1. A method for enhancing contrast in fluorescence imaging, comprising: providing a patterned illumination source for illuminating one or more regions corresponding to a scan step; scanning at least a portion of a surface of a subject using a plurality of scan steps; acquiring image frames corresponding to two or more scan steps; deducting a background fluorescence from the image frames corresponding to the two or more scan steps to form one or more processed image frames; and reconstructing an image using one or more of the processed image frames.