2002 14th International Conference on Digital Signal Processing Proceedings. DSP 2002 (Cat. No.02TH8628)
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Improving the speed and performance of adaptive equalizers via transform based adaptive filtering
Tập 2 - Trang 1301-1304 vol.2
Adaptive equalizers are widely used in many communication systems where the channel frequency response characteristics are either time varying or unknown such as the case in wireless and dial up telecommunication networks where the communication channel constantly change due to the different packet routes and switching that takes place, as well as due to the changes in the RF propagation. This wor......
#Adaptive equalizers #Adaptive filters #Discrete Fourier transforms #Discrete wavelet transforms #Fourier transforms #Discrete cosine transforms #Eigenvalues and eigenfunctions #Frequency response #Time varying systems #Communication channels
Recursive non parametric spectral estimation from irregularly sampled observations
Tập 2 - Trang 799-802 vol.2
In this paper, the nonparametric spectral analysis of a randomly sampled signal is discussed. In particular, a class of estimators is introduced: the IRINCORREL class. This class is composed of recursive algorithms which both take into account the sampling irregularity and the correlation of the signal values. The study of the mean square estimation error shows that there is a trade off between bi......
#Recursive estimation #Sampling methods #Spectral analysis #Signal processing algorithms #Frequency #Random variables #Large Hadron Collider #Estimation error #Convergence #Signal processing
Stochastic search algorithms for optimal content-based sampling of video sequences
Tập 2 - Trang 551-554 vol.2
A video content representation framework is proposed in this paper, for extracting limited, but meaningful, information of video data, directly from the MPEG compressed domain. In particular, extraction of several representative shots is performed for each video sequence in a content based rate sampling framework. An approach, based on minimization of a cross-correlation criterion of the video fra......
#Stochastic processes #Sampling methods #Video sequences #Video on demand #Multimedia systems #Data mining #Videoconference #Communications technology #Information retrieval #Computer aided instruction
A novel channel coding scheme based on continuous-time chaotic dynamics
Tập 2 - Trang 1321-1324 vol.2
One of the most outstanding properties of chaotic dynamical systems is their extreme sensitivity to small perturbations. Far from being a disadvantage, this feature can be exploited to devise a simple technique that allows to control the symbolic dynamics of a chaotic system by applying small perturbations to the system trajectory. In this paper, we show how this procedure can be employed to diffe......
#Channel coding #Chaos #Chaotic communication #Control systems #Redundancy #Error correction codes #Decoding #Computer simulation #State-space methods
Wavelet-based fixed and embedded L-infinite-constrained coding
Tập 2 - Trang 509-512 vol.2
A new wavelet-based L-infinite-constrained fixed and embedded coding technique is proposed in this paper. For any desired distortion bound, the embedded bit stream can be truncated at a corresponding bit-rate, for which the required upper bound on the individual elements of the reconstruction error signal is guaranteed. The original signal can also be coded up to a fixed a priori user-defined dist......
#Image reconstruction #Wavelet domain #Wavelet transforms #Distortion #Upper bound #Image coding #Error correction codes #Wavelet coefficients #Partitioning algorithms #Information processing
Efficient real-time noise estimation without explicit speech, non-speech detection: an assessment on the AURORA corpus
Tập 2 - Trang 985-988 vol.2
This paper addresses the problem of noise estimation for speech enhancement and automatic speech recognition. In the context of mobile telephony, there is a requirement for low resource algorithms which must run at real-time. This paper describes the implementation of a previously published approach, termed quantile-based noise estimation, integrated within a conventional spectral subtraction fram......
#Speech enhancement #Automatic speech recognition #Telephony #Speech recognition #Proposals #Noise robustness #Additive noise #Background noise #Network servers #Telecommunication traffic
Audio-visual speech recognition by speechreading
Tập 2 - Trang 1069-1072 vol.2
Speechreading increases intelligibility in human speech perception. This suggests that conventional acoustic-based speech processing can benefit from the addition of visual information. This paper exploits speechreading for joint audio-visual speech recognition. We first present a color-based feature extraction algorithm that is able to extract salient visual speech features reliably from a fronta......
#Speech recognition #Hidden Markov models #Humans #Speech processing #Feature extraction #Data mining #Video sequences #Maintenance #Streaming media #Audio-visual systems
A medical acoustic signal analysis method based on Zipf law
Tập 2 - Trang 615-618 vol.2
We present in this paper a medical signal analysis method that we have developed in order to study, in an atraumatic and non-invasive way, the inferior oesophageal sphincter behaviour. This one plays an important part in the gastro-oesophageal reflux phenomenon. The proposed method is more efficient and is better suited to our problem than traditional signal processing methods that did not give go......
#Biomedical acoustics #Signal analysis #Signal processing #Pathology #Discrete wavelet transforms #Medical signal detection #Signal detection #Time frequency analysis #Acoustic measurements #Diseases
Implementation of multi-channel AAC encoder for high quality audio broadcasting
Tập 2 - Trang 835-838 vol.2
In this paper, we describe the implementation of the multi-channel AAC encoder system for digital audio broadcasting. The encoder system is based on MPEG-2/4 advanced audio coding (AAC) and is capable of real-time encoding up to 5.1 channel audio. To give a flexible functionality, it consists of multiple DSPs, IEC61937 and TCP/IP interface and 6 channel audio input facilities. The reference AAC de......
#Digital signal processing #Clocks #Digital audio broadcasting #Frequency synchronization #Streaming media #Control systems #Psychoacoustic models #Computer architecture #Sampling methods #Signal sampling
Visual speech recognition using support vector machines
Tập 2 - Trang 1093-1096 vol.2
In this paper we propose a visual speech recognition network based on support vector machines. Each word of the dictionary is described as a temporal sequence of visemes. Each viseme is described by a support vector machine, and the temporal character of speech is modeled by integrating the support vector machines as nodes into a Viterbi decoding lattice. Experiments conducted on a small visual sp......
#Speech recognition #Support vector machines #Mouth #Hidden Markov models #Dictionaries #Viterbi algorithm #Lattices #Active shape model #Real time systems #Informatics