1. A method of fluorescence imaging comprising: simultaneously acquiring image data at a plurality of phases and a plurality of frequencies from a region of interest; identifying at least one desired signal and at least one background signal in the acquired image data associated with the region of interest; constructing a digital filter based upon the at least one desired signal and the at least one background signal, wherein the digital filter is configured to enhance image contrast; and applying the digital filter to the acquired image data associated with the region of interest to enhance image contrast in the acquired image data.