A consistent full-field integrated DIC framework for HR-EBSD

A general, transparent, finite-strain Integrated Digital Image Correlation (IDIC) framework for high angular resolution EBSD (HR-EBSD) is proposed, and implemented through a rigorous derivation of the optimization scheme starting from the fundamental brightness conservation equation in combination with a clear geometric model of the Electron BackScatter Pattern (EBSP) formation. This results in a direct one-step correlation of the full field-of-view of EBSPs, which is validated here on dynamically simulated patterns. Strain and rotation component errors are, on average, (well) below 10−5 for small (Eeq=0.05%) and medium (Eeq=0.2%) strain, and below 3×10−5 for large strain (Eeq=1%), all for large rotations up to 10° and 2% image noise. High robustness against poor initial guesses (1° misorientation and zero strain) and typical convergence in 5 iterations is consistently observed for, respectively, image noise up to 20% and 5%. This high accuracy and robustness rivals, when comparing validation on dynamically simulated patterns, the most accurate HR-EBSD algorithms currently available which combine sophisticated filtering and remapping strategies with an indirect two-step correlation approach of local subset ROIs. The proposed general IDIC/HR-EBSD framework lays the foundation for future extensions towards more accurate EBSP formation models or even absolute HR-EBSD.