1,721,160 research outputs found
Proceedings of the First International Conference on Data Compression, Communications and Processing (CCP2011)
No full textDictionary Based Compression for Images
No full textAbstract
—
Lempel-Ziv methods were original introduced to
compress one-dimensional data (text, object codes, etc.) but recently
they have been successfully used in image compression.
Constantinescu and Storer in [6] introduced a single-pass vector
quantization algorithm that, with no training or previous knowledge
of the digital data was able to achieve better compression results with
respect to the JPEG standard and had also important computational
advantages.
We review some of our recent work on LZ-based, single pass,
adaptive algorithms for the compression of digital images, taking into
account the theoretical optimality of these approach, and we
experimentally analyze the behavior of this algorithm with respect to
the local dictionary size and with respect to the compression of bi-
level image
Interactive compression of books
No full textIn this paper we study interactive data compression and present experimental results on the
interactive compression of textual data (books or electronic newspapers) in Italian or English language.
The main intuition is that when we have already compressed a large number of similar texts in the past, then we
can use this previous knowledge of the emitting source to increase the compression of the current text and we
can design algorithms that efficiently compress and decompress given this previous knowledge. By doing this
in the fundamental source coding theorem we substitute entropy with conditional entropy and we have a new
theoretical limit that allows for better compression. Moreover, if we assume the possibility of interaction
between the compressor and the decompressor then we can exploit the previous knowledge they have of the
source. The price we pay is a very low possibility of communication errors
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