Techniques in accordance with the following disclosure enable digital images to be filtered (smoothed) to reduce noise and, at the same time, preserve the image's underlying structure. In general, image pixels are analyzed to identify those that participate in, or belong to, structure within the image and those that do not. For those pixels determined to be part of the image's structure, the direction of that structure is determined and filtering or smoothing along that direction is provided. Contrast enhancement in a direction perpendicular to the detected edge's direction may also be provided.