An accessory for use for the inside surface and the upper edge surface of a pickup truck tailgate. Encoding produces a plurality of coded packets and a corresponding code matrix of coefficients. In another embodiment, a portable Raman spectrometer is provided. The de-duplication system identifies an area of data that incorporates the regions that should be subject to further de-duplication processing and de-duplicates this area with reference to a corresponding area within the reference data set.