STUDY OF THE EFFECT OF THE SOURCE SIZE OF INFRARED THERMOMETERS

Abstract

Noncontact temperature measurement is based on the registration by the thermal receiver of the electromagnetic radiation flux collected by the optical system of the device. Due to the imperfection of practical designs of optical systems, the receiver receives radiation from objects outside the boundaries of the nominal field of view. There is an effect of the size of the source – a change in the readings of the device when the size of the object changes. This paper is devoted to the study of the effect of the source size of reference pyrometers of the first category TRT IV.82, PD-9-02, PD-4-06. In the course of the research, a quantitative assessment of the additional measurement error that occurs when checking blackbody models using these reference pyrometers was obtained. Proposed and justified measures to minimize the resulting additional measurement error. The analysis of the effect of the source size effect on the reliability of the results of verification of blackbody models, working infrared thermometers and thermal imagers is carried out. The results of the research can be useful when conducting tests for type approval, developing methods for verification infrafred thermometers, and developing reference emitters.