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Dereverberation systems design for room acoustics / Ahfir, Maâmar 

Public ISBD Titre : Dereverberation systems design for room acoustics Type de document : texte imprimé Auteurs : Ahfir, Maâmar, Auteur ; Berkani, Daoud, Directeur de thèse Editeur : [S.l.] : [s.n.] Année de publication : 2008 Importance : 48 f. Présentation : ill. Format : 30 cm. Accompagnement : 1 CD-ROM. Note générale : Thèse de Doctorat: Electronique: Alger, Ecole Nationale Polytechnique: 2008 Bibliogr. [6] f. Annexe [18] f Langues : Anglais (eng) Mots-clés : Homomorphic  method  ;  Inverse  filtering  ;  Partial  equalization  ;  Speech  dereverberation  ;  DSP  DFT  RIF Index. décimale : D000208 Résumé : Partial equalization techniques are very interesting because they simultaneously allow reduction of reverberation effect and implementation complexity of FIR inverse filters. In this work, two different techniques for dereverberation systems design based on partial equalization for room acoustics have been proposed. The Homomorphic method is used to design stable minimum-phase inverse filters (equalizers) for non-minimum-phase acoustic impulse responses corresponding to small and large rooms. In the first proposed approach, some of the dominant poles of the inverse filter transfer function are replaced by new ones before carrying out the inverse DFT. Results for an impulse response measured in the car interior show that by using the modified version we can control the sound quality more precisely than when using the standard method. In the second approach, an iterative simple smoothing is applied to the original impulse response of a large room before its inversion. Corresponding time reduced impulse responses are derived which conform to perceptual principles. The smoothed impulse responses are then used to design equalization filters. Simulation results for a reverberant audio-conferencing room have been validated using listening tests on Texas Instruments DSP board. Dereverberation systems design for room acoustics [texte imprimé] / Ahfir, Maâmar, Auteur ; Berkani, Daoud, Directeur de thèse . - [S.l.] : [s.n.], 2008 . - 48 f. : ill. ; 30 cm. + 1 CD-ROM. Thèse de Doctorat: Electronique: Alger, Ecole Nationale Polytechnique: 2008 Bibliogr. [6] f. Annexe [18] f Langues : Anglais (eng) Mots-clés : Homomorphic  method  ;  Inverse  filtering  ;  Partial  equalization  ;  Speech  dereverberation  ;  DSP  DFT  RIF Index. décimale : D000208 Résumé : Partial equalization techniques are very interesting because they simultaneously allow reduction of reverberation effect and implementation complexity of FIR inverse filters. In this work, two different techniques for dereverberation systems design based on partial equalization for room acoustics have been proposed. The Homomorphic method is used to design stable minimum-phase inverse filters (equalizers) for non-minimum-phase acoustic impulse responses corresponding to small and large rooms. In the first proposed approach, some of the dominant poles of the inverse filter transfer function are replaced by new ones before carrying out the inverse DFT. Results for an impulse response measured in the car interior show that by using the modified version we can control the sound quality more precisely than when using the standard method. In the second approach, an iterative simple smoothing is applied to the original impulse response of a large room before its inversion. Corresponding time reduced impulse responses are derived which conform to perceptual principles. The smoothed impulse responses are then used to design equalization filters. Simulation results for a reverberant audio-conferencing room have been validated using listening tests on Texas Instruments DSP board.

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité	Spécialité	Etat_Exemplaire
D000208B	D000208	Papier + ressource électronique	Bibliothèque Annexe	Thèse de Doctorat	Disponible	Electronique	Consultation sur place/Téléchargeable
D000208A	D000208	Papier + ressource électronique	Bibliothèque centrale	Thèse de Doctorat	Disponible	Electronique	Consultation sur place/Téléchargeable

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