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Efficient Finite Element Approach for Structural-Acoustic Applications including 3D modelling of Sound Absorbing Porous MaterialsRumpler, Romain January 2012 (has links)
In the context of interior noise reduction, the present work aims at proposing Finite Element (FE) solution strategies for interior structural-acoustic applications including 3D modelling of homogeneous and isotropic poroelastic materials, under timeharmonic excitations, and in the low frequency range. A model based on the Biot-Allard theory is used for the poroelastic materials, which is known to be very costly in terms of computational resources. Reduced models offer the possibility to enhance the resolution of such complex problems. However, their applicability to porous materials remained to be demonstrated.First, this thesis presents FE resolutions of poro-elasto-acoustic coupled problems using modal-based approaches both for the acoustic and porous domains. The original modal approach proposed for porous media, together with a dedicated mode selection and truncation procedure, are validated on 1D to 3D applications.In a second part, modal-reduced models are combined with a Padé approximants reconstruction scheme in order to further improve the efficiency.A concluding chapter presents a comparison and a combination of the proposed methods on a 3D academic application, showing promising performances. Conclusions are then drawn to provide indications for future research and tests to be conducted in order to further enhance the methodologies proposed in this thesis. / Dans le contexte de lutte contre les nuisances sonores, cette thèse porte sur le développement de méthodes de résolution efficaces par éléments finis, pour des problèmes de vibroacoustique interne avec interfaces dissipatives, dans le domaine des basses fréquences. L’étude se limite à l’utilisation de solutions passives telles que l’intégration de matériaux poreux homogènes et isotropes, modélisés par une approche fondée sur la théorie de Biot-Allard. Ces modèles étant coûteux en terme de résolution, un des objectifs de cette thèse est de proposer une approche modale pour la réduction du problème poroélastique, bien que l’adéquation d’une telle approche avec le comportement dynamique des matériaux poreux soit à démontrer.Dans un premier temps, la résolution de problèmes couplés élasto-poro-acoustiques par sous-structuration dynamique des domaines acoustiques et poreux est établie. L’approche modale originale proposée pour les milieux poroélastiques, ainsi qu’une procédure de sélection des modes significatifs, sont validées sur des exemples 1D à 3D.Une deuxième partie présente une méthode combinant l’utilisation des modèles réduits précédemment établis avec une procédure d’approximation de solution par approximants de Padé. Il est montré qu’une telle combinaison offre la possibilité d’accroître les performances de la résolution (allocation mémoire et ressources en temps de calcul).Un chapitre dédié aux applications permet d’évaluer et comparer les approches sur un problème académique 3D, mettant en valeur leurs performances encourageantes. Afin d’améliorer les méthodes établies dans cette thèse, des perspectives à ces travaux de recherche sont apportées en conclusion. / <p>QC 20120224</p> / FP6 Marie-Curie Smart Structures / FP7 Marie-Curie Mid-Frequency
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Audio editing in the time-frequency domain using the Gabor Wavelet TransformHammarqvist, Ulf January 2011 (has links)
Visualization, processing and editing of audio, directly on a time-frequency surface, is the scope of this thesis. More precisely the scalogram produced by a Gabor Wavelet transform is used, which is a powerful alternative to traditional techinques where the wave form is the main visual aid and editting is performed by parametric filters. Reconstruction properties, scalogram design and enhancements as well audio manipulation algorithms are investigated for this audio representation.The scalogram is designed to allow a flexible choice of time-frequency ratio, while maintaining high quality reconstruction. For this mean, the Loglet is used, which is observed to be the most suitable filter choice. Re-assignmentare tested, and a novel weighting function using partial derivatives of phase is proposed. An audio interpolation procedure is developed and shown to perform well in listening tests.The feasibility to use the transform coefficients directly for various purposes is investigated. It is concluded that Pitch shifts are hard to describe in the framework while noise thresh holding works well. A downsampling scheme is suggested that saves on operations and memory consumption as well as it speeds up real world implementations significantly. Finally, a Scalogram 'compression' procedure is developed, allowing the caching of an approximate scalogram.
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Kalman filtering for computer music applicationsBenning, Manjinder 27 August 2007 (has links)
This thesis discusses the use of Kalman filtering for noise reduction in a 3-D gesture-
based computer music controller known as the Radio Drum and for real-time tempo
tracking of rhythmic and melodic musical performances. The Radio Drum noise
reduction Kalman filter is designed based on previous research in the field of target
tracking for radar applications and prior knowledge of a drummer’s expected gestures
throughout a performance. In this case we are seeking to improve the position
estimates of a drum stick in order to enhance the expressivity and control of the
instrument by the performer. Our approach to tempo tracking is novel in that a multi-
modal approach combining gesture sensors and audio in a late fusion stage lead to
higher accuracy in the tempo estimates.
