Comparison of two methods for determination of crystal orientation using two Kikuchi pairs in electron diffraction patterns

Kikuchi diffraction pattern analysis is one of the essential techniques of transmission electron microscopy used in materials science. For instance, one important application is its use in crystal orientation determination. During the development of SAKI5 software for the simulation and analysis of Kikuchi patterns, two methods in the literature for crystal orientation determination from two independent Kikuchi pairs have been revisited and then implemented. This paper compares the formula derivations of these two methods, revealing their geometrical connections in terms of the optical path. The discussion is beneficial for electron microscopy researchers and students seeking insights into this research domain. A brief overview of a newly added module in SAKI5 software using these two methods is also provided, accompanied by a detailed example. Computational results indicate that better outcomes can be achieved by utilizing the average of both methods.