ABSTRACT
Group theory and linear algebra are used to develop a quantitative measure of the deviation from ideal symmetry in a CBED pattern. The pattern is represented as a function vector, where projection operators are used to construct maps of the orthogonal irreducible representations, and the centre is defined as the position which maximises the norm of the identity representation. In typical patterns, errors of 5% are observed, attributed to a combination of specimen strain and distortions in the electron optics.
