1. A computer-implemented digital image processing method comprising: receiving, by a processor, input data representing a blurry digital image; applying, by the processor, a variable scale filter to the blurry digital image at an original resolution to obtain a set of filtered observations at different scale levels; calculating, by the processor, an estimated blur kernel based on each of the filtered observations; and deconvolving, by the processor, the blurry digital image using the estimated blur kernel to obtain a deblurred digital image, wherein the variable scale filter includes a first filter and a second filter that is different from the first filter, and wherein the method further comprises: applying the first filter to the blurry digital image at the original resolution to obtain a first observation at a first scale level; applying the second filter to the blurry digital image at the original resolution to obtain a second observation at a second scale level that is smaller than the first scale level; calculating a first estimated blur kernel based on the first observation; calculating a second estimated blur kernel based on the second observation using the first estimated blur kernel as a baseline; and iteratively accumulating the estimated blur kernel from the first estimated blur kernel and the second estimated blur kernel.