1. A method, comprising: applying an image denoising technique to an image patch of a noisy image to generate a modified image patch; determining, from partitions of example image patches that are sampled from example images, a closest partition center patch to the modified image patch, the example image patches in a partition being similar, one example image patch to another, and including a partition center patch that is determined to represent the example image patches of the partition; classifying the image patch of the noisy image as a common patch or as a complex patch of the noisy image, said classifying based on a distance between the modified image patch and the closest partition center patch; and applying a denoising operator to the image patch based on the classification.