1. A method, comprising: causing, at least in part, a substrate to be rotated to a plurality of azimuthal orientations, the substrate comprising a pattern; causing, at least in part, polarized illumination to propagate towards the substrate; causing, at least in part, polarized illumination reflected from the substrate to be detected; generating, in association with each azimuthal orientation of the plurality of azimuthal orientations, data corresponding to the detected polarized illumination; and determining asymmetry of the pattern based on the data.