The Experts below are selected from a list of 29301 Experts worldwide ranked by ideXlab platform
Gael Richard - One of the best experts on this subject based on the ideXlab platform.
-
informed audio source separation a comparative study
European Signal Processing Conference, 2012Co-Authors: Antoine Liutkus, Roland Badeau, Laurent Girin, Laurent Daudet, Stanislaw Gorlow, Sylvain Marchand, Nicolas Sturmel, Shuhua Zhang, Gael RichardAbstract:The goal of source separation algorithms is to recover the constituent sources, or audio objects, from their mixture. However, blind algorithms still do not yield estimates of sufficient quality for many practical uses. Informed Source Separation (ISS) is a solution to make separation robust when the audio objects are known during a so-called Encoding Stage. During that Stage, a small amount of side information is computed and transmitted with the mixture. At a decoding Stage, when the sources are no longer available, the mixture is processed using the side information to recover the audio objects, thus greatly improving the quality of the estimates at a cost of additional bitrate which depends on the size of the side information. In this study, we compare six methods from the state of the art in terms of quality versus bitrate, and show that a good separation performance can be attained at competitive bitrates.
-
informed source separation through spectrogram coding and data embedding
Signal Processing, 2012Co-Authors: Antoine Liutkus, Roland Badeau, Laurent Girin, Jonathan Pinel, Gael RichardAbstract:We address the issue of underdetermined source separation in a particular informed configuration where both the sources and the mixtures are known during a so-called Encoding Stage. This knowledge enables the computation of a side-information which is small enough to be inaudibly embedded into the mixtures. At the decoding Stage, the sources are no longer assumed to be known, only the mixtures and the extracted side-information are processed for source separation. The proposed system models the sources as independent and locally stationary Gaussian processes (GP) and the mixing process as a linear filtering. This model allows reliable estimation of the sources through generalized Wiener filtering, provided their spectrograms are known. As these spectrograms are too large to be embedded in the mixtures, we show how they can be efficiently approximated using either Nonnegative Tensor Factorization (NTF) or image compression. A high-capacity embedding method is used by the system to inaudibly embed the separation side-information into the mixtures. This method is an application of the Quantization Index Modulation technique applied to the time-frequency coefficients of the mixtures and permits to reach embedding rates of about 250kbps. Finally, a study of the performance of the full system is presented.
Antoine Liutkus - One of the best experts on this subject based on the ideXlab platform.
-
informed audio source separation a comparative study
European Signal Processing Conference, 2012Co-Authors: Antoine Liutkus, Roland Badeau, Laurent Girin, Laurent Daudet, Stanislaw Gorlow, Sylvain Marchand, Nicolas Sturmel, Shuhua Zhang, Gael RichardAbstract:The goal of source separation algorithms is to recover the constituent sources, or audio objects, from their mixture. However, blind algorithms still do not yield estimates of sufficient quality for many practical uses. Informed Source Separation (ISS) is a solution to make separation robust when the audio objects are known during a so-called Encoding Stage. During that Stage, a small amount of side information is computed and transmitted with the mixture. At a decoding Stage, when the sources are no longer available, the mixture is processed using the side information to recover the audio objects, thus greatly improving the quality of the estimates at a cost of additional bitrate which depends on the size of the side information. In this study, we compare six methods from the state of the art in terms of quality versus bitrate, and show that a good separation performance can be attained at competitive bitrates.
-
informed source separation through spectrogram coding and data embedding
Signal Processing, 2012Co-Authors: Antoine Liutkus, Roland Badeau, Laurent Girin, Jonathan Pinel, Gael RichardAbstract:We address the issue of underdetermined source separation in a particular informed configuration where both the sources and the mixtures are known during a so-called Encoding Stage. This knowledge enables the computation of a side-information which is small enough to be inaudibly embedded into the mixtures. At the decoding Stage, the sources are no longer assumed to be known, only the mixtures and the extracted side-information are processed for source separation. The proposed system models the sources as independent and locally stationary Gaussian processes (GP) and the mixing process as a linear filtering. This model allows reliable estimation of the sources through generalized Wiener filtering, provided their spectrograms are known. As these spectrograms are too large to be embedded in the mixtures, we show how they can be efficiently approximated using either Nonnegative Tensor Factorization (NTF) or image compression. A high-capacity embedding method is used by the system to inaudibly embed the separation side-information into the mixtures. This method is an application of the Quantization Index Modulation technique applied to the time-frequency coefficients of the mixtures and permits to reach embedding rates of about 250kbps. Finally, a study of the performance of the full system is presented.
Stephanie Caharel - One of the best experts on this subject based on the ideXlab platform.
-
other race and inversion effects during the structural Encoding Stage of face processing in a race categorization task an event related brain potential study
International Journal of Psychophysiology, 2011Co-Authors: Stephanie Caharel, Benoit Montalan, Emilie Fromager, Christian Bernard, Robert Lalonde, Rebai MohamedAbstract:To investigate the mechanisms underlying the other-race effect, in particular at what Stage of face processing differences between same-race (SR) and other-race (OR) stimuli occur, electrophysiological and behavioral data were obtained on Caucasian participants viewing photographs of Caucasian, Asian, and African faces in upright and inverted orientations. During a race categorization task, reaction times were faster for African than Asian faces, and both of them faster than Caucasian ones, independent of their orientation. The face-sensitive N170 component was low in amplitude for Caucasian, intermediate for Asian, and maximal for African faces. The face inversion effect was observed for all ethnic groups on N170 amplitudes, but was more evident for Caucasian faces. According to the perceptual expertise hypothesis, our results indicate that SR faces involve more configural/holistic processing OR faces.
