Systems and method for improving the quality of document images are provided. One method includes identifying a plurality of image fragments within a previously received document image that includes text. The method further includes separating the plurality of image fragments into a plurality of classes. Each class includes a subset of the plurality of image fragments that are substantially similar to one another. The method further includes, for each of the plurality of classes: (1) processing a class of image fragments to generate a combined and substantially enlarged image fragment for the class; and (2) filtering the combined and substantially enlarged image fragment to generate a filtered image fragment for the class. The method further includes generating an improved document image by replacing or modifying the image fragments within the document image based on the filtered image fragments.