Directional deringing filters

Systems and methods are described for removing ringing artifacts from a coded image. For each block of coded image data, a direction is identified by selecting a directional block divided into a plurality of pixel lines in one predetermined direction of a set of at least four predetermined directions. The directional block may have a constant value across each pixel line. A parameter related to a sum of a mean-square difference between a pixel value and the pixel average of pixels falling on a pixel line in the directional block that includes the location of the pixel may be calculated for each direction of the set. The direction of the set having a minimum summed mean-square difference is selected as the direction for the block based on the calculated parameter values. A non-linear filter is then applied to each block based on the identified direction for the block.