1. A biometric sensor comprising: a white-light illumination subsystem disposed to illuminate a purported skin site of an individual with white light; a detection subsystem disposed to receive light scattered from the purported skin site and comprising a color imager on which the received light is incident; and a computational unit interfaced with the detection subsystem and having: instructions for deriving a plurality of spatially distributed images of the purported skin site from the received light with the color imager, the plurality of spatially distributed images corresponding to different volumes of illuminated tissue of the individual; and instructions for analyzing the plurality of spatially distributed images to perform a biometric function.