Highly efficient coding schemes for contour line drawings

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A multiresolution approach for the coding of edges of still images using adaptive arithmetic coding

International audienceAn edge coding scheme based on chain code representation in a multiresolution image coding context is presented. Our method enhances the coding schemes that describe the source structure with Markov models, by using also an a priori knowledge from the previous decoded resolution images. Experiments using adaptive arithmetic coding have shown up to a 5% improvement for the bitrate compared to a Markovian scheme

Data compression for satellite images

An efficient data compression system is presented for satellite pictures and two grey level pictures derived from satellite pictures. The compression techniques take advantages of the correlation between adjacent picture elements. Several source coding methods are investigated. Double delta coding is presented and shown to be the most efficient. Both predictive differential quantizing technique and double delta coding can be significantly improved by applying a background skipping technique. An extension code is constructed. This code requires very little storage space and operates efficiently. Simulation results are presented for various coding schemes and source codes

An assessment of technology alternatives for telecommunications and information management for the space exploration initiative

On the 20th anniversary of the Apollo 11 lunar landing, President Bush set forth ambitious goals for expanding human presence in the solar system. The Space Exploration Initiative (SEI) addresses these goals beginning with Space Station Freedom, followed by a permanent return to the Moon, and a manned mission to Mars. A well designed, adaptive Telecommunications, Navigation, and Information Management (TNIM) infrastructure is vital to the success of these missions. Utilizing initial projections of user requirements, a team under the direction of NASA's Office of Space Operations developed overall architectures and point designs to implement the TNIM functions for the Lunar and Mars mission scenarios. Based on these designs, an assessment of technology alternatives for the telecommunications and information management functions was performed. This technology assessment identifies technology developments necessary to meet the telecommunications and information management system requirements for SEI. Technology requirements, technology needs and alternatives, the present level of technology readiness in each area, and a schedule for development are presented

An investigation into artificial intelligence based generative computer process planning

The process planning function can be further optimized with the introduction of an intelligent software package such as an Artificial Intelligence based Generative Computer Process Planning System. An AI based CAPP system, also categorized as an expert system, provides the vital link between design and manufacture, a bridge of knowledge in the information chain of manufacturing engineering. With the increasing role of computers in the process planning function, planning has become easier, faster, and more efficient. This thesis provides an explanation of the process planning function and how artificial intelligence will improve it. Topics in AI techniques and procedures, knowledge engineering, Computer Aided Design, and Group Technology (GT) are discussed. Utilizing the topics presented, a complete interactive software system is presented to illustrate the flexibility of an AI based CAPP system

Data compression techniques applied to high resolution high frame rate video technology

An investigation is presented of video data compression applied to microgravity space experiments using High Resolution High Frame Rate Video Technology (HHVT). An extensive survey of methods of video data compression, described in the open literature, was conducted. The survey examines compression methods employing digital computing. The results of the survey are presented. They include a description of each method and assessment of image degradation and video data parameters. An assessment is made of present and near term future technology for implementation of video data compression in high speed imaging system. Results of the assessment are discussed and summarized. The results of a study of a baseline HHVT video system, and approaches for implementation of video data compression, are presented. Case studies of three microgravity experiments are presented and specific compression techniques and implementations are recommended

Design of a digital compression technique for shuttle television

The determination of the performance and hardware complexity of data compression algorithms applicable to color television signals, were studied to assess the feasibility of digital compression techniques for shuttle communications applications. For return link communications, it is shown that a nonadaptive two dimensional DPCM technique compresses the bandwidth of field-sequential color TV to about 13 MBPS and requires less than 60 watts of secondary power. For forward link communications, a facsimile coding technique is recommended which provides high resolution slow scan television on a 144 KBPS channel. The onboard decoder requires about 19 watts of secondary power