Method to eliminate thermal disturbance errors in digital image correlation measurement based on projection speckle

Area of Science:

• Materials Science
• Optical Measurement
• Metrology

Background:

• Digital image correlation (DIC) is a vital optical technique for measuring material strain and displacement.
• High-temperature applications of DIC are increasingly common but suffer from significant thermal disturbance errors.
• Existing methods struggle to accurately compensate for thermal effects in DIC measurements.

Purpose of the Study:

• To develop and validate a new method for eliminating thermal disturbance in DIC measurements.
• To improve the accuracy of strain and displacement analysis in high-temperature environments.
• To enable reliable DIC measurements under challenging thermal conditions.

Main Methods:

• A projection speckle method was employed, applying distinct color information to the test piece surface.
• A color camera captured images, with channels separated for each frame.
• DIC calculations were performed on separated channels to isolate and remove thermal disturbance errors.

Main Results:

• The proposed method successfully separated real displacement from thermal disturbance.
• Experimental validation showed high consistency between corrected DIC results and true stage displacement.
• The feasibility and accuracy of the thermal disturbance elimination technique were confirmed.

Conclusions:

• The projection speckle method effectively eliminates thermal disturbance in DIC measurements.
• This technique significantly enhances the accuracy of high-temperature material analysis.
• The findings pave the way for more reliable DIC applications in extreme thermal environments.