1. A computer-implemented method, comprising: analyzing a first image of a first set of particles having a uniform concentration of fluorescence-material associated therewith to identify one or more pixels within the first image that exhibit an optical parameter value above a first predetermined threshold; categorizing, within respective subsections of the first image, collections of pixels identified during the step of analyzing the first image; developing for each respective subsection within the first image a statistic representative of the level of the optical parameter for the collections of pixels categorized therewith; analyzing a second image of a second set of particles having an unknown concentration of fluorescence-material associated therewith to identify one or more pixels within the second image that exhibit an optical parameter value above the first predetermined threshold; separating the second image to have subsections with dimensions that are substantially equal to the subsections in the first image; categorizing, within respective subsections of the second image, collections of pixels identified during the step of analyzing the second image; and dividing the optical parameter value for each of the pixels identified during the step of analyzing the second image by the statistic developed for the corresponding first image subsection.