a comparative discrimination spectral detection system for the identification of chemicals with overlapping spectral signatures , including : a radiation source for delivering radiation to a sample ; a radiation collector for collecting radiation from the sample ; a plurality of beam splitters for splitting the radiation collected from the sample into a plurality of radiation beams ; a plurality of low - resolution optical filters for filtering the plurality of radiation beams ; a plurality of radiation detectors for detecting the plurality filtered radiation beams ; and a processor for : receiving a set of reference spectra related to a set of target chemicals and generating a set of base vectors for the set of target chemicals from the set of reference spectra , wherein the set of base vectors define a geometrical shape in a configuration space ; receiving a set of filtered test spectra from the plurality of radiation detectors and generating a set of test vectors in the configuration space from the set of filtered test spectra ; assessing a geometrical relationship of the set of test vectors and the geometrical shape defined by the set of base vectors in the configuration space ; and based on the assessed geometrical relationship , establishing a probability that a given test spectrum or spectra matches a given reference spectrum or spectra .