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Conference on advanced signal processing - algorithms, architectures, and implementations vII

作者： Winograd, JM Nawab, SH Boston Univ. (United States)

ISBN: (纸本)0819425842

A new architecture is presented for incremental computation of the two-dimensional inverse discrete cosine transform (2D-IDCT) in the context of progressive image decoding. This architecture offers advantages over existing DCT inversion techniques for systems used in conjunction with progressive image coding schemes or those that must operate in environments with severe and/or time-varying resource constraints (e.g. real-time and low-power systems). The use of a bit-serial distributed arithmetic approach comprised of parallel input-pruned 2D-IDCT processing elements enables low-quality image reconstructions to be quickly and efficiently obtained using only a subset of the DCT coefficient bit stream. Initial approximate reconstructions can be improved in subsequent stages of incremental refinement according to the availability of processing resources or DCT coefficient data. Analysis is presented of image degradation at successive stages, illustrating uniform improvement according to quantitative and perceptual criteria.

关键词： progressive image decoding discrete cosine transform incremental refinement approximate processing

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A DEFECT-TOLERANT SYSTOLIC ARRAY IMPLEMENTATION FOR REAL-TIME IMAGE-processing

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JOURNAL OF vLSI signal processing 1993年第1期5卷 37-47页

作者： HECHT, v RONNER, K PIRSCH, P UNIV HANNOVER INFORMAT TECHNOL LABW-3000 HANNOVER 1GERMANY

An advanced defect tolerant systolic array implementation of the 2D convolution algorithm for real time image processing applications has been full-custom designed and fabricated using standard CMOS technology. The bit-serial systolic array incorporates new architectural concepts and circuit techniques fitting a defect tolerant design approach. Therefore high performance and high yield enhancement is achieved. The defect tolerance techniques are based on software controlled defect localization and reconfiguration with programmable switches by a host-processor or a vLSI-tester. The chips functionality differs to available convolution chips by the maximum kernel size of 256 taps, the ability to convolve one video signal with up to four independent coefficient masks, support of adaptive filtering, on-chip line delays and implemented special processing of frames borders. High performance implementations of signal processing algorithms require large chip die sizes. The presented defect tolerance techniques and architectural concepts make systolic large area implementations of signal processing algorithms feasible.

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Two digital video encoder circuits

Two digital video encoder circuits

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advanced signal processing algorithms, architectures, and implementations III

作者： Eldon, John A. TRW LSI Products Inc. La Jolla CA USA

ISBN: (纸本)081940943X

Central to `multimedia' image processing is the desire to encode computer graphics data into a standard television signal, complete with line, field, and color subcarrier synchronizing information. The numerous incompatibilities between television and computer display standards render this operation far less trivial than it sounds to anyone who hasn't worked with both types of signals. To simplify the task of encoding computer graphics signals into standard NTSC (North America and Japan) or PAL (most of Europe) television format for display, broadcast, or recording, TRW LSI Products Inc. has introduced the two newest members of it multimedia integrated circuit family, the TMC22090 and TMC22190 digital video encoders.

关键词： video signal processing

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Efficient implementation of a projection-based wave front sensor

Efficient implementation of a projection-based wave front se...

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Conference on advanced signal processing algorithms, architectures and implementations XII

作者： Holder, J Cain, S Mantica, P Indiana Univ Purdue Univ ITT Aerosp Commun Div Ft Wayne IN 46805 USA

ISBN: (纸本)0819445584

In this paper, a new wave front sensor design that utilizes the benefits of image projections is described and analyzed. The projection-based wave front sensor is similar to a Shack-Hartman type wave front sensor, but uses a correlation algorithm as opposed to a centroiding algorithm to estimate optical tilt. This allows the projection-based wave front sensor to estimate optical tilt parameters while guiding off of point sources and extended objects at very low signal to noise ratios. The implementation of the projection-based wave front sensor is described in detail showings important signal processing steps on and off of the focal plane array of the sensor. In this paper the design is tested in simulation for speed and accuracy by processing simulated astro-nomical data. These simulations demonstrate the accuracy of the projection-based wave front sensor and its superior performance to that of the traditional Shack-Hartman wave front sensor. Timing analysis is presented which shows how the collection and processing of image projections is computationally efficient and lends itself to a wave front sensor design that can produce adaptive optical control signals at speeds of up to 500 hz.

关键词： Wavefront sensors Charge-coupled devices signal to noise ratio Image sensors Sensors Adaptive optics signal processing Detection and tracking algorithms Image processing Astronomy

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Time sequenced adaptive filtering using a modified P-vector algorithm 6

Time sequenced adaptive filtering using a modified P-vector ...

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Conference on advanced signal processing algorithms, architectures, and implementations vI

作者： Williams, R USAF WRIGHT LABAUTOMAT TARGET RECOGNIT DEV BRANCHWRIGHT PATTERSON AFBOH 45433

ISBN: (纸本)0819422347

An adaptive algorithm and two stage filter structure were developed for adaptive filtering of certain classes of signals that exhibit cyclostationary characteristics. The new modified P-vector algorithm (mPa) eliminates the need for a separate desired signal which is typically required by conventional adaptive algorithms. It is then implemented in a time-sequenced manner to counteract the nonstationary characteristics typically found in certain radar and bioelectromagnetic signals. Initial algorithm testing is performed on evoked responses generated by the visual cortex of the human brain with the objective, ultimately, to transition the results to radar signals. Each sample of the evoked response is modeled as the sum of three uncorrelated signal components, a time-varying mean (M), a noise component (N), and a random jitter component (Q). A two stage single channel time-sequenced adaptive filter structure was developed which improves convergence characteristics by de coupling the time-varying mean component from the `Q' and noise components in the first stage. The EEG statistics must be known a priori and are adaptively estimated from the pre stimulus data. The performance of the two stage mPa time-sequenced adaptive filter approaches the performance for the ideal case of an adaptive filter having a noiseless desired response.

