A Simple Postprocessing Technique for the Reduction of Blocking Artifacts
Nam Ik Cho, Bong Gyun Roh, Sang Uk Lee · Journal of Electrical Engineering and Information Science · 1999
This paper proposes an algorithm for the reduction of blocking artifacts in the transform coded images and videos. The algorithm is based on the filtering of block boundaries. However, the proposed technique is not the actual filtering in the sense that no multiplication of the pixel values with the filter coefficients is required. Instead of filtering the pixel values through the filter coefficients, the output of the filter is modeled as a typical step response function of the lowpass filter or functions with similar shapes. The blocky signal is just replaced by the modeled output signal which is generated by the library function such as exp or sin, where the magnitude and time constant for exp or frequency for sin depend on the shape of the input. The algorithm can easily be implemented by a small size look-up-table that stores the outputs of library functions. It is shown that the objective and subjective performance is comparable to or better than those of other algorithms based on the conventional filtering and POCS (projection onto convex sets).