1. Apparatus for determining a signature from an article arranged in a reading volume comprising: a generator operable to generate and sequentially direct a focussed noncoherent beam onto each of a plurality of different regions of the reading volume; a detector arrangement operable to collect a set comprising groups of data points, wherein each group of data points is collected from signals obtained when the beam scatters from the different regions of the reading volume, such that each of the different ones of the groups of data points relates to scatter from each of the respective different regions of the reading volume; and a data acquisition and processing module operable to determine a signature of the article from the set of groups of data points.