The invention provides a method of obtaining data cubes such that elimination of the irrelevant portion of the illumination reveals the low intensity intrinsic spectral components. The method obtains target and reference data cubes using a single camera and of a single field of view so that low-level intrinsic spectral components may be detected and enhanced under conditions of high illumination intensity without the use of filters. Two exposures in rapid succession of the same field of view at the same camera settings are taken, one exposure of the target is taken under coherent conditions where the field of view is in focus, and the second exposure is of the same field of view taken under non-coherent conditions where the target is defocused such that it has no discernible spatial features in the field of view. Residual spectra previously determined is added to the defocus spectra in the defocus data cube of the target of interest resulting in an adjusted reference spectra, which in turn is subtracted from the corresponding focused spectra in the focused data cube of the target of interest resulting in a focused target data cube each of whose pixels is associated with its intrinsic spectrum.