Acoustic Array Systems

10

Concluding Remarks and Future Perspectives

In closing the book, we summarize the results of acoustic array systems in this chapter. In addition, we also suggest several research perspectives that can be explored further in the future.

10.1 Concluding Remarks

This book presents a comprehensive overview of microphone array technologies encompassing all aspects from the theory to implementation. Farfield and nearfield sound imaging techniques have been addressed in this book. Farfield sound image covers two aspects. First, optimized planar array deployment for source imaging has been examined. Global optimization algorithms have been developed to facilitate the search for the optimized microphone deployment. The SA algorithm and the combined SA–IBMC algorithm prove effective in finding the optimal deployment. For farfield array with sparse deployment in which inter-element spacing is large, random deployment with optimal weights is crucial to avoid grating lobes. As predicted by the conventional wisdom, the optimized random sparse array has excellent beam pattern with a unique main-lobe. Second, several acoustic imaging algorithms including DAS, TR, MVDR, MUSIC and an inverse filter-based method SIMO–ESIF have been developed to estimate DOA. The resolution of noise image in low frequencies is worse than in high frequencies with random array deployment. The SIMO–ESIF approach estimate DOA using a URA without grating lobe problems. As expected, the high-resolution methods such as ...