166,090 research outputs found
Variable word length encoder reduces TV bandwith requirements
Adaptive variable resolution encoding technique provides an adaptive compression pseudo-random noise signal processor for reducing television bandwidth requirements. Complementary processors are required in both the transmitting and receiving systems. The pretransmission processor is analog-to-digital, while the postreception processor is digital-to-analog
Non-Adaptive Distributed Compression in Networks
In this paper, we discuss non-adaptive distributed compression of inter-node
correlated real-valued messages. To do so, we discuss the performance of
conventional packet forwarding via routing, in terms of the total network load
versus the resulting quality of service (distortion level). As a better
alternative for packet forwarding, we briefly describe our previously proposed
one-step Quantized Network Coding (QNC), and make motivating arguments on its
advantage when the appropriate marginal rates for distributed source coding are
not available at the encoder source nodes. We also derive analytic guarantees
on the resulting distortion of our one-step QNC scenario. Finally, we conclude
the paper by providing a mathematical comparison between the total network
loads of one-step QNC and conventional packet forwarding, showing a significant
reduction in the case of one-step QNC.Comment: Submitted for 2013 IEEE International Symposium on Information Theor
Better text compression from fewer lexical n-grams
Word-based context models for text compression have the capacity to outperform more simple character-based models, but are generally unattractive because of inherent problems with exponential model growth and corresponding data sparseness. These ill-effects can be mitigated in an adaptive lossless compression scheme by modelling syntactic and semantic lexical dependencies independently
Stack-run adaptive wavelet image compression
We report on the development of an adaptive wavelet image coder based on stack-run representation of the quantized coefficients. The coder works by selecting an optimal wavelet packet basis for the given image and encoding the quantization indices for significant coefficients and zero runs between coefficients using a 4-ary arithmetic coder. Due to the fact that our coder exploits the redundancies present within individual subbands, its addressing complexity is much lower than that of the wavelet zerotree coding algorithms. Experimental results show coding gains of up to 1:4dB over the benchmark wavelet coding algorithm
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