1. A land-based vehicle including an arrangement for monitoring objects in or about the vehicle, comprising: a source from which illumination is emitted into an area in or about the vehicle; a receiver arranged to receive illumination reflected from an object in the path of the illumination; a light-regulating component arranged in front of said receiver to regulate reception of illumination by said receiver, said light-regulating component being modulated to enable a determination of a distance between an object from which the illumination has been reflected and said receiver; and circuitry coupled to said source, said receiver and said light-regulating component and arranged to obtain information about objects from which the received illumination has been reflected other than distance information and associate with the objects distances between the objects and said receiver.