초록

The invention is directed to a handsfree system for use in a vehicle comprising a microphone array with at least two microphones and a signal processing means wherein the signal processing means comprises the superdirective beamformer with fixed superdirective filters.

대표청구항 ▼

The invention claimed is: 1. A system for use in a vehicle comprising: a microphone array with at least two microphones; and a superdirective beamformer with fixed superdirective filters; where the superdirective beamformer is a regularized superdirective beamformer using a finite regularization pa

The invention claimed is: 1. A system for use in a vehicle comprising: a microphone array with at least two microphones; and a superdirective beamformer with fixed superdirective filters; where the superdirective beamformer is a regularized superdirective beamformer using a finite regularization parameter μ that is frequency dependent. 2. A system according to claim 1 where each superdirective filter results from an iterative design based on a predetermined maximum susceptibility. 3. A system according to claim 1 where each superdirective filter comprises a filter in the time domain. 4. A system according to claim 1 where the signal processing means further comprises at least one inverse filter for adjusting a microphone transfer function. 5. A system according to claim 4 where the at least one inverse filter comprises a warped inverse filter. 6. A system according to claim 4 where each inverse filter comprises an approximate inverse of a non-minimum phase filter. 7. A system according to claim 4 where each inverse filter is combined with a superdirective filter of the beamformer. 8. A system according to claim 1 where the beamformer comprises the structure of a generalized sidelobe canceller (GSC). 9. A system according to claim 1 where the beamformer comprises a minimum variance distortionless response (MVDR) beamformer. 10. A system according to claim 1 where the microphone array comprises at least two microphones arranged in an endfire orientation with respect to a first position. 11. A system according to claim 10 where the microphone array comprises at least two microphones arranged in endfire orientation with respect to a second position. 12. A system according to claim 11 where the at least two microphones in the first endfire orientation and the at least two microphones in the second endfire orientation comprise a microphone in common. 13. A system according to claim 1 where the microphone array comprises at least two subarrays. 14. A system according to claim 13 where the at least two subarrays comprise at least one microphone in common. 15. A system according to claim 1 further comprising a frame where each microphone of the microphone array is arranged in a predetermined position in or on the frame. 16. A system according to claim 15 where the predetermined position comprises a fixed position in or on the frame. 17. A system according to claim 1 where at least one microphone comprises a directional microphone. 18. A system according to claim 17 where the directional microphone comprises a directional microphone with a cardioid characteristic. 19. A system according to claim 17 where the directional microphone comprises a differential microphone. 20. A system according to claim 1 comprising a vehicle coupled to the microphone and the beamformer. 21. A system for use in a vehicle comprising: a microphone array with at least two microphones and a superdirective beamformer having fixed superdirective filters; where the superdirective beamformers are configured with a predetermined susceptibility that is based on a relative error of the microphone array; where the relative error of the microphone array is a sum of mean square error of transfer properties of each microphone in the microphone array and a gaussian error with zero mean of microphone positions. 22. A system according to claim 21 where at least two microphones in the microphone array are arranged in an endfire orientation with respect to a first position. 23. A system according to claim 22 where at least two microphones in the microphone array are arranged in an endfire orientation with respect to a second position. 24. A system according to claim 21 where at least one microphone comprises a directional microphone. 25. A system according to claim 24 where the directional microphone comprises a directional microphone with a cardio characteristic. 26. A system according to claim 24 where the directional microphone comprises a differential microphone.