Modeling of systematic errors in stereo-digital image correlation due to camera self-heating.

Area of Science:

• Optical Measurement Techniques
• Experimental Mechanics
• Image Processing

Background:

• Camera self-heating is a known source of error in stereo-digital image correlation (stereo-DIC).
• These thermal errors can significantly compromise measurement accuracy and vary between system configurations.
• The underlying mechanism and dependence on camera parameters remain unclear.

Purpose of the Study:

• To elucidate the mechanism by which camera self-heating introduces artifacts in stereo-DIC strain measurements.
• To theoretically model and quantify thermal errors in 3D coordinate reconstruction and deformation measurements.
• To investigate the influence of camera parameters on these thermal errors.

Main Methods:

• Detailed explanation of thermal artifact generation in stereo-DIC.
• Development of a simplified stereovision model to derive theoretical error equations.
• Simulations to analyze the effect of self-heating and camera parameters on measurements.
• Experimental validation using a smartphone-based stereo-DIC system.

Main Results:

• Theoretical framework established for thermal error in 3D coordinate, displacement, and strain measurements.
• Simulations demonstrated the impact of camera self-heating and parameters on measurement accuracy.
• Experimental tests confirmed the validity of the theoretical analysis and simulation outcomes.

Conclusions:

• Camera self-heating is a critical factor affecting stereo-DIC accuracy, particularly in 3D deformation analysis.
• The developed theoretical model and simulations provide a basis for understanding and mitigating thermal errors.
• Findings are validated by experimental results, emphasizing the need to account for thermal effects in stereo-DIC systems.