A combined hardware and software method for the projection center calibration of the diffraction pattern

Area of Science:

• Materials Science
• Crystallography
• Computational Science

Background:

• Precise projection center (PC) coordinates are crucial for electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD).
• Existing PC calibration methods involve hardware maneuvers or software algorithms, each with limitations like uncertainties and biases.
• There is a need for improved PC calibration techniques that combine accuracy and reliability.

Purpose of the Study:

• To introduce a novel hybrid method for accurate PC calibration in EBSD and TKD.
• To combine the strengths of hardware (moving screen) and software (image correlation) calibration techniques.
• To validate the efficiency and reliability of the proposed method in EBSD practices.

Main Methods:

• Acquiring multiple diffraction patterns from the same sample area at varying detector positions.
• Utilizing an integrated digital image correlation framework (IDIC-M) with a simulated master pattern.
• Employing a hybrid approach associating moving screen image correlation for PC calibration.

Main Results:

• The hybrid method significantly improves PC calibration precision by 74.0% over pure hardware methods and 21.8% over pure software methods.
• The method successfully relates different diffraction patterns to determine unique crystal orientation and varying PC values.
• Validation confirms the gradient-based pattern correlation is free of systematic errors, proving efficient and reliable.

Conclusions:

• The proposed hybrid PC calibration method offers superior precision and reliability for EBSD and TKD.
• This technique effectively overcomes the limitations of existing standalone hardware and software calibration approaches.
• The validated method is a valuable tool for enhancing the accuracy of diffraction analysis in materials science.