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COMPRESSION OF BINARY FACSIMILE imageS BY PREprocessing AND COLOR SHRINKING

IEEE TRANSACTIONS ON COMMUNICATIONS 1990年第9期38卷 1592-1598页

作者： ALGAZI, VR KELLY, PL ESTES, RR Graphics Image and Vision Engineering Research Laboratory CIPIC Center for Image Processing Integrated Computing University of California Davis CA USA

Algorithms for preprocessing, global modeling and segmentation, local modeling and representation, and binary encoding of facsimile images are proposed, and their performance is examined. Some binary morphological operations that can be used to improve the quality and increase the compressibility of binary images and the modeling of binary images are discussed. The techniques are incorporated into a set of comprehensive encoding schemes, the PCSE codes. Their effectiveness in compressing the International Telegraphy and Telephony Consultative Committee (CCITT) binary images is demonstrated. The PCSE code using preprocessing and color shrinking prior to encoding is shown to outperform the READ code by from 7 to 42% for the standard CCITT test images with a very small change in image quality.< >

关键词： image coding Facsimile image segmentation Morphological operations Encoding Telegraphy Telephony Code standards Testing image quality

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Progressive color block coding of bilevel scanned documents

Progressive color block coding of bilevel scanned documents

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International Conference on Acoustics, Speech, and Signal processing (ICASSP)

作者： V.R. Algazi R.R. Estes G.E. Ford P.L. Kelly CIPIC-Center for Image Processing and Integrated Computing University of California Davis USA

Some preliminary results are presented on a simple progressive code for scanned 300 dpi documents. The effectiveness of the standard CCITT codes as a function of document resolution is determined. Extensions to the technique of document resolution are examined. For higher-resolution scanning, e.g. 300 dpi, a pyramid of the information source which allows for a tradeoff between the compression achieved and the quality of the representation is proposed. A progressive code that first generates a color block image that may be useful for identification of the document is proposed. Progression in quality corresponds to 100 dpi binary images, 100 dpi gray scale images, 300 dpi binary images, and finally 300 dpi gray-scale images. Each stage in the progressive code is based on the data available at the previous stage. The performance of the progressive code is examined.< >

关键词： Block codes Code standards image coding Gray-scale

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Improved color flow mapping using the wideband maximum likelihood estimator

Improved color flow mapping using the wideband maximum likel...

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IEEE Symposium (IUS) Ultrasonics

作者： K.W. Ferrara V.R. Algazi Department of Electrical Engineering California State University Sacramento CA USA Center for Image Processing and Integrated Computing University of California Davis CA USA Department of Electrical Engineering and Computer Science University of California Davis CA USA

The use of the wideband maximum likelihood estimator (MLE) is shown to improve the color flow mapping of the blood velocity profile. Using a transmitted signal with a significant fractional bandwidth, it is shown that the wideband MLE improves the quality of the color flow estimate and simultaneously allows an increase in the frame rate. It is the improved global accuracy of the estimate, with the use of a new signaling scheme, that allows an increase in the frame rate of the display. The signaling scheme interleaves transmission of pulses in two or three directories. This interleaving, with nonperiodic transmission, reduces the total number of pulses required to achieve a fixed level of local and global accuracy. To study the overall estimator performance, the authors evaluate the expected estimator output and demonstrate that the width of the mainlobe and height of subsidiary peaks are reduced through the use of this estimator and signaling scheme.< >

关键词： Wideband Maximum likelihood estimation Blood Displays Simultaneous localization and mapping Transducers Acoustic propagation Delay estimation image processing Bandwidth

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Three-dimensional image analysis and display by space-scale matching of cross sections

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Journal of the Optical Society of America A: Optics and image Science, and Vision 1989年第6期6卷 890-899页

作者： Algazi, V.R. Reutter, B.W. van Warmerdam, W.L.G. Liu, C.C. Graphics Image and Vision Engineering Research Laboratory Center for Image Processing and Integrated Computing University of California Davis CA 95616 United States

We present a framework and a set of techniques for the analysis and display of three-dimensional experimental data or images. We assume that the data are available in the form of two-dimensional cross sections of the three dimensional data set. We describe our approach, which has for goals to extract significant information from the three-dimensional data set and to display this information as objects that can be manipulated in three-dimensional space. The high-contrast transitions of two-dimensional cross sections are extracted first;they define a set of contours to be matched from cross section to cross section. This matching is performed by space-scale analysis of the orientation of contours on adjacent cross sections. By modeling the contours as B splines, we then make use of three-dimensional B-spline patches to generate significant surfaces that can be displayed, rendered, and rotated with standard computer graphics techniques and specialized processors. © 1989 Optical Society of America.

关键词： Computed tomography Computer simulation image analysis image processing Imaging systems Three dimensional imaging

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Digital representation and storage of high quality color images by anisotropic enhancement and subsampling

Digital representation and storage of high quality color ima...

