Abstract Humans have an innate ability to perceive symmetry, but it is not obvious how to automate this powerful insight. Following automatic classification of the pattern's symmetry group, knowledge of the interplay between rotation, reflection, glide-reflection and translation in that group leads to a small set of candidate motifs that exhibit local symmetry consistent with the global symmetry of the entire pattern. Although other work has addressed detection of the translational lattice of a repeated pattern, ours is the first to seek a principled method for determining a representative motif.
Experiments show that the resulting pattern motifs conform well with human perception.