ASAP: An Azimuth-Priority Strip-Based Search Approach to Planar Microphone Array DOA Estimation in 3D

TL;DR

ASAP is a novel azimuth-priority search method for 3D planar microphone array DOA estimation that improves efficiency by focusing on azimuthal regions before refining elevation.

Contribution

The paper introduces ASAP, a two-stage azimuth-priority strip-based search approach that enhances real-time 3D DOA estimation for planar microphone arrays.

Findings

ASAP outperforms existing methods in simulation and real-world tests.

The approach significantly reduces computational load while maintaining accuracy.

ASAP effectively estimates azimuth and elevation in resource-constrained scenarios.

Abstract

Direction-of-arrival (DOA) estimation is an important task in microphone array processing and many downstream applications. The steered response power with phase transform (SRP-PHAT) method has been widely adopted for DOA estimation in recent years. However, accurate SRP-PHAT estimation in 3D scenarios requires evaluating steering responses over thousands of candidate directions, severely limiting real-time performance on resource-constrained platforms. This challenge becomes even more critical for planar arrays, which are widely used in robotics due to their structural simplicity. Motivated by the fact that azimuth estimation is usually more reliable than elevation estimation for most arrays, we propose ASAP, an azimuth-priority strip-based search approach to planar microphone array DOA estimation in 3D. In the first stage, ASAP performs coarse-to-fine region contraction within azimuthal strips to lock azimuth angles while retaining multiple maxima through spherical caps. In the second stage, it refines elevation along the great-circle arc between two close candidates. Extensive simulations and real-world experiments validate the efficiency and merits of the proposed method over existing approaches.