Many desirable properties make fractals a powerful mathematic
model applied in several image processing and pattern recognition tasks: image coding, segmentation, feature extraction, and indexing, just to cite some
of them. Unfortunately, they are based on a strong asymmetric scheme,
consequently suffering from very high coding times. On the other side, linear transforms are quite time balanced, allowing them to be usefully exploited in
realtime applications, but they do not provide comparable performances
with respect to the image quality for high bit rates. In this paper, we investigate different levels of embedding orthogonal linear transforms in the
fractal coding scheme. Experimental results show a clear improved quality
for compression ratios up to 15 : 1.
Combining Fractal Coding and Orthogonal Linear Transforms