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Méthodes avancées de traitement de la parole et de réduction de bruit pour les terminaux mobiles / Advanced methods of speech processing and noise reduction for mobile devicesMai, Van Khanh 09 March 2017 (has links)
Cette thèse traite d'un des problèmes les plus stimulants dans le traitement de la parole concernant la prothèse auditive, où seulement un capteur est disponible avec de faibles coûts de calcul, de faible utilisation d'énergie et l'absence de bases de données. Basée sur les récents résultats dans les deux estimations statistiques paramétriques et non-paramétriques, ainsi que la représentation parcimonieuse. Cette étude propose quelques techniques non seulement pour améliorer la qualité et l'intelligibilité de la parole, mais aussi pour s'attaquer au débruitage du signal audio en général.La thèse est divisée en deux parties ; Dans la première partie, on aborde le problème d'estimation de la densité spectrale de puissance du bruit, particulièrement pour le bruit non-stationnaire. Ce problème est une des parties principales du traitement de la parole du mono-capteur. La méthode proposée prend en compte le modèle parcimonieux de la parole dans le domaine transféré. Lorsque la densité spectrale de puissance du bruit est estimée, une approche sémantique est exploitée pour tenir compte de la présence ou de l'absence de la parole dans la deuxième partie. En combinant l'estimation Bayésienne et la détection Neyman-Pearson, quelques estimateurs paramétriques sont développés et testés dans le domaine Fourier. Pour approfondir la performance et la robustesse de débruitage du signal audio, une approche semi-paramétrique est considérée. La conjointe détection et estimation peut être interprétée par Smoothed Sigmoid-Based Shrinkage (SSBS). Ainsi, la méthode Bloc-SSBS est proposée afin de prendre en compte les atomes voisinages dans le domaine temporel-fréquentiel. De plus, pour améliorer fructueusement la qualité de la parole et du signal audio, un estimateur Bayésien est aussi dérivé et combiné avec la méthode Bloc-SSBS. L'efficacité et la pertinence de la stratégie dans le domaine transformée cosinus pour les débruitages de la parole et de l'audio sont confirmées par les résultats expérimentaux. / This PhD thesis deals with one of the most challenging problem in speech enhancement for assisted listening where only one micro is available with the low computational cost, the low power usage and the lack out of the database. Based on the novel and recent results both in non-parametric and parametric statistical estimation and sparse representation, this thesis work proposes several techniques for not only improving speech quality and intelligibility and but also tackling the denoising problem of the other audio signal. In the first major part, our work addresses the problem of the noise power spectrum estimation, especially for non-stationary noise, that is the key part in the single channel speech enhancement. The proposed approach takes into account the weak-sparseness model of speech in the transformed model. Once the noise power spectrum has been estimated, a semantic road is exploited to take into consideration the presence or absence of speech in the second major part. By applying the joint of the Bayesian estimator and the Neyman-Pearson detection, some parametric estimators were developed and tested in the discrete Fourier transform domain. For further improve performance and robustness in audio denoising, a semi-parametric approach is considered. The joint detection and estimation can be interpreted by Smoothed Sigmoid-Based Shrinkage (SSBS). Thus, Block-SSBS is proposed to take into additionally account the neighborhood bins in the time-frequency domain. Moreover, in order to enhance fruitfully speech and audio, a Bayesian estimator is also derived and combined with Block-SSBS. The effectiveness and relevance of this strategy in the discrete Cosine transform for both speech and audio denoising are confirmed by experimental results.
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Novel image processing algorithms and methods for improving their robustness and operational performanceRomanenko, Ilya January 2014 (has links)
Image processing algorithms have developed rapidly in recent years. Imaging functions are becoming more common in electronic devices, demanding better image quality, and more robust image capture in challenging conditions. Increasingly more complicated algorithms are being developed in order to achieve better signal to noise characteristics, more accurate colours, and wider dynamic range, in order to approach the human visual system performance levels.
