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Programmability with its associated flexibility will be increasingly important in future multi-standard radio systems. We are presenting a fully programmable and flexible DSP platform capable of efficiently performing channel estimation and MRC-based channel equalization for several CDMA based wireless transmission systems in software. Our processor is based on a DSP core with SIMD-computing clusters...
In multi-class problems, within- and between-class scatters should be considered in classification criterion. The common vector approach (CVA) uses the discriminative information obtained from within-class scatter of any class. It has been shown that this classical CVA method gives high recognition rates in multi-class problems. In this study, improvements on the CVA method that consider both within-...
In this paper a new class of filters designed for the removal of impulsive noise in color images is presented. The proposed filter class is based on the nonparametric estimation of the density probability function of pixels in a sliding filtering window. The comparison of the new filtering method with the standard techniques used for impulsive noise removal, indicates good noise removal capabilities...
Most edge detection algorithms include three main stages: smoothing, differentiation, and labeling. In this paper, we evaluate the performance of algorithms in which competitive learning is applied first to enhance edges, followed by an edge detector to locate the edges. In this way, more detailed and relatively more unbroken edges can be found as compared to the results when an edge detector is applied...
Text-to-phoneme mapping is a very important preliminary step in any text-to-speech synthesis system. In this paper, we study the performances of the multilayer perceptron (MLP) neural network for the problem of text-to-phoneme mapping. Specifically, we study the influence of the input letter encoding in the conversion accuracy of such system. We show, that for large network complexities the orthogonal...
In this paper, we propose a novel multi-scale edge detection and vector field design scheme. We show that using multiscale techniques edge detection and segmentation quality on natural images can be improved significantly. Our approach eliminates the need for explicit scale selection and edge tracking. Our method favors edges that exist at a wide range of scales and localize these edges at finer scales...
In this paper an approach for integration between GPS and inertial navigation systems (INS) is described. The continuous-time navigation and error equations for an earth-centered earth-fixed INS system are presented. Using zero order hold sampling, the set of equations is discretized. An extended Kalman filter for closed loop integration between the GPS and INS is derived. The filter propagates and...
A new method for generating and animating a 3-D model of a person's face is proposed. The method involves novel algorithms for 2-D to 3-D construction under perspective projection model, real-time mesh deformation using a lower-resolution control mesh, and texture image creation that involves texture blending in 3-D. The resulting face models can be readily used in 3-D games, mobile messaging, e-learning...
Voice conversion techniques enable the transformation of a source speaker's voice to that of a target speaker's automatically. The performance of any voice conversion algorithm depends on the source-target pair chosen. This study focuses on the problem of source speaker (donor) selection from a set of available speakers that will result in the best quality output for a specific target speaker's voice...
This work deals with the problem of estimating the directions of arrival (DOA) of multiple radar targets present in the same range-azimuth resolution cell of a surveillance radar by joint processing the sum (Σ) and delta (Δ) channel data. The AML-RELAX estimator, previously derived by the authors, is extended to a two-channel system, and compared to the classical monopulse system.
Several pro-active acoustic feedback (Larsen-effect) cancellation schemes have been presented for speech applications with short acoustic feedback paths as encountered in hearing aids, but these schemes fail with the long impulse responses inherent to public address systems. We derive a new prediction error method (PEM) based scheme (referred to as PEM-AFROW) which identifies both the acoustic feedback...
A brief introduction to spatial-domain Super-Resolution methods, i.e. spatial resolution enhancement methods that create one high-resolution image from a series of low-resolution images shifted by a sub-pixel distance, is given. An improvement applicable to some of existing Super-Resolution methods is presented. Principles of digital photography processing techniques are exploited in order to reduce...
This paper describes a multi-relay strategy for wireless networks and examines the influence of imperfect channel information on system performance. A modified relay scheme is proposed to compensate for such imperfections.
The main goal of the work here described is the DSP implementation of innovative algorithms for real-time voice transformation. This work represents part of the procedure (developed in the framework of the RACINE-S European Project) conceived for reconstructing voice and dialogue in audio tracks of old and highly damaged film movies.
In this work, tracking analysis of variable normalized least mean fourth (XE-NLMF) algorithm is carried out in the presence of two sources of nonstationarites: 1) carrier frequency offset between transmitter and receiver and 2) random variations in the environment. A novel approach to this analysis is carried out here using the concept of energy conservation. Close agreement between analytical analysis...
We consider the problem of joint angle and doppler estimation for Space-Time Adaptive Processing (STAP) airborne radar in non-gaussian clutter which is modeled as a complex symmetric alpha stable SαS process. We introduce a sign covariance estimate which has almost robust performance in heavy tailed noise [1]. The subspace estimate is calculated via the propagator method [2] to reduce the computational...
Fast Algorithms for the computation of the two-dimensional Discrete Fourier Transform (DCT) can be described by means of elements of Multilinear Algebra. Multilinear Algebra offers not only a formalism for describing the algorithm, but it enables the derivation by pure algebraic manipulations of an algorithm that is well suited to be implemented in vector-SIMD signal processors with different levels...
We treat the problem of reconstructing a signal from its non-ideal samples where the sampling and reconstruction spaces as well as the class of input signals can be arbitrary subspaces of a Hilbert space. If the signal is known to lie in an appropriately chosen subspace, then we propose a method that achieves the minimal squared-error approximation. In the general case, we show that the minimal-error...
This paper introduces a new measure of confusion between phones, based on isolated word recognition tests. This metric combines the advantages of previous measures, and excludes their disadvantages. It can be used for comparing the performance of two speech recognizers at phone level, providing a useful design tool. The main advantage is that tests are made on any set of recorded words, but measure...
In this paper, the lip feature that has the highest correlation with audio features is investigated. Audio features are selected as Mel Frequency Cepstral Coefficients (MFCC) of the audio signal. Three different lip features are considered for the visual lip information, where these features are 2D DCT coefficients of the intensity based image and the optical flow vectors within the lip region, and...
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