FIR-based symmetrical acoustic beamformer with a constant beamwidth

Rosen, Oren; Cohen, Israel; Malah, D.

doi:10.1016/j.sigpro.2016.07.019

Cited by 22 publications

(9 citation statements)

References 29 publications

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“…One can see that all the window-based methods can effectively keep the beamwidth constant over a wide frequency band. Compared with modified rectangular window [13], the other proposed windows can obtain much lower sidelobe levels.…”

Section: Experiments and Resultsmentioning

confidence: 99%

“…From Equation (11), in order to keep the beamwidth constant for varying frequency, the product Mf should remain constant, which means that the number of microphones should decrease as the frequency increases. To alleviate the beamwidth fluctuations, Rosen et al [13] proposed a modified rectangular window based on smoothing coefficients.…”

Section: Window-based Acoustic Beamformer With a Constant Beamwidthmentioning

confidence: 99%

“…The weights wm in [13] can be regarded as a kind of modified rectangular window:wm={1,−K<m<Kg,m=−K,m=K,(0<g<1)0,otherwise where 2K+1 is the number of activated microphones, and g is the smoothing coefficient.…”

Section: Window-based Acoustic Beamformer With a Constant Beamwidthmentioning

confidence: 99%

“…Recently, Rosen et al [13] proposed finite impulse response (FIR) based beamformers [14] with constant beamwidths. The main idea behind this approach is to change the effective array aperture in each frequency bin to maintain the beamwidth constant over the desired frequency band.…”

Section: Introductionmentioning

confidence: 99%

“…If we regard the coefficients of the FIR filter as a window function, then the beamformer is analogous to the discrete Fourier transform of the window. It can be shown that the FIR filter proposed in [13] is a kind of modified rectangular window, and it inspires us to use other kinds of windows. As a result, some standard window functions whose shapes are controlled by a single parameter can be directly used to obtain different beamwidths and sidelobe levels, e.g., a discrete prolate spheroidal sequences (DPSS) window can maximize the relative beamforming power that is concentrated in an angular region, and a Chebyshev window minimizes the beamwidth for a given sidelobe level.…”

Section: Introductionmentioning

confidence: 99%

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Window-Based Constant Beamwidth Beamformer

Tao

Cohen

Berdugo

et al. 2019

Sensors

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Beamformers have been widely used to enhance signals from a desired direction and suppress noise and interfering signals from other directions. Constant beamwidth beamformers enable a fixed beamwidth over a wide range of frequencies. Most of the existing approaches to design constant beamwidth beamformers are based on optimization algorithms with high computational complexity and are often sensitive to microphone mismatches. Other existing methods are based on adjusting the number of sensors according to the frequency, which simplify the design, but cannot control the sidelobe level. Here, we propose a window-based technique to attain the beamwidth constancy, in which different shapes of standard window functions are applied for different frequency bins as the real weighting coefficients of microphones. Thereby, not only do we keep the beamwidth constant, but we also control the sidelobe level. Simulation results show the advantages of our method compared with existing methods, including lower sidelobe level, higher directivity factor, and higher white noise gain.

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Section: Experiments and Resultsmentioning

confidence: 99%