1. An inspection system comprising: an illuminator illuminating a portion of a pattern formed on a generally specular surface to be imaged, said illuminator providing at least two spectrally different and temporally spaced flashes of light, each flash of light being incident on said portion at generally the same angles of incidence; a camera arranged to receive light from said flashes and reflected by said portion of said generally specular surface to acquire at least one optical image of said portion per flash; and an image combiner operative to combine images acquired from different flashes to produce a combined image.