关键词： time sequenced adaptive filter EEG biomedical signal processing radar signal processing

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Rijndael FPGA implementations utilising look-up tables

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Journal of vLSI signal processing Systems for signal, Image, and video Technology 2003年第3期34卷 261-275页

作者： McLoone, Máire McCanny, John v. DSiPtrade Laboratories Sch. of Elec. and Electronic Eng. Queen's University of Belfast Belfast United Kingdom

This paper presents single-chip FPGA Rijndael algorithm implementations of the advanced Encryption Standard (AES) algorithm, Rijndael. In particular, the designs utilise look-up tables to implement the entire Rijndael Round function. A comparison is provided between these designs and similar existing implementations. Hardware implementations of encryption algorithms prove much faster than equivalent software implementations and since there is a need to perform encryption on data in real time, speed is very important. In particular, Field Programmable Gate Arrays (FPGAs) are well suited to encryption implementations due to their flexibility and an architecture, which can be exploited to accommodate typical encryption transformations. In this paper, a Look-Up Table (LUT) methodology is introduced where complex and slow operations are replaced by simple LUTs. A LUT-based fully pipelined Rijndael implementation is described which has a pre-placement performance of 12 Gbits/sec, which is a factor 1.2 times faster than an alternative design in which look-up tables are utilised to implement only one of the Round function transformations, and 6 times faster than other previous single-chip implementations. Iterative Rijndael implementations based on the Look-Up-Table design approach are also discussed and prove faster than typical iterative implementations.

关键词： algorithms

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An algorithm for weighted least squares positive time-frequency distributions

An algorithm for weighted least squares positive time-freque...

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Conference on advanced signal processing - algorithms, architectures, and implementations vII

作者： Pitton, JW MathSoft Seattle WA 98109 1700 Westlake Ave N United States

ISBN: (纸本)0819425842

An algorithm for computing positive time-frequency distributions (TFDs) for nonstationary signals is presented. This work extends the earlier work of the author and his colleagues in computing positive TFDs [11, 15]. A general approach to the problem of computing these signal-dependent distributions is derived. The method is based on an evolutionary spectrum formulation of positive TFDs. Following earlier work [15], a relationship is derived between positive TFDs and the ambiguity function of the observed signal. In particular, it is shown that the TFD is approximately equal to the two-dimensional Fourier transform of the ambiguity function. A method for computing the positive TFD is then presented based on minimizing the squared error in this approximation subject to the TFD being positive and satisfying the time and frequency marginals. The squared error may be weighted non-uniformly, resulting in a constrained weighted least-squares optimization problem. A solution to this optimization problem based on an alternating projections framework is presented, and an example is provided. The resulting TFD provides excellent time-frequency resolution while maintaining positivity and satisfying the marginals.

关键词： signal processing time-frequency analysis time-varying signals optimization alternating projections

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Design and evaluation of automated checks for signal processing applications 6

Design and evaluation of automated checks for signal process...

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Conference on advanced signal processing algorithms, architectures, and implementations vI

作者： Nair, vSS Kim, HC Krishnamurthy, N Abraham, JA SO METHODIST UNIV DEPT COMP SCI & ENGNDALLASTX 75275

ISBN: (纸本)0819422347

Most of the signal processing application programs involve computationally intensive iterative steps. In such programs, various failures in the underlying hardware manifest as control-flow errors that affect the reliability of the computed results. various techniques have been proposed in the past to detect and recover from such control-flow errors. Unfortunately, all these techniques need either additional hardware or modification of the hardware and are not portable across various platforms. To circumvent these limitations, recently we have developed a high-level control-flow checking approach using assertions (CCA). In CCA, branch-free intervals in a given high-level language program are identified and the entry and exit points of the intervals are fortified through pre-inserted assertions. In this paper we describe an implementation of CCA through a pre-processor that will automatically insert the necessary assertions into a high-level language program. Based on the implementation we study the fault detection capabilities of CCA with the help of fault injection experiments using FERRARI.

关键词： Simulation of CCA and DLA aggregates Switches signal processing Reliability Computing systems Computer engineering Data modeling Error analysis Error control coding Computer science

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NRL FLEX radar signal-processing architecture: an update

NRL FLEX radar signal-processing architecture: an update

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advanced signal processing algorithms, architectures, and implementations III

作者： Alter, James J. Evins, James B. Popick, Glen L. Scott, Russell A. Letellier, J.P. Naval Research Lab. Washington DC USA

ISBN: (纸本)081940943X

The NRL FLEX processor architecture is designed for real-time radar signal processing and was described at last year's conference in the context of its original application, the Point Defense Demonstration Radar project at NRL. This paper describes the current status of the processor and the application of the same architecture to a new problem which requires a different board configuration to satisfy a different set of latency and data flow requirements.

关键词： Radar systems

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A higher order method for concentrating the STFT

A higher order method for concentrating the STFT

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advanced signal processing algorithms, architectures, and implementations Xv

作者： Nelson, D.J. Smith, D.C. R61 U.S. Dept. of Defense Ft. Meade MD 20755 United States

We present a method for computing the theoretically exact estimate of the instantaneous frequency of a signal from local values of its short time Fourier transform under the assumption that the complex logarithm of the signal is a polynomial in time. We apply the method to the problem of estimating and separating non-stationary components of a multi-component signal. signal estimation and separation is based on a linear TF model in which the value of the signal at each time is distributed in frequency. This is a significant departure from the conventional nonlinear model in which signal energy is distributed in time and frequency. We further demonstrate by a simple example that IF estimated by the higher order method is significantly better than previously used first order methods.

关键词： signal processing

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