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A novel adaptive VQ based subband coding scheme for very low bit rate coding of video sequences is presented. Overlapped block motion estimation/compensation is employed to exploit interframe redundancy. A 2D wavelet transform (WT) is applied to the resulting displaced frame difference (DFD) signal. The WT coefficients are encoded using an adaptive vector quantization scheme in combination with a...
Current research into automatic language identification systems sees the problem as being related to speaker independent speech recognition and speaker identification. In particular, speaker indentification methods appear to outperform all other other methods and the incorporation of prosodie information has contributed only marginally to their success. This is a counterintuitive result suggesting...
In previous works [5], [6], we studied some speech enhancement algorithms based on the iterative Wiener filtering method due to Lim-Oppenheim [2], where the AR spectral estimation of the speech is carried out using a second-order analysis. But in our algorithms we consider an AR estimation by means of cumulant analysis. This work extends some preceding papers due to the authors: a cumulant-based Wiener...
Line scratches are a common problem in archived motion pictures. They are caused by the abrasion of the film material as it passes through the projection mechanism. This paper presents a technique for detecting and removing these line artefacts. The method employs a model of the line profile for detection and the 2D Autoregressive model (2D AR) of the image for interpolation.
In this paper we present a text-independent offline writer recognition system based on multilayer perceptrons (MLPs). The system can be used for both identification and verification purposes. It was tested on a population of 20 writers with non-correlated training and test specimens. The mean error for identification was 3.5% while error rates as low as 0.5% were achieved on specimens with more than...
In this paper a new parameter estimation based criterion for two-point resolution is proposed. Unlike the classical resolution criteria, the new criterion takes account of noise and systematic errors. A resolution limit in terms of the observations is derived. This limit depends on the point spread function used and the degree of coherence supposed. For statistical observations the probability of...
A simple discrete version of B-splines is proposed. The proposed discrete version has different values from B-splines at the discrete points, but it is proven that the proposed discrete version tends to B-splines when the sampling interval goes to zero. They can be evaluated more quickly than the former discrete B-splines, only by RRS digital filters.
In this paper, described tunable digital bandpass filters whereby the centre frequency and bandwidth can be independently related to the multiplier coefficients, which permit simple frequency response adjustment by varying the coefficients values. The bandpass filters proposed here have a cascade form and are composed of several second-order recursive bandpass sections with identical characteristics...
The digital signal processing system design consists in four synthesis phases which concern the processing, the control, the memory and the communication units. Today, many tools enables us to produce the processing unit. However, in many applications, the hardware solution may be challenged by the number and complexity of memories. This paper proposes a design methodology of the memory units for...
In a recent paper Mulgrew [1] proposed a nonlinear filtering structure which utilises a set of orthonormal expansions to model nonlinear dynamical systems. Provisional results were presented for a simple 1-dimensional system. In this paper we extend the analysis of this structure to multi-dimensional filtering, and examine the application of the orthonormal structure for nonlinear system identification...
Three new Block Code Diversity combing schemes for digital transmission over a Rayleigh fading channel have been proposed. It has been shown that improved performance in term of probability of error versus signal to noise ratio has been obtained using soft-decision Viterbi decoding together with diversity techniques. Simulation results have been included to verify the performance of the proposed schemes.
This paper presents the design and implementation of the PC-based multitasking system HERMES, which supports the development of concurrent Digital Signal Processing (DSP) applications using object-oriented programming techniques under the MS-DOS operating system. The signal abstractions by Objects of the HERMES system and its architecture are described along with the software framework that enables...
This paper describes a new algorithm for performing erosion and dilation which is suitable for flat line-segment structuring functions, and which has a computational complexity that is independent of the structuring function size. Unlike other proposed algorithms, the computation time required by this method is directly proportional to the number of extrema within the signal being processed. This...
In this paper we present a novel parallel sorting algorithm, highly suited for VLSI implementation, which works through a cascade of elementary sorting units and leads to a scalable architecture. The paper describes the applications of such device to the asynchronous data acquisition for a gamma ray telescope.
The real-time Image and signal processing applications, such as — vision, image synthesis, HDTV, signal processing, neural networks, require both computing and input/output power. The GFLOPS project is dedicated to the study of all the aspects concerning the design of such computers. Its aim is to develop a parallel architecture as well as its software environment to implement those applications efficiently...
In this work a tracking algorithm which extracts the vascular network structure from fundus Scanning Laser Ophthalmoscope (SLO) images is presented. The tracking algorithm is based on a priori knowledge of the vessel structure. It exploits the continuity of radius, position, direction and brightness of a blood vessel and is based on a recursive strategy. First, a main vessel is tracked and its branch...
We describe a method for textural feature extraction of MRI volumes of the brain and, based upon those features, a method for classification and assessment of the anatomical malformations of the brain, due to Alzheimer's Disease (AD). In our research, we make the hypothesis that there is enough detectable textural evidence from a 3D analysis of MR images of the brain to detect and identify the earliest...
The wavelet transform provides a time-scale analysis that permits flexible pattern recognition, component identification, and detection of transients for time-varying neural signals such as the EEG, event-related potentials, neuromagnetic signals, and other neural signals and images. Many future applications to neural signals will benefit from choosing a mother wavelet that mimics neural waveform...
It is one of the primary responsibilities of any department of diagnostic radiology to minimize the amount of unnecessary radiation administered to patients during diagnostic procedure. In this paper, we present three effective ways of quantifying the information content of computed radiography (CR) images for radiation dose optimization through shape and wavelet analyses. The experimental results...
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