A skew estimation algorithm for printed and handwritten documents, based on the document’s horizontal projection profile and its Wigner–Ville distribution, is presented. The proposed algorithm is able to correct skew angles that range between 289 and þ898 detecting the right oriented position of the page by the alternations of the horizontal projection profile. It is able of processing successf...

Time-frequency distributions (TFDs) are powerful tools to represent the energy content of time-varying signal in both time and frequency domains simultaneously but they suffer from interference due to cross-terms. Various methods have been described to remove these cross-terms and they are typically signal-dependent. Thus, there is no single TFD with a fixed window or kernel that can produce ac...

It has been shown that detailed information from non-stationary signals such as speech are better represented by an acoustic image, a two dimensional feature representation [10]. Several time frequency representations such as the spectrogram, Wigner-ville and choi-williams distribution have been proposed [6] while the acoustic images based on the two dimensional root cepstrum analysis (TDRC) is...

In case of a strong frequency modulated interference in a spread spectrum communication system, the interference can be effectively suppressed by applying a time-varying notch filter with its zero(s) placed at an instantaneous frequency (IF) estimate of the interference. In this paper, we present the use of a timevarying autoregressive model based IF estimator in such a scenario. We model the r...

This article describes the CALST project, in which the primary aim is to develop Ville-N, a CAPT system for learners of Norwegian as a second language. Since there is no accepted pronunciation standard in Norwegian, the system uses four dialects (represented by one male and one female speaker each). Ville-N makes use of L1-L2map, a tool for multilingual contrastive analysis, to generate a list ...

Département de Biochimie, Université de Montréal, C.P. 6128, Succursale centre-ville, 9 Montréal, Québec, H3C 3J7, Canada. 10 Department of Bioengineering, McGill University, Montreal, Quebec, H3A0C3, Canada. 11 Ernest Rutherford Physics Building, 3600 rue University, McGill University, Montreal, Québec, 12 H3A2T8 13 Department of Biomedical Engineering and Center for Biological Systems Enginee...

Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time-frequency analysis techniques, such as the Wigner-Ville distribution, ChoiWilliams distribution, spectrogram, and scalogram, for the purpose of analyzing low probability of intercept radar signals (e.g. triangular modulated frequency modulated continuous wave and frequency shift keying)....

An optimised time-frequency signal analysis software tool is presented here as a MATLAB toolbox. This toolbox is implemented using existing and novel methods for a specific class of Time-Frequency Distributions (TFDs) called quadratic TFDs. This is first applied to a TFD called the Wigner-Ville Distribution (WVD), as all other quadratic TFDs can be represented as a smoothed (in both time and fr...

This paper presents a new approach based on spatial time–frequency averaging for separating signals received by a uniform linear antenna array. In this approach, spatial averaging of the time–frequency distributions (TFDs) of the sensor data is performed at multiple time–frequency points. This averaging restores the diagonal structure of the source TFD matrix necessary for source separation. Wi...