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Efficient finite element approach for structural-acoustic applicationns including 3D modelling of sound absorbing porous materials / Modélisation de problèmes de vibro-acoustique interne avec traitement poroélastique : approche efficace par la méthode des éléments finisRumpler, Romain 13 March 2012 (has links)
Dans le contexte de lutte contre les nuisances sonores, cette thèse porte sur le développement de méthodes de résolution efficaces par éléments finis, pour des problèmes de vibroacoustique interne avec interfaces dissipatives, dans le domaine des basses fréquences. L’étude se limite à l’utilisation de solutions passives telles que l’intégration de matériaux poreux homogènes et isotropes, modélisés par une approche fondée sur la théorie de Biot-Allard. Ces modèles étant coûteux en terme de résolution, un des objectifs de cette thèse est de proposer une approche modale pour la réduction du problème poroélastique, bien que l’adéquation d’une telle approche avec le comportement dynamique des matériaux poreux soit à démontrer. Dans un premier temps, la résolution de problèmes couplés élasto-poro-acoustiques par sous-structuration dynamique des domaines acoustiques et poreux est établie. L’approche modale originale proposée pour les milieux poroélastiques, ainsi qu’une procédure de sélection des modes significatifs, sont validées sur des exemples 1D à 3D. Une deuxième partie présente une méthode combinant l’utilisation des modèles réduits précédemment établis avec une procédure d’approximation de solution par approximants de Padé. Il est montré qu’une telle combinaison offre la possibilité d’accroître les performances de la résolution (allocation mémoire et ressources en temps de calcul). Un chapitre dédié aux applications permet d’évaluer et comparer les approches sur un problème académique 3D, mettant en valeur leurs performances encourageantes. Afin d’améliorer les méthodes établies dans cette thèse, des perspectives à ces travaux de recherche sont apportées en conclusion. / In the context of interior noise reduction, the present work aims at proposing Finite Element (FE) solution strategies for interior structural-acoustic applications including 3D modelling of homogeneous and isotropic poroelastic materials, under timeharmonic excitations, and in the low frequency range. A model based on the Biot-Allard theory is used for the poroelastic materials, which is known to be very costly in terms of computational resources. Reduced models offer the possibility to enhance the resolution of such complex problems. However, their applicability to porous materials remained to be demonstrated.First, this thesis presents FE resolutions of poro-elasto-acoustic coupled problems using modal-based approaches both for the acoustic and porous domains. The original modal approach proposed for porous media, together with a dedicated mode selection and truncation procedure, are validated on 1D to 3D applications.In a second part, modal-reduced models are combined with a Padé approximants reconstruction scheme in order to further improve the efficiency.A concluding chapter presents a comparison and a combination of the proposed methods on a 3D academic application, showing promising performances. Conclusions are then drawn to provide indications for future research and tests to be conducted in order to further enhance the methodologies proposed in this thesis.
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Akustické mikroklima nevýrobních objektů / Acoustic microclimate non-manufacturing buildingsJelínek, Ondřej January 2013 (has links)
This master´s thesis focuses on effect of acoustic microclimate in non-production buildings to human. Within elaboration this topic was made measurment acoustic power level and created protocols by valid technical standards and law. I dedicate to damping noise and aerodynamic noise in airconditioning in part topic analysis. The part aplication on real object deal with assessment current status and draft measure for improve acoustic ratio in laboratories in center of research located in Brno. That includes describe of air-cndition unit and development two variants and their rating.
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Objektivní měření a potlačování šumu v hudebním signálu / Objective assessment and reduction of noise in musical signalRášo, Ondřej January 2013 (has links)
The dissertation thesis focuses on objective assessment and reduction of disturbing background noise in a musical signal. In this work, a new algorithm for the assessment of background noise audibility is proposed. The listening tests performed show that this new algorithm better predicts the background noise audibility than the existing algorithms do. An advantage of this new algorithm is the fact that it can be used even in the case of a general audio signal and not only musical signal, i.e. in the case when the audibility of one sound on the background of another sound is assessed. The existing algorithms often fail in this case. The next part of the dissertation thesis deals with an adaptive segmentation scheme for the segmentation of long-term musical signals into short segments of different lengths. A new adaptive segmentation scheme is then introduced here. It has been shown that this new adaptive segmentation scheme significantly improves the subjectively perceived quality of the musical signal from the output of noise reduction systems which use this new adaptive segmentation scheme. The quality improvement is better than that achieved by other segmentation schemes tested.
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Rozpoznávání obrazů pro ovládání robotické ruky / Image recognition for robotic handLabudová, Kristýna January 2017 (has links)
This thesis concerns with processing of embedded terminals’ images and their classification. There is problematics of moire noise reduction thought filtration in frequency domain and the image normalization for further processing analyzed. Keypoints detectors and descriptors are used for image classification. Detectors FAST and Harris corner detector and descriptors SURF, BRIEF and BRISK are emphasized as well as their evaluation in terms of potential contribution to this work.
