Patent ID: 7441704

Claim:
A system for identifying a spatial code applied to an object, where the spatial code includes a plurality of security tags having one or more characteristic emission spectral profiles, the system comprising: a beam source operable to illuminate said spatial code, to stimulate light emission from the security tags in the code, simultaneously from the entire code, a detector operable to record the light emission from the security tags, at each of a plurality of wavelengths, when the code is illuminated by said source, the detector further comprising (a) an image detector for recording a spatial image of light emission from the tags in the code, (b) an optical spectrometer for recording an emission profile of the tags in the code, and (c) a beam splitter for splitting emitted light from the code to both the image detector and the optical spectrometer; and a processor, coupled to the detector and the beam source, which is operable to (i) cause the beam source to illuminate said spatial code in a sequence of a plurality of time-spaced illuminations, the beam source illuminating the spatial code with a different set of illumination wavelengths for each of the plurality of time-spaced illuminations; (ii) cause the detector to record a spatial image of light emissions from the security tags in the code for each of the plurality of time-spaced illuminations; (iii) cause the optical spectrometer to record the emission profile from the security tags for each of the plurality of time-spaced illuminations; (iv) decode a time-spaced spatial code for each of the plurality of time-spaced illuminations using the spatial image of light emissions for each of the plurality of time-spaced illuminations; (v) resolve the emission spectral profiles from the security tags for each of the plurality of time-spaced illuminations to derive spectral information for each of the plurality of time-spaced illuminations therefrom, by resolving the spectrum into a plurality of wavelengths; and (vi) identify the spatial code on the basis of the combined time-spaced spatial codes and time-spaced spectral information.