavelength, a second wavelength and a third wavelength; forming a plurality of ratios of the measures of radiant intensity of the object, wherein each ratio is based upon a relationship of the measure of radiant intensity of the object at one wavelength to the measure of radiant intensity of the object at another wavelength; determining the emissivity of the object as a function of the temperature of the object for each of a plurality of the ratios; determining the area of the object as a function of the temperature of the object for each of a plurality of the ratios based upon the emissivity of the object as determined for a respective ratio and the measure of radiant intensity of the object at a wavelength other than the wavelengths associated with the respective ratio; and determining the temperature of the object based upon the measure of radiant intensity of the object at each of the first, second and third wavelengths and the emissivity and the area of the object as determined as a function of the temperature of the object wherein determining the emissivity, area and temperature of the object is performed by a processor.