Abstract
Active acoustic noise attenuation over a sizable space is a challenging problem in signal processing. The noise attenuation performance of feedforward active noise control (ANC) relies on the preciseness of a reference signal of a primary noise field. To capture the precise reference signal for controlling a sizable space, a large number of reference microphones are required, which reduces system viability. In this study, we exploit an efficient representation of the reference signal in spherical harmonic (SH) domain by utilizing the inherent sparseness of the noise field. The main contributions of this work are as follows. (1) A general reference microphone geometry can be used. The implementation difficulty in the array structure, which is recognized as the common issue of SH-domain signal processing, e.g., use of a fully surrounding spherical array, is reduced by using the fields translation based on the addition theorem. (2) The accuracy of low-frequency signal decomposition is improved. The low accuracy of low-frequency signal decomposition in compressive sensing (CS), which is commonly reported in the literature, is improved by applying signal representation in SH domain. (3) System robustness is increased. The robustness of the system is increased by considering a noise source spatial distribution of both the interior and exterior sound fields, which is not possible in the case of a general signal representation in SH domain. Experimental results indicate that the noise attenuation performance of our proposed method exceeds that of existing solutions. The flexibility of the array structure is also increased, which leads to a more feasible practical system setup.
Highlights
A CTIVE noise control is a technique by which a noise field is attenuated by generating an antinoise field using secondary sources
We proposed the reference signal reconstruction algorithm for spherical harmonic (SH)-domain feedforward active noise control (ANC)
We assumed that the primary noise field can be represented as a sum of a sparse set of point sources and plane waves and adopted the compressive sensing (CS) approach to decompose the noise field into them
Summary
A CTIVE noise control is a technique by which a noise field is attenuated by generating an antinoise field using secondary sources. Harmonic-domain-based ANC methods, which decompose signals into harmonic basis functions, e.g., spherical harmonic (SH) functions, were proposed [7]–[11] The advantages of this approach are that the sound field can be controlled in terms of a region rather than points and a fast convergence can be achieved by uniformly placing the microphones and secondary sources on an applicable surface, e.g., a sphere. We previously introduced the CS approach to reduce the number of reference microphones and showed that noise can be attenuated by using a number of microphones that is smaller than a number required by the spatial Nyquist theory [23] One limitation of this approach is that the reproduction accuracy at low frequencies is limited since CS is based on an assumption, that the columns of a sensing matrix are mutually incoherent [24]. System robustness is increased for the aforementioned problem associated with the composite noise field of outgoing and incoming sound fields
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call