Identification of Early Reflections using Sparse Recovery

• Applicant: Professor Dr.-Ing. Sascha Spors
• Subject Area: Acoustics
• Term: from 2016 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 309256691

• Final Report Year: 2021

Final Report Abstract

The main objective of this project was to investigate into techniques for the in-situ identification of early reflections from spatial room impulse responses. Hereby, identification included the localization of early reflections and the estimation of their frequency response. We aimed at identification over the full audio bandwidth as we targeted applications as e.g. auralization, numeric simulation and psychoacoustics. The localization of early reflections was addressed using the steered-response power technique. The spatial room impulse responses are decomposed into their plane wave contributions, followed by a search for points of maximum power in this representation. Traditionally the plane wave decomposition is computed using acoustic beamforming techniques basing on linear spatiotemporal transformations. Besides these traditional techniques, we investigated the applicability of sparse recovery techniques. However, due to the underlying properties of acoustic wave propagation these techniques were not so effective for the problem at hand. As alternative, a spatially bandlimited matched-filter beamformer was proposed which shows some desirable properties for broadband direction-of-arrival estimation from spatial room impulse responses. After localization of the early reflections, their frequency dependent properties were extracted by a null-streering beamformer and fractional-octave filterbank.

Publications

• Spatial Sub-Nyquist Sampling Layouts for Compact Microphone Arrays. In: German Annual Conference on Acoustics (DAGA), 2016
  Rettberg, Till; Spors, Sascha
  
• A comparison of modal and spatially matched-filter beamforming for rigid spherical microphone arrays in the context of data-based binaural synthesis. In: Journal of the Acoustical Society of America 141 (2017), June, Nr. 5, S. 3855
  Spors, Sascha; Rettberg, Till; Winter, Fiete
  
• On the Estimation of Acoustic Reflection Coefficients from In-Situ Measurements using a Spherical Microphone Array. In: German Annual Conference on Acoustics (DAGA), 2018
  Spors, Sascha; Rettberg, Till
  
• On the Detection Quality of Early Room Reflections using Compressive Sensing on Rigid Spherical Microphone Array Data. In: International Congress on Acoustics, 2019
  Schultz, Frank; Spors, Sascha
  
• Discrete Time Modeling of Regular Spherical Harmonic Expansion by using Band-Limited Step Functions. In: German Annual Conference on Acoustics (DAGA), 2020
  Hahn, Nara; Spors, Sascha