A Method to Analyze the Spatial Response of Informed Spatial Filters

Abstract:
Informed spatial filters (ISF) aim to capture multiple sound sources with a desired spatial response while attenuating the undesired signals. The desired spatial response is an arbitrary function, based on which directional gains at each time-frequency instant are computed. In this work, we propose a method to analyze the obtained spatial response at the output of the ISF and the influence of direction-ofarrival (DOA) estimation errors. The proposed method considers two simultaneously active sound sources, where one source is kept static at a reference position while the other source is moved across the DOA space by placing it at discrete DOA points. For each position of the moving source, we compute the average directional array gain. Through analysis with simulated speech signals, we show that with perfect knowledge of the source DOAs the obtained spatial response matches the desired one, and also demonstrate the adverse effects of DOA estimation errors.