Method for the contactless measuring of temperature with a multi-channel pyrometer

Claim 1

In a method for the contactless measurement of the temperature of an object with a plurality of surface components a i having i=1 to m differently emitting surface materials at the same temperature, including measuring the spectral signal voltages of a black body with a multi-channel pyrometer at j=1 to n spectral channels at a plurality of different temperatures to determine the characteristic curve of the relationship between the difference between the spectral signal voltages U oj -U uj and the temperature of the black body at a plurality of various temperatures of the black body, and storing characteristic data corresponding to said curve, where m and n are integers, U oj is the portion of the signal voltage difference U oj -U uj which depends upon the temperature T o of the black body, and U uj is the portion thereof which depends upon the known ambient temperature, the improvement wherein said method further comprises: calibrating the pyrometer by measuring the signal voltages U ij of m known surface materials therewith at a known temperature, for each combinaion of i=1 to m surface materials and j=1 to n spectral channels, and calculating and storing the emissivities ε ij specific to said known the surface materials in accordance with the equation: ##EQU3## using the measured values of U ij and said stored calibration data corresponding to the black body at said known respective temperature for the difference signal U oj -U uj ; measuring signal voltages U j from the object to be measured, in each of the j=1 to n spectral channels; and determining the object temperature of the body by successively inserting into the equation: U.sub.j =(a.sub.1 ε.sub.1j +a.sub.2 ε.sub.2j + . . . +a.sub.m ε.sub.mj)(U.sub.oj -U.sub.uj) the differences U oj -U uj from the stored calibrated data at each of a plurality of temperatures, as well as the stored emissivities ε ij , where the sum of all the surface components a i =1 and U j are the signal voltages measured from the object, whereby the temperature of the object to be measured is the temperature corresponding to the stored calibration data which results in a solution to the last mentioned equation.