Abnormal measurement detection device and method for infrared radiation thermometer

Abstract

A technique for an infrared radiation thermometer used for thermography detects measurement abnormality of the infrared radiation thermometer and estimates the causes of the measurement abnormality such as contamination of an objective lens and a malfunction in a mechanism section of the infrared radiation thermometer. The measurement abnormality detector has a dummy lensplaced in the periphery of the objective lensof the thermometerso as to be at a position and in an attitude that are more susceptible to contamination than the objective lens, a laser displacement meterfor projecting light to the dummy lensat each predetermined time or at a predetermined timing, receiving the light reflected by the dummy lens, and measuring the quantity of the received light, and determination meansfor calculating the attenuation rate of the projected light on the basis of the quantity of the received light measured by the laser displacement meter, estimating the degree of contamination of the dummy lenson the basis of the calculated attenuation rate, and judging, on the basis of the degree of contamination of the dummy lens, the necessity of warning for contamination of the objective lensand measurement abnormality of the thermometer