R. Castagno et al., A SIMPLE ALGORITHM FOR THE REDUCTION OF BLOCKING ARTIFACTS IN IMAGES AND ITS IMPLEMENTATION, IEEE transactions on consumer electronics, 44(3), 1998, pp. 1062-1070
In this paper a simple but effective operator for the reduction of blo
cking artifacts is presented, together with a simple hardware implemen
tation. The method is based on the Rational Filter approach: the opera
tor is expressed as a ratio between a linear and a polynomial function
of the input data. Such filters proved to outperform other convention
al methods in other applications, such as noise smoothing [1], thanks
to their capability of adapting gradually to the local image character
istics. The filter is capable of biasing its behaviour in order to ach
ieve good performance both in uniform areas, where linear smoothing is
needed, and in textured zones; where nonlinear and directional filter
ing is required. A detector of activity is embedded in the expression
of the operator itself so that the biasing of the behaviour of the fil
ter is smooth and not based on fixed thresholds. A solution for the ha
rdware implementation of the scheme is presented in detail. Despite th
e simplifications imposed by the hardware design, the filter retains t
he same efficiency as the original algorithm.