-
perceptual interactions between visual processing of facial familiarity and emotional expression an event related potentials study during task switching
Neuroscience Letters, 2010Co-Authors: Arnaud Leleu, Stephanie Caharel, Benoit Montalan, Robert Lalonde, Julie Carre, Molka Snoussi, Alain Vom Hofe, Heidi Charvin, Mohamed RebaiAbstract:Models of face processing suggest that facial familiarity and expression processes involve independent visual systems. But under some conditions, the two processes interact, as when selective attention is solicited, and/or when a link is established between consecutive stimuli. To assess these assumptions during perceptual face processing, event-related potentials (ERPs) were used while subjects discriminated either familiarity or expression in a task-switching paradigm. Switched trials were designed with competitor priming, the unattended dimension being previously attended. The results indicate interactions appearing in the right hemisphere during the perceptual Encoding Stage (N170) when subjects processed either familiarity or expression during switched trials. These interactions gain both hemispheres during memory retrieval (P2) and in terms of accuracy. Altogether, these results confirm the critical role of the right hemisphere in perceiving faces and their expressions. Moreover, they suggest that familiarity and expression can interact in both directions.
Yao Wang - One of the best experts on this subject based on the ideXlab platform.
-
mpeg 4 rate control for multiple video objects
IEEE Transactions on Circuits and Systems for Video Technology, 1999Co-Authors: Anthony Vetro, Huifang Sun, Yao WangAbstract:This paper describes an algorithm which can achieve a constant bit rate when coding multiple video objects. The implementation is a nontrivial extension of the MPEG-4 rate control algorithm for single video objects which employs a quadratic rate quantizer model. The algorithm is organized into two Stages: a pre- and a post-Encoding Stage. In the pre-Encoding Stage, an initial target estimate is made for each object. Based on the buffer fullness, the total target is adjusted and then distributed proportional to the relative size, motion, and variance of each object. Based on the new individual targets and rate-quantizer relation for texture, appropriate quantization parameters are calculated. After each object is encoded, the model parameters for each object are updated, and if necessary, frames are skipped to ensure that the buffer does not overflow. A preframeskip control is exercised to avoid buffer overflow when the motion and shape information occupies a significant portion of the bit budget. The rate control algorithm switches between two operation modes so that the coder can reduce the spatial coding accuracy for an improved temporal resolution. A shape-coding control mechanism is also proposed, which provides a tradeoff between texture and shape coding accuracy. Overall, the algorithm is able to successfully achieve the target bit rate, effectively code arbitrarily shaped objects, and maintain a stable buffer level. These techniques have been adopted by the MPEG committee in July 1997 as part of the video verification model (VM8).
Roland Badeau - One of the best experts on this subject based on the ideXlab platform.
-
informed audio source separation a comparative study
European Signal Processing Conference, 2012Co-Authors: Antoine Liutkus, Roland Badeau, Laurent Girin, Laurent Daudet, Stanislaw Gorlow, Sylvain Marchand, Nicolas Sturmel, Shuhua Zhang, Gael RichardAbstract:The goal of source separation algorithms is to recover the constituent sources, or audio objects, from their mixture. However, blind algorithms still do not yield estimates of sufficient quality for many practical uses. Informed Source Separation (ISS) is a solution to make separation robust when the audio objects are known during a so-called Encoding Stage. During that Stage, a small amount of side information is computed and transmitted with the mixture. At a decoding Stage, when the sources are no longer available, the mixture is processed using the side information to recover the audio objects, thus greatly improving the quality of the estimates at a cost of additional bitrate which depends on the size of the side information. In this study, we compare six methods from the state of the art in terms of quality versus bitrate, and show that a good separation performance can be attained at competitive bitrates.
-
informed source separation through spectrogram coding and data embedding
Signal Processing, 2012Co-Authors: Antoine Liutkus, Roland Badeau, Laurent Girin, Jonathan Pinel, Gael RichardAbstract:We address the issue of underdetermined source separation in a particular informed configuration where both the sources and the mixtures are known during a so-called Encoding Stage. This knowledge enables the computation of a side-information which is small enough to be inaudibly embedded into the mixtures. At the decoding Stage, the sources are no longer assumed to be known, only the mixtures and the extracted side-information are processed for source separation. The proposed system models the sources as independent and locally stationary Gaussian processes (GP) and the mixing process as a linear filtering. This model allows reliable estimation of the sources through generalized Wiener filtering, provided their spectrograms are known. As these spectrograms are too large to be embedded in the mixtures, we show how they can be efficiently approximated using either Nonnegative Tensor Factorization (NTF) or image compression. A high-capacity embedding method is used by the system to inaudibly embed the separation side-information into the mixtures. This method is an application of the Quantization Index Modulation technique applied to the time-frequency coefficients of the mixtures and permits to reach embedding rates of about 250kbps. Finally, a study of the performance of the full system is presented.
