1. A method of detecting at least one chemical species comprising: obtaining at least a first image from a first electromagnetic radiation detector, the first image including a first plurality of pixels, each pixel having an associated intensity value; obtaining at least a second image from a second electromagnetic radiation detector, the second image including a second plurality of pixels, each pixel having an associated intensity value; generating at least a first resultant image, the first resultant image including a plurality of resultant pixels, each pixel having an associated intensity value; determining one or more regions of interest based, at least in part, on the first resultant image; determining correlation between the first image, the second image, and the first resultant image for at least one of the one or more regions of interest using a correlation coefficient algorithm to: calculate a first correlation coefficient using the intensity values of a first subset of pixels from the first plurality of pixels and a corresponding subset of resultant pixels from the plurality of resultant pixels within at least one of the one or more regions of interest, and calculate a second correlation coefficient using the intensity values of a first subset of pixels from the second plurality of pixels and the corresponding subset of resultant pixels from the plurality of resultant pixels within the corresponding region of interest; and determining the presence of at least one chemical species based, at least in part, on the first correlation coefficient and the second correlation coefficient.