Abstract:
Visual Cryptographic methods are not sufficient to solve all image
security related issues. Watermarking is the art of hiding secret image in ways
that prevent the detection of hidden images. Multimedia documents are very
easy to copy and distribute in an illicit manner. Copyright labelling is a process
that may help to reduce their illicit copying. If this document is copied the copy
will also contain the label. This label (or watermark) should be robust enough to
withstand normal image processing activities (like image compression,
transforming to different format) that do not significantly alter the image
appearance. In fractal image compression the encoding step is computationally
expensive, because every range block must be compared to all domain blocks in
the codebook to find the best-matched one during the coding procedure.
In this paper, a fast fractal encoding algorithm is proposed. Simulation
results show that the runtime of the proposed algorithm is reduced greatly
compared to the existing methods. At the same time, the new algorithm also
achieved high compression ratio.
