An image processing apparatus for processing a digital image, the digital image comprising a reference block and one or more further blocks, wherein the processing is non-local denoising of the digital image based on the reference block and the one or more further blocks, the image processing apparatus comprising: a determiner being configured to determine one or more similarity measures between the reference block and the one or more further blocks, wherein each similarity measure indicates a similarity between a noise distribution in the reference block and a noise distribution in a further block of the one or more further blocks, the determiner being further configured to determine one or more similar blocks from the one or more further blocks upon the basis of the one or more similarity measures; wherein each similarity measure further indicates a similarity between an intensity distribution in the reference block and an intensity distribution in the further block of the one or more further blocks; wherein the determiner is configured to determine a reference noise indicator indicating the noise distribution in the reference block, to determine one or more further noise indicators indicating the noise distributions in the one or more further blocks, and to combine the reference noise indicator with the one or more further noise indicators to determine the one or more similarity measures between the reference block and the one or more further blocks; wherein the determiner is configured to determine a reference image feature measure, in particular an average intensity, of the reference block, to determine one or more further image feature measures, in particular average intensities, of the one or more further blocks, to determine the reference noise indicator upon the basis of the reference image feature measure, and to determine the one or more further noise indicators upon the basis of the one or more further image feature measures; wherein the apparatus further comprises a memory, wherein the memory is configured to store one or more stored image feature measures and one or more stored noise indicators, wherein each stored image feature measure is associated with a stored noise indicator, and wherein the determiner is configured to compare the reference image feature measure or a further image feature measure with the one or more stored image feature measures in the memory, and to retrieve a stored noise indicator from the memory being associated with a stored image feature measure corresponding to the reference image feature measure or the further image feature measure. a determiner being configured to determine one or more similarity measures between the reference block and the one or more further blocks, wherein each similarity measure indicates a similarity between a noise distribution in the reference block and a noise distribution in a further block of the one or more further blocks, the determiner being further configured to determine one or more similar blocks from the one or more further blocks upon the basis of the one or more similarity measures; wherein each similarity measure further indicates a similarity between an intensity distribution in the reference block and an intensity distribution in the further block of the one or more further blocks; wherein the determiner is configured to determine a reference noise indicator indicating the noise distribution in the reference block, to determine one or more further noise indicators indicating the noise distributions in the one or more further blocks, and to combine the reference noise indicator with the one or more further noise indicators to determine the one or more similarity measures between the reference block and the one or more further blocks; wherein the determiner is configured to determine a reference image feature measure, in particular an average intensity, of the reference block, to determine one or more further image feature measures, in particular average intensities, of the one or more further blocks, to determine the reference noise indicator upon the basis of the reference image feature measure, and to determine the one or more further noise indicators upon the basis of the one or more further image feature measures; wherein the apparatus further comprises a memory, wherein the memory is configured to store one or more stored image feature measures and one or more stored noise indicators, wherein each stored image feature measure is associated with a stored noise indicator, and wherein the determiner is configured to compare the reference image feature measure or a further image feature measure with the one or more stored image feature measures in the memory, and to retrieve a stored noise indicator from the memory being associated with a stored image feature measure corresponding to the reference image feature measure or the further image feature measure.