The systematic error in digital image correlation induced by self-heating of a digital camera

The systematic strain measurement error in digital image correlation (DIC) induced by self-heating of digital CCD and CMOS cameras was extensively studied, and an experimental and data analysis procedure has been proposed and two parameters have been suggested to examine and evaluate this. Six digital cameras of four different types were tested to define the strain errors, and it was found that each camera needed between 1 and 2 h to reach a stable heat balance, with a measured temperature increase of around 10 degrees C. During the temperature increase, the virtual image expansion will cause a 70-230 mu epsilon strain error in the DIC measurement, which is large enough to be noticed in most DIC experiments and hence should be eliminated.