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International Conference on Acoustics, Speech, and Signal processing (ICASSP)

作者： V.R. Algazi G.E. Ford E. Hildum CIPIC Center for Image Processing and Integrated Computing University of California Davis USA

The application of novel anisotropic filter design techniques based on properties of human vision to the processing of luminance and chrominance components of color images is considered. Applied independently, these anisotropic filters can be used for the sequential digital representation of images by subsampling. By using them with two-dimensional quadrature modulation of chrominance signals, they led to a novel scheme for color composite images in which the skewing of energy due to the anisotropy of the filters improves the juxtaposition of luminance and chrominance in the two-dimensional frequency domain. It is found that the image quality is substantially better than that of NTSC images for either sequential or composite techniques.< >

关键词： image storage Color Anisotropic magnetoresistance image coding Anisotropic filters image quality Humans Frequency domain analysis Digital images TV

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Characterization of spectral transitions with applications to acoustic sub-word segmentation and automatic speech recognition

Characterization of spectral transitions with applications t...

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International Conference on Acoustics, Speech, and Signal processing (ICASSP)

作者： K.L. Brown V.R. Algazi Speech Research Laboratory CIPIC Center For Image Processing and Integrated Computing University of California Davis USA

A mathematical model has been developed for tracking spectral transitions within the spectral envelope of a speech signal. This technique incorporates linguistic knowledge into a mathematical framework to determine time-varying acoustic-phonetic features and describe formant transitions. The proposed model is quite robust and is capable of extracting not only rapid spectral movement, but also smoother spectral transitions that occur in vowel and sonorant sequences. This basic approach has been previously used to extract steady-state acoustic-phonetic features across spectrally homogeneous regions and to perform speaker dependent recognition in which quite successful results were attained in clean as well as noisy speech. It has now been augmented to capture the dynamics of spectral acoustic-phonetic features.< >

关键词： Acoustic applications Karhunen-Loeve transforms Speech processing Automatic speech recognition Signal processing Robustness Steady-state Feature extraction Data mining Mathematical model

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A radius-bucketing approach to fast vector quantization encoding

A radius-bucketing approach to fast vector quantization enco...

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International Conference on Acoustics, Speech, and Signal processing (ICASSP)

作者： A. Madisetti R. Subramonian V.R. Algazi Center for Image Process & Integrated Comput. California Univ. Davis CA USA CIPIC Center for Image Processing and Integrated Computing University of California Davis USA

The authors present a computationally efficient encoding scheme for vector quantization. Efficiency is achieved by combining techniques: homes are bucketed into the subset of codewords in the same region as the input point; the energy of the input point eliminates codewords not in the same energy range; the smallest hyperrectangle parallel to the coordinate axes that bounds the Voronoi region associated with the codeword acts as a discriminant; and approximations to the actual distortion are used to avoid multiplications. Simulations on Gaussian sources with ranges of codebook sizes and block sizes indicate that the encoding time, measured in multiplications, actually falls with increasing codebook size. It is shown that with no increase in signal/noise ratio the algorithm substantially outperforms tree search and binary hyperplane testing search.< >

关键词： Vector quantization Encoding image coding Data structures Time measurement Shape Costs image processing Distortion measurement Size measurement

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Robust LPC analysis and synthesis using the KL transformation of acoustic subwords spectra

Robust LPC analysis and synthesis using the KL transformatio...

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International Conference on Acoustics, Speech, and Signal processing (ICASSP)

作者： V.R. Algazi S. Chung M.J. Ready K.L. Brown Center for Image Process. & Integrated Comput. California Univ. Davis CA USA Speech Research Laboratory CIPIC Center of Image Processing and Integrated Computing University of California Davis USA

The authors propose a novel approach to the modeling and estimation of the speech spectral envelope over acoustic subwords that exhibits robust performance in noise. The technique exploits the underlying signal structure of speech to improve parameter estimates, and it uses the perceptual properties of hearing to decrease the computational requirements in a perceptually meaningful way. The approach provides a considerable speech quality improvement over other methods.< >

关键词： Robustness Linear predictive coding Speech analysis Speech enhancement Parameter estimation Speech processing Speech synthesis Working environment noise Speech coding Acoustic noise

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Remote image processing in a workstation environment

Remote image processing in a workstation environment

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International Conference on Acoustics, Speech, and Signal processing (ICASSP)

作者： G.E. Ford G.L. Fisher V.R. Algazi Center for Image Processing and Integrated Computing Research (CIPIC) University of California슠Davis Davis CA USA

Advances in computer networking have opened opportunities for remote image processing, allowing processing tasks to be distributed among specialized nodes. The integrated programming environment, Davis interactive system (DAISY) provides a control panel interface on a workstation to a library of image processing applications that run on specialized remote hosts. The workstation provides an interface to a remote image display, image previews, and an image display.< >

关键词： image processing Workstations Displays Computer networks Distributed computing Programming environments Interactive systems Control systems Libraries Application software

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