Error analysis of strain measurement induced by operating temperature of uncooled CCD

Abstract

This paper focuses on the effect of operating temperature of uncooled CCD on the strain measurement error when the CCD is used to measure strain in an optical extensometer. A special experiment is designed in which an optical extensometer is used to measure the strain and a thermocouple is used to measure the temperature of CCD. The results show that the measured temperature of CCD has a similar tendency with the change of the measured strain. For different types of uncooled CCD, the temperature varies about 5~10 degree from the beginning of the experiment to the end, and the error of the measured strain induced by the temperature was about 120~180με. It is considered that the error is related to the inherent noise of the electronic components of the CCD whose operating mode is sensitive to the temperature change. When using the optical extensometer, it is suggested to preheat the CCD 1~2 hours before the experiment especially in doing high accuracy measurement. Otherwise, the strain induced by the operating temperature should be eliminated from the measurement results through conducting temperature compensation method mentioned in this paper.