Adaptive Array Reduction in Acoustic Beamforming (Virtual Presentation)

Acoustic beamforming is a widely used source localisation technique where an array of microphones is placed in the acoustic far-field to gather unique contributions of acoustic pressure waves. The spatial and temporal relationship of these pressure contributions are sensitive to the microphone array design. To date, most acoustic beamformers are constructed using a spiral-based array configuration, yet in recent years, a new technique for developing array patterns has emerged that unlocks flexibility and convenient customisation, yielding improved acoustic source imaging to its predecessors. These arrays are developed using an iterative microphone removal process, known as an array reduction method. A cost-function is developed that combines the penalty of spatial aliasing images, known as sidelobes, and the resolution of the acoustic source, known as the main lobe. Microphones are iteratively removed from a larger initial array to arrive at an array with a desired number of microphones, frequency range and spatial constraints. The use of array reduction method arrays has expanded into array designs for o set source locations, irregular areas, and the most recent advancement, array pairing. This paper provides a brief summary of the development of the array reduction techniques and some example results of its application.