Patent ID: 8897570

Claim:
A method of detecting presence of one or more target substances in an imaged scene, the method comprising: receiving a hyperspectral image comprising a spectrum of a scene pixel indicative of at least a portion or light and other radiation absorbed by, or emitted from, a location of the imaged scene corresponding to the scene pixel; applying a whitening transform to the spectrum of the scene pixel; determining, for the whitened spectrum, one or more mixture coefficients for target spectrum of the one or more target substances, wherein a product of the one or more mixture coefficients and the target spectrum represents an estimate of an abundance of the one or more target substances at the location corresponding to the scene pixel; determining, for the whitened spectrum, a residual spectrum, wherein the residual spectrum includes one or more quantitative values indicative of a portion of the whitened spectrum not in the estimate of the presence of the one or more target substances; and detecting the presence of the one or more target substances at the location based on the one or more mixture coefficients and the residual spectrum, including forming a ratio of a measure of spectral match based on the mixture coefficients and a measure of spectral unmatch based on the residual spectrum, the ratio being indicative of presence of the at least one target substance at the location.