| Abstract |
Fractal image compression is a block based technique. The blocks
of the underlying image partition are called range blocks. Like all
block based techniques, fractal coding suffers from blocking artifacts,
in particular at high compression ratios. Moreover, due to the
recursive nature of the fractal decoder blocking artifacts also show
up in the interior of the range blocks. This paper proposes an effective
post-processing to reduce both kinds of these artifacts. We
apply a smoothing filter adapted to the partition before each iteration
of the decoding process which reduces the blocking artifacts in
the interior of the range blocks. After decoding the reconstructed
image is enhanced by applying another adaptive filter along the
range block boundaries. This filter is designed to reduce blocking
artifacts while maintaining edges and texture of the original image.
The experimental results show that the artifacts are reduced and
significant improvements can be achieved. Our method compares
favourably with previously published post-processing techniques
for fractal image compression. |