Showing papers on "Data compression published in 1971"
Book•
01 Jan 1971
1,377 citations
TL;DR: An adaptive variable length coding system is presented, developed primarily for the proposed Grand Tour missions, but many features of this system clearly indicate a much wider applicability.
Abstract: An adaptive variable length coding system is presented Although developed primarily for the proposed Grand Tour missions, many features of this system clearly indicate a much wider applicability Using sample to sample prediction, the coding system produces output rates within 025 bit/picture element (pixel) of the onedimensional difference entropy for entropy values ranging from 0 to 8 bit/pixel This is accomplished without the necessity of storing any code words Performance improvements of 05 bit/pixel can be simply achieved by utilizing previous line correlation A Basic Compressor, using concatenated codes, adapts to rapid changes in source statistics by automatically selecting one of three codes to use for each block of 21 pixels The system adapts to less frequent, but more dramatic, changes in source statistics by adjusting the mode in which the Basic Compressor operates on a line-to-line basis Furthermore, the compression system is independent of the quantization requirements of the pulse-code modulation system
185 citations
TL;DR: Published papers and reports dealing with data compression, picture properties and models, picture coding and transmission, image enhancement, and human visual information processing are listed.
Abstract: Published papers and reports dealing with data compression, picture properties and models, picture coding and transmission, image enhancement, and human visual information processing are listed.
37 citations
01 Jan 1971
TL;DR: One suboptimum filtering scheme is derived which yields virtually the same performance as optimum filters and has the practical advantage that the filter transfer characteristics are independent of noise n(t) in many cases of interest.
26 citations
Patent•
10 Dec 1971TL;DR: In this paper, data signals are progressively combined to form successively decreasing numbers of groups of combined signals until a single group of signals is obtained, which are then selectively transmitted and decoded.
Abstract: Data compression methods and the apparatus therefor are provided in accordance with the teachings of the present invention. According to one embodiment of this invention data signals are progressively combined to form successively decreasing numbers of groups of combined signals until a single group of signals is obtained. Those groups of combined signals containing nonredundant information are selectively transmitted. The selectively transmitted groups of combined signals are received and decoded whereby original data signals are regenerated. The data signals may comprise a multibit digital word or may represent video information. Encoding of the data signals removes redundant portions therefrom.
21 citations
01 Jan 1971
TL;DR: Some effects of data compression and random noise on multispectral data, particularly as they apply to pattern recognition and picture quality are presented.
Abstract: Two problem areas are often encountered in the use of multispectral scanner data: (1) large quantities of man and machine time are required to analyze and store the volumes of data gathered and (2) the quality of the data is usually reduced by the introduction of unwanted random noise. This paper will present some effects of data compression and random noise on multispectral data, particularly as they apply to pattern recognition and picture quality.
13 citations
TL;DR: The best of a dozen different methods for compressing map data is illustrated, generated by encoding data strings—sequence of like codes—by three methods and in four directions.
Abstract: The best of a dozen different methods for compressing map data is illustrated. The choices are generated by encoding data strings—sequence of like codes—by three methods and in four directions. Relationships are developed between compression alternatives to avoid comparing all of them. The technique has been used to compress data from forest resource maps, but is widely applicable to map and photographic data reduction.
12 citations
01 Apr 1971
TL;DR: The application of compact coding, differencing and other techniques to indexed sequential files is discussed, the effects on system performance are discussed and reductions of almost 80% in mass storage requirements for a particular file are reported.
Abstract: The application of compact coding, differencing and other techniques to indexed sequential files is discussed. The effects on system performance are discussed and reductions of almost 80% in mass storage requirements for a particular file are reported.
8 citations
5 citations
TL;DR: In this article, two transform techniques, the Hadamard-Walsh transform and the eigenvector expansion technique, were used for image analysis by transform methods, and experimental results were shown in terms of the degree of imagery data compression that can be obtained for each method.
Abstract: This paper presents some new results on the subject of imagery analysis by transform methods. Two transform techniques are presented. The first is the Hadamard-Walsh transform and the second is an eigenvector expansion technique. Experimental results are shown in terms of the degree of imagery data compression that can be obtained for each method. Results are also presented from a simulation experiment of picture transmission in a noisy environment.
