JPS6412235A - Radiation thermometer - Google Patents

Abstract

PURPOSE:To enable selection of true solution, by using three wavelengths of light to be projected to an object to be measured and providing a learning function (function of storing and comparing sets of previous measured value and true temperature). CONSTITUTION:Light containing three wavelengths lambda1-lambda3 is projected to an object TG with the passage of light from a generation light source L through a chopper CP and the reflected light thereof passes through a lens LS, a fiber FG and filters F1'-F3' so that lights with the wavelengths lambda1-lambda3 are incident into photo detectors S1'-S3'. Detection signals thereof are applied to amplifiers 1'-3' and intensity signals R(lambda1)-R(lambda3) of the reflected lights are inputted into a reflection factor comparative computation means RC. On the other hand, the light of the light source L is passed through filters F1-F3 to be incident into detectors S1-S3, the intensity signal of a component light is inputted into the RC and a 2-wavelength reflection factor ratio of the TG is computed to be inputted into a temperature computation means TC, which stores temperature values coinciding with each other among those determined in the combination of two wavelengths temporarily as true temperature. When several temperatures can not be determined to be a true temperature, they are compared with memory values obtained in the previous measurements to determine a true temperature, which is displayed DS.