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A multi-view face detection and pose estimation system has been developed employing the edge-based feature representations. Using the posed face images at four angles: 0°, 30°, 60°, and 90° as templates, the performance of pose estimation of about 80% has been achieved for test images in the entire angle range of 0° – 90°. In order to further enhance the performance, the concept of focus-of-attention...
An object tracking scheme based on mutual information is proposed in this paper. First, coarse tracking is performed by using mutual information maximization. Subsequently the tracking output is refined by the use of a deformable contour scheme based on image gradient and mutual information which allows the tracking system to capture the variation of the tracked object contour. The scheme was tested...
Departing from the opportunistic schemes in Multiuser Broadcast MIMO schedulers, practical transmission techniques to get closer to the channel capacity are proposed for the outdoor urban scenario. By considering the Spatial Power Density function of the arriving signal, the paper develops different setups based on the quantity of available Channel State Information at the Transmitter side (CSIT)...
The maximum likelihood (ML) approach for estimating direction of arrival (DOA) plays an important role in array processing. Its consistency and efficiency have been well established in the literature. A common assumption is that the number of signals is known. In many applications, this information is not available and needs to be estimated. However, the estimated number of signals does not always...
This paper estimates the inverse filter of a signal transmission channel of a room driven by a speech signal. Speech signals are often modeled as piecewise stationary autoregressive (AR) processes. The most fundamental issue is how to estimate a channel's inverse filter separately from the inverse filter of the speech generating AR system, or the prediction error filter (PEF). We first point out that...
In modern DSL systems, crosstalk is a major source of performance degradation. Crosstalk cancellation techniques have been proposed to mitigate the effect of crosstalk. However, the complexity of these crosstalk cancellation techniques grows with the square of the number of lines. Therefore one has to be selective in cancelling crosstalk to reduce complexity. Secondly, crosstalk cancellation requires...
In this article we prove that a computable tree-like interconnection of parallel/series Wave Digital adaptors with memory (which are characterized by reflection filters instead of reflection coefficients) is equivalent to a standard (instantaneous) multi-port adaptor whose ports are connected tomutators (2-port adaptors with memory). We prove this by providing a methodology for extracting the memory...
An efficient approach to mitigate the howling effect in hearing aids is via the use of Acoustic Feedback Cancellation (AFC). In this paper, the use of a Forward Linear Predictor (FLP) is investigated to improve the performance of an AFC system in multi-band hearing aids. The FLP is used to predict the speech input signal before eliminating it from the error signal of the AFC system. Computer simulations...
This paper proposes a new variable forgetting factor QR-based recursive least M-estimate (VFF-QRRLM) adaptive filtering algorithm for impulsive noise environment. The new algorithm is a QR-based implementation of the RLM algorithm, which offers better numerical stability and a similar robustness to impulsive noise. A new VFF control scheme based on the approximated derivatives of the filter coefficients...
We investigate the association between constellation shaping and bit-interleaved coded modulation with iterative decoding (BICM-ID). To this end, we consider a technique which consists of inserting shaping block codes between mapping and channel coding functions in order to achieve constellation shaping. By assuming the example of a 2-bit/s/Hz 16-QAM BICM-ID, it is demonstrated using computer simulations...
This work concerns quality improvement of auto-fluorescence retinal images by averaging of non-rigidly registered images. The necessity of using the elastic spatial transformation model is documented as well as the need for similarity criterion capable of dealing with the non-homogenous and variable illumination of retinal images. The presented multilevel registration algorithm provides parameters...
In this paper, the average of the steady state excess mean square error (ASEMSE) of the least mean kurtosis (LMK) adaptive algorithm is theoretically derived. It is done by applying the energy conservation behavior of adaptive filters and it is based on the n-th order correlations and cumulants theory. By doing so, the behavior of the recently proposed LMK can be predicted, so that it can be widely...
We propose a new method for roughness analysis of soil surfaces based on a multiscale approach. Tilled surfaces are decomposed into a large scale oriented structure due to the tillage practice and a non-orderly spatial distribution of clods. The multiresolution approximations of the soil surface allow to characterize these two components. The approximation at the level 4 enhances the large scale oriented...
A new approach to the frequency reassignment for sinusoidal energy localization in the time-frequency plane is presented. While the classical reassignment method operates statically on each point in the plane, a more global approach focuses on the dynamics of the frequency reassignment operator along the frequency grid. It is shown that the first mixed moment of the frequency reassignment operator...
As a time-frequency tool, the Continuous Wavelet Transform (CWT) was applied in radar imaging to reveal that the reflectors' response varies as a function of frequency f and aspect angle q (orientation of the wave vector). To do so, we constructed a hyperimage expressed as the squared modulus of the wavelet coefficients, allowing to access to the energy distribution of each reflector, in the f - θ...
Modern wireless systems employ highly integrated hardware. Especially for the processing at radio frequencies, this high integration causes many undesired effects of signal distortion and degradation that must be simulated comprehensively before finalizing the system design. However, often the model accuracy is not sufficient to obtain sound results of the simulations; and in the case of sufficiently...
This paper presents the theory and lattice structures of a large class of oversampled linear phase paraunitary filter banks. We deal with FIR filter banks with real-valued coefficients in which all analysis filters have the same arbitrary filter length and share the same symmetry center. Necessary existence conditions on symmetry polarity of the filter banks are firstly derived. Lattice structures...
We introduce a new technique for the classification of motor imagery electroencephalogram (EEG) recordings in a Brain Computer Interface (BCI) task. The technique is based on an adaptive time-frequency analysis of EEG signals computed using Local Discriminant Bases (LDB) derived from Local Cosine Packets (LCP). Unlike prior work on adaptive time-frequency analysis of EEG signals, this paper uses arbitrary...
We propose a multi-step procedure for constructing a confidence interval for the number of signals present. The proposed procedure uses the ratios of a sample eigenvalue and the sum of different sample eigenvalues sequentially to determine the upper and lower limits for the confidence interval. A preference zone in the parameter space of the population eigenvalues is defined to separate the signals...
The widely used Matching Pursuit algorithm processes the input signal as a whole, and as such does not build relationships between atoms that are selected at every iteration. For audio signals, variants of this algorithm have been introduced that catch structured sets of atoms (“molecules”) sharing common properties: harmonic relationship, time-frequency proximity. However, they are limited by the...
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