Showing papers on "Lossless compression published in 1976"

Experiments in text file compression

Abstract: A system for the compression of data files, viewed as strings of characters, is presented. The method is general, and applies equally well to English, to PL/I, or to digital data. The system consists of an encoder, an analysis program, and a decoder. Two algorithms for encoding a string differ slightly from earlier proposals. The analysis program attempts to find an optimal set of codes for representing substrings of the file. Four new algorithms for this operation are described and compared. Various parameters in the algorithms are optimized to obtain a high degree of compression for sample texts.

Real-Time Video Compression Algorithm for Hadamard Transform Processing

Abstract: A real-time digital video processor using Hadamard transform techniques to reduce video bandwidth is described. The processor can be programmed with different parameters to investigate various algorithms for bandwidth compression. The processor is also adaptive in that it can select different parameter sets to trade-off spatial resolution for temporal resolution in the regions of the picture that are moving. Algorithms used in programming the system are described along with results achieved at various levels of compression. The algorithms relate to spatial compression, temporal compression, and the adaptive selection of parameter sets.

Finite-length binary phase codes for digital pulse compression

Abstract: Binary phase codes for radar pulse compression giving compression ratios greater than 13 (the maximum-length Barker code) must generally be found by trial and error on a digital computer. Formulas are derived for the maximum number of codes of given length which have different autocorrelation functions, and it is shown how redundant codes can be recognised without evaluating the autocorrelation functions.