The invention relates to an illumination system comprising at least one beam path with means for simultaneously illuminating the test object within at least one reference wavelength range and at least one data wavelength range, each of which is coordinated with one respective color channel of an imaging recording system. The at least one data wavelength range is used for detecting a medically relevant piece of information while the at least one reference wavelength range is at least nearly invariant in relation to said medically relevant piece of information. The inventive method combines the image values of evaluation windows or individual pixels of simultaneously recorded images into secondary images and image sequences while generating location-resolved dynamic characteristic values which are combined into function images.