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Creative development of lightweight façade constructions in modular housing : The struggle to shut out the noise of the worldAlbihn, Johan January 2022 (has links)
Modular construction of housing is an industry on the rise. The prefabrication of construction modules gives a greater control over material consumption, promotes standardization, and lessens the disturbance during the construction time in the field. Lindbäcks Bygg AB prefabricates housing modules in their factory at Haraholmen, Piteå. The modules are then transported to construction sites all over the country and assembled. Lindbäcks Bygg AB has made the design choice to focus on lightweight wooden constructions for their modules, which comes with its own set of challenges. The urban densification of our city regions has led to more and more residential building being planned and constructed in areas that are submitted to high noise levels from surrounding traffic. This puts a great strain on the sound reduction of the building’s façade wall construction, something that has proven to be a problem with lightweight wooden walls. The aim of this master thesis project has been to test different solutions for lightweight façade wall constructions, and to ultimately find one or more solution that meet the requirements of the Swedish standards and regulations, as well as the needs of the tenants, and that can be implemented by Lindbäcks Bygg AB for manufacturing and assembly. The project has therefore been carried out in two parts, one theoretical and one practical. The theoretical part has verified the problem with traffic noise levels in residential buildings and identified the critical areas of the current façade construction. The theoretical work led to a list of defining factors for the sound reduction, which in turn worked as a basis for the ideation process. As a result, the theoretical part led to a number of different construction concepts for façade walls. The concepts were first tested theoretically through modelling and calculation, and verified with the acousticians at Tyréns Sverige AB and the engineers of Lindbäcks Bygg AB. The most promising concepts were sent on to be manufactured. The practical part of this master thesis project was carried out mainly as acoustical measurements and the subsequent analysis, where the manufactured façade wall constructions were mounted on a free-standing module. The result of the practical part, and of the master thesis project, were four different façade wall constructions that met the requirements for noise reduction, which were presented to Lindbäcks Bygg AB and Tyréns Sverige AB. The construction most easily implemented is a construction with an airgap between the wall panels, and this construction will now have to be structurally verified and adapted for the factory, before being utilized in future building projects. / Modulärt byggande av bostäder är en bransch på frammarsch. Prefabricering av byggnadsmoduler ger en större kontroll över materialåtgången, främjar standardisering och minskar störningarna under byggtiden i fält. Lindbäcks Bygg AB prefabricerar bostadsmoduler i sin fabrik på Haraholmen, Piteå. Modulerna transporteras sedan till byggarbetsplatser över hela landet och monteras till bostadskomplex. Lindbäcks Bygg AB har gjort designvalet att fokusera på lätta träkonstruktioner för sina moduler, vilket kommer med sin egen uppsättning utmaningar. Förtätningen av våra stadsregioner har lett till att allt mer bostadsbyggande planeras och uppförs i områden som utsätts för höga bullernivåer från omgivande trafik. Detta utsätter byggnadens fasadväggskonstruktion för en stor akustisk belastning, något som har visat sig vara ett problem med lätta träväggar. Syftet med detta examensarbete har varit att testa olika lösningar för lätta fasadväggskonstruktioner, och att i slutändan hitta en eller flera lösningar som uppfyller kraven i svenska standarder och föreskrifter samt hyresgästernas behov, och som kan implementeras av Lindbäcks Bygg AB för tillverkning och montering. Projektet har därför genomförts i två delar, en teoretisk och en praktisk. Den teoretiska delen har verifierat problemet med trafikbullernivåer i bostadshus och identifierat kritiska områden i den nuvarande fasadkonstruktionen. Det teoretiska arbetet ledde fram till en lista med kritiska faktorer för ljudreduktionen, som i sin tur fungerade som grund för designprocessen. Som ett resultat ledde den teoretiska delen till en rad olika konstruktionskoncept för fasadväggar. Koncepten testades först teoretiskt genom modellering och beräkning, och verifierades av akustikerna på Tyréns Sverige AB och ingenjörerna på Lindbäcks Bygg AB. De mest lovande koncepten skickades vidare för tillverkning. Den praktiska delen av detta examensarbete genomfördes främst som akustiska mätningar och efterföljande analys, där de tillverkade fasadväggkonstruktionerna monterades på en fristående modul. Resultatet av den praktiska delen, och av examensarbetet, blev fyra olika fasadväggskonstruktioner som uppfyller kraven för ljudreduktion, vilka presenterades för Lindbäcks Bygg AB och Tyréns Sverige AB. Den konstruktion som är enklast att implementera är en konstruktion med luftspalt mellan väggpanelerna, och denna konstruktion kommer nu att behöva verifieras med avseende på ex. hållfasthet och anpassas för fabriken, innan den kan användas i framtida byggprojekt.
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