US 12,267,653 B2
Noise reduction system, method of operating the system and use of the system
Marc Von Elling, Hamburg (DE)
Assigned to recalm GmbH, Hamburg (DE)
Filed by recalm GmbH, Hamburg (DE)
Filed on Jul. 12, 2023, as Appl. No. 18/221,002.
Claims priority of application No. 10 2022 118 018.2 (DE), filed on Jul. 19, 2022.
Prior Publication US 2024/0031752 A1, Jan. 25, 2024
Int. Cl. G10K 11/178 (2006.01); H04R 29/00 (2006.01)
CPC H04R 29/005 (2013.01) [G10K 11/1785 (2018.01); H04R 2400/01 (2013.01); H04R 2410/01 (2013.01); H04R 2499/13 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A noise reduction system for actively compensating background noise generated by a noise source in a noise reduction area in a passenger transport area of a vehicle, the system comprising:
a controller comprising hardware;
a reference sensor for detecting the background noise of the noise source;
a sound generator for generating anti-noise for superimposing the anti-noise with the background noise in the noise reduction area for active reduction of the background noise;
a monitor-microphone array having a plurality of monitor microphones, the monitor-microphone array being disposed adjacent to the noise reduction area and being configured to pick up background noise emitted by the noise source and anti-noise emitted by the sound generator, the monitor-microphone array comprises a direct monitor microphone;
wherein a virtual sensing algorithm is implemented in the controller, the controller being configured to:
estimate an error signal at a position of a virtual microphone, wherein the virtual microphone is located in the noise reduction area and the error signal is indicative of a difference between the background noise and the anti-noise at the position of the virtual microphone;
generate an anti-noise signal for driving the sound generator in that it generates the anti-noise;
calculate an average error signal, which is indicative of a difference between the background noise and the anti-noise at a position in the noise reduction area;
calculate the average error signal by further taking into account a direct residual signal of the direct monitor microphone; and
update parameters of the anti-noise unit based on the average error signal so as to minimize the average error signal.