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Codes with Monotonic Codeword Lengths.
Peer reviewed Peer reviewed
Abrahams, Julia – Information Processing & Management, 1994
Discusses the minimum average codeword length coding under the constraint that the codewords are monotonically nondecreasing in length. Bounds on the average length of an optimal monotonic code are derived, and sufficient conditions are given such that algorithms for optimal alphabetic codes can be used to find the optimal monotonic code. (six…
Descriptors: Algorithms, Coding, Illustrations, Information Theory
Tomographic Image Compression Using Multidimensional Transforms.
Peer reviewed Peer reviewed
Villasenor, John D. – Information Processing & Management, 1994
Describes a method for compressing tomographic images obtained using Positron Emission Tomography (PET) and Magnetic Resonance (MR) by applying transform compression using all available dimensions. This takes maximum advantage of redundancy of the data, allowing significant increases in compression efficiency and performance. (13 references) (KRN)
Descriptors: Coding, Comparative Analysis, Illustrations, Information Storage
Subband Image Coding Using Entropy-Constrained Residual Vector Quantization.
Peer reviewed Peer reviewed
Kossentini, Faouzi; And Others – Information Processing & Management, 1994
Discusses a flexible, high performance subband coding system. Residual vector quantization is discussed as a basis for coding subbands, and subband decomposition and bit allocation issues are covered. Experimental results showing the quality achievable at low bit rates are presented. (13 references) (KRN)
Descriptors: Coding, Evaluation, Experiments, Illustrations
Progressive Image Coding by Hierarchical Linear Approximation.
Peer reviewed Peer reviewed
Wu, Xiaolin; Fang, Yonggang – Information Processing & Management, 1994
Proposes a scheme of hierarchical piecewise linear approximation as an adaptive image pyramid. A progressive image coder comes naturally from the proposed image pyramid. The new pyramid is semantically more powerful than regular tessellation but syntactically simpler than free segmentation. This compromise between adaptability and complexity…
Descriptors: Coding, Comparative Analysis, Evaluation, Illustrations
Online Adaptive Vector Quantization with Variable Size Codebook Entries.
Peer reviewed Peer reviewed
Constantinescu, Cornel; Storer, James A. – Information Processing & Management, 1994
Presents a new image compression algorithm that employs some of the most successful approaches to adaptive lossless compression to perform adaptive online (single pass) vector quantization with variable size codebook entries. Results of tests of the algorithm's effectiveness on standard test images are given. (12 references) (KRN)
Descriptors: Algorithms, Coding, Data Processing, Evaluation
Image-Data Compression Using Edge-Optimizing Algorithm for WFA Inference.
Peer reviewed Peer reviewed
Culik, Karel II; Kari, Jarkko – Information Processing & Management, 1994
Presents an inference algorithm that produces a weighted finite automata (WFA), in particular, the grayness functions of graytone images. Image-data compression results based on the new inference algorithm produces a WFA with a relatively small number of edges. Image-data compression results alone and in combination with wavelets are discussed.…
Descriptors: Algorithms, Coding, Comparative Analysis, Data Processing
Comprehension of Graphics in Text.
Peer reviewed Peer reviewed
De Corte, Erik, Ed. – Learning and Instruction, 1993
The eight articles and two commentaries of this theme issue indicate the main lines of thinking represented at a symposium on the comprehension of graphics in text. The common assumption is that graphics per se do not have a direct effect on learning results but are effective only when processed adequately. (SLD)
Descriptors: Charts, Coding, Cognitive Processes, Diagrams