01 Dec 1971
TL;DR: It is shown theoretically that under certain conditions one can preprocess the raw measurement data such that the loss of information is minimized and the estimation performance is practically the same as when no data compression is utilized.
Abstract: This paper deals with the compression of the data obtained from measurements in real-tome non-linear estimation problems. The purpose is to reduce the data processing requirements. Since data compression is never optimal, one always can expect a certain deterioration in the performance of the estimator when using the compressed data. However, it is shown theoretically that under certain conditions one can preprocess the raw measurement data such that the loss of information (in the sense of Fisher) is minimized. In this case, the estimation performance is practically the same as when no data compression is utilized. A specific application, the tracking of a reentry vehicle with a linearized filter, is discussed in more detail and simulation results are presented. The conditions derived theoretically are satisfied in this case and the results confirm this.
01 Oct 1971
TL;DR: A simple time-tag data-compression scheme which uses a binary nonconsecutive one code to provide higher data compression ratios than similar schemes which have been suggested.
Abstract: A simple time-tag data-compression scheme which uses a binary nonconsecutive one code is introduced to provide higher data compression ratios than similar schemes which have been suggested. This data-compression scheme should be very easy to implement. In addition, it does not require a priori knowledge of the information source.
Proceedings Article•
01 Jan 1971
TL;DR: PCM TV photographic data communication for grand tour of outer planets, emphasizing adaptive information-preserving data compression system for optimal performance as discussed by the authors, which is based on adaptive information preserving data compression.
Abstract: PCM TV photographic data communication for grand tour of outer planets, emphasizing adaptive information-preserving data compression system for optimal performance
01 Feb 1971
TL;DR: This document is a comprehensive bibliographic research of the literature concerning the subjects of data compression, data compaction, data reduction in communications, telemetry, and data processing applications.
Abstract: : The document contains a comprehensive bibliographic research of the literature concerning the subjects of data compression, data compaction, data reduction in communications, telemetry, and data processing applications. Each reference is briefly abstracted. (Author)
01 May 1971
TL;DR: Data compression techniques for space flight data transmission systems using Telemetry Redundancy Analyzer shows good results in terms of compression and efficiency.
Abstract: Data compression techniques for space flight data transmission systems using Telemetry Redundancy Analyzer
IBM1
TL;DR: The principle of a system for video bandwidth compression by multiplexing was described in [1] and that scheme was applied to two-level images and a bandwidth compression of 2.6 was achieved.
Abstract: The principle of a system for video bandwidth compression by multiplexing was described in [1]. That scheme was applied to two-level images. Experimental results are given. Seven two-level images were multiplexed and a bandwidth compression by a factor of 2.6 was achieved.
01 Jan 1971
TL;DR: The implementation of a data compression system for the real time operational transmission of advanced technology satellite (ATS) pictures between the command and data acquisition station located at Wallops Island, Virginia and the National Environmental Satellite Service at Suitland, Maryland over broadband microwave links is described.
Abstract: Description of the implementation of a data compression system for the real-time operational transmission (through microwave links) of ATS satellite pictures between the command and data acquisition station and a central location for computer processing. The system features the use of general-purpose minicomputers for encoding and decoding; this makes it possible to vary the employed data compression technique and to make simultaneous statistical calculations on the data. Data compression and expansion is accomplished in a manner that does not lower data quality.
TL;DR: The system is analyzed as a data compressor that enhances the source entropy by replacing redundancies by adding an extra bit to each word to signal the substitution.
Abstract: A redundancy replacement system is described. Whenever m bits of an n -bit word are identical with corresponding bits in the preceding word, these bits are replaced by m bits from a second source. An extra bit is added to each word to signal the substitution. If words with m redundant bits occur with probability P(m) , one gains an extra channel of average capacity mP(m) -- 1 . The system is analyzed as a data compressor that enhances the source entropy by replacing redundancies. An effective data compression of 2.11 is obtained for typical voice sources.