Separation of target acoustic signals in a multi-transducer arrangement

• US 7,099,821 B2
• Filed: 07/22/2004
• Issued: 08/29/2006
• Est. Priority Date: 09/12/2003
• Status: Active Grant

• Current Assignee: Qualcomm, Inc., Regents of the University of California (University of California)
• Original Assignee: SoftMax Incorporated (Qualcomm, Inc.)
• Inventors: Visser, Erik, Lee, Te-Won
• Primary Examiner(s): Storm, Donald L.
• Application Number:
  US10/897,219
• Publication Number:
  US 20050060142A1
• Time in Patent Office: 768 Days
• Field of Search: None
• US Class Current: 704/226
• CPC Class Codes: G10L 2021/02161 Number of inputs available containing the signal or the noise to be suppressed
• CPC Class Codes: G10L 2021/02165 Two microphones, one receiving mainly the noise signal and the other one mainly the speech signal
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: G10L 21/0272 Voice signal separating
• CPC Class Codes: H04R 2430/25 Array processing for suppression of unwanted side-lobes in directivity characteristics, e.g. a blocking matrix
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

The present invention provides a process for separating a good quality information signal from a noisy acoustic environment. The separation process uses a set of at least two spaced-apart transducers to capture noise and information components. The transducer signals, which have both a noise and information component, are received into a separation process. The separation process generates one channel that is substantially only noise, and another channel that is a combination of noise and information. An identification process is used to identify which channel has the information component. The noise signal is then used to set process characteristics that are applied to the combination signal to efficiently reduce or eliminate the noise component. In this way, the noise is effectively removed from the combination signal to generate a good qualify information signal. The information signal may be, for example, a speech signal, a seismic signal, a sonar signal, or other acoustic signal.

Claims

1. A speech separation process, comprising:

positioning a plurality of microphones with respect to a speech source so that each respective microphone generates a signal having a speech component and a noise component in different mixing ratios;

receiving each of the signals generated by the microphones into a separation process;

separating the received signals into a first channel and a second channel, one of the channels providing a noise signal that is substantially noise components and the other channel providing a combination signal that is a combination of noise components and speech components;

identifying which of the first or second channels has the combination signal;

processing the combination signal with the noise signal;

generating a speech signal indicative of the speech from the speech source;

positioning the plurality of microphones in a first arrangement where a first microphone is closer to the speech source and a second microphone is farther from the speech source;

providing a set of filters within the separation process;

setting, for the first arrangement, each of the filters with respective filter coefficients to facilitate channel separation;

positioning the plurality of microphones in a second arrangement where the second microphone is closer to the speech source and the first microphone is farther from the speech source; and

rearranging, for the second arrangement, the filter coefficients for the set of filters.

2. The speech separation process according to claim 1, further including:

detecting a change from the first arrangement to the second arrangement.

3. The speech separation process according to claim 2 wherein the detecting step further includes making an energy comparison using one of the signals generated by the microphones.

4. The speech separation process according to claim 2 wherein the detecting step further includes making an energy comparison using the signals generated by the microphones to rearrange the filter coefficients.

5. The speech separation process according to claim 2 wherein the detecting step further includes using a-prior knowledge of the speech source location or characteristic.