1. A computer-implemented method comprising: filtering a digital image with an edge-preserving detail-reducing (EPDR) filter, wherein the digital image comprises a plurality of pixels; generating a first image by filtering the EPDR-filtered digital image with an image-processing filter that includes a structure-adaptive filter, wherein the structure-adaptive filter provides an intensity of a filter effect on a plurality of pixels of the EPDR-filtered digital image based on a respective geometric distance of each respective pixel of the plurality of pixels of the EPDR-filtered digital image to a reference location in the EPDR-filtered digital image, wherein the reference location is one of a reference pixel and a reference region; generating a second image by filtering the EPDR-filtered digital image with a highpass filter; and producing a third image with a suppressed noise level by adding generated the first image and generated the second image.