Circuit arrangement and method for detecting and improving a speech component in an audio signal

• US 8,005,672 B2
• Filed: 10/11/2005
• Issued: 08/23/2011
• Est. Priority Date: 10/08/2004
• Status: Expired due to Fees

• Current Assignee: Entropic Communications Incorporated (Maxlinear Incorporated)
• Original Assignee: Trident Microsystems Limited (Avnet Incorporated)
• Inventors: Mueller, Stefan, Vierthaler, Matthias, Luecking, Dieter, Pfister, Florian
• Primary Examiner(s): Dorvil; Richemond
• Assistant Examiner(s): Borsetti; Greg
• Application Number:
  US11/249,020
• Publication Number:
  US 20060080089A1
• Time in Patent Office: 2,142 Days
• Field of Search: 704/233, 704/E11.003, 704/E21.002
• US Class Current: 704/233
• CPC Class Codes: G10L 21/0364 for improving intelligibility

Abstract

An audio processing system includes a speech detector that receives and processes an audio input signal to determine if the input signal includes components indicative of speech, and provides a control signal indicative of whether or not the audio input signal includes speech. A speech processing device receives the audio input signal and processes the audio input signal to improve its quality if the control signal indicates that the audio input signal includes speech.

Claims

1. An audio signal processing circuit, comprising:

a speech detector that receives a multi-component audio signal including at least a left signal component and a right signal component, and provides a control signal indicative of whether the received audio signal contains speech, wherein the speech detector combines the left and the right signal components to provide a combined signal component and comprises a processing device that detects speech by comparing and processing the combined signal component, the left signal component and the right signal component; and

a speech processor that receives the multi-component audio signal and the control signal, and modifies the received multi-component audio signal if the control signal indicates that the received multi-component audio signal contains speech and provides a processed modified multi-component audio signal that includes (A) a modified left signal component that comprises the sum of (i) the left signal component multiplied by a first factor K1 and (ii) the right signal component multiplied by a second factor K2, and (B) a modified right signal component that comprises the sum of (i) the left signal component multiplied by a third factor K3 and (ii) the right signal component multiplied by a fourth factor K4, and provides the received multi-component audio signal if the control signal indicates that the received audio signal does not contain speech, where the values for K1, K2, K3 and K4 are set as a function of the control signal value;

where the speech processor comprises a speech improvement device configured to modify the speech component of the received audio signal.

2. The circuit of claim 1, where the speech detector compares a range of detected speech components to a threshold value and outputs the control signal depending on the result of the comparison.

3. The circuit of claim 2, where the speech detector receives at least one parameter (V) for variable controlling the speech detector with respect to at least one of a range of speech components being detected and a frequency range of speech components being detected.

4. The circuit of claim 1, where the speech detector comprises a correlation device that operates on the audio signal to provide the control signal.

5. The circuit of claim 1, where the multi-component audio signal is one of a stereo audio signal comprising the left and the right signal components, a 3D stereo audio signal comprising the left and the right signal components, and a center signal component, and a surround audio signal comprising the left and the right signal components, the center signal component, and a surround signal component.

6. The circuit of claim 5, where the speech detector comprises a direction determining device for determining at least one of a direction and a distance of common signal components of the different signal components (L, R, C, S).

7. The circuit of claim 1, where the speech detector comprises a frequency-energy detector for determining signal energy in a voice frequency range in relation to signal energy of the audio signal.

8. The circuit of claim 7, where the speech detector is at least one of configured and controlled to output the control signal depending on results of at least one of a comparison device, a direction determining device and both a frequency-energy detector and a correlation device.

9. The circuit of claim 1, where a frequency response is determined by at least one of a Finite Impulse Response filter and an Infinite Impulse Response filter.

10. The circuit of claim 1, where the signal components of the audio signal are separated by a matrix.

11. The circuit of claim 1, wherein the function is linear and constant.

12. The circuit of claim 1, wherein the function has a hysteresis.

13. A speech detecting and processing method for use with an audio signal processor, comprising:

receiving a multi-component audio signal including a left signal component and a right signal component;

combining the left and the right signal components to obtain a combined signal component;

detecting speech components in the received audio signal with the audio signal processor by at least one comparing to each other and processing with each other the left signal component, the right signal component and the combined signal component, and providing a control signal indicative of if the multi-component audio signal contains speech;

processing the received audio signal with the audio signal processor if the control signal indicates that the received audio signal contains speech by providing a processed modified multi-component audio signal that includes (A) a modified left signal component that comprises the sum of (i) the left signal component multiplied by a first factor K1 and (ii) the right signal component multiplied by a second factor K2, and (B) a modified right signal component that comprises the sum of (i) the left signal component multiplied by a third factor K3 and (ii) the right signal component multiplied by a fourth factor K4, and provides the received multi-component audio signal if the control signal indicates that the received audio signal does not contain speech, where the values for K1, K2, K3 and K4 are set as a function of the control signal value.

14. The method of claim 13, where the range of detected speech components is compared to a threshold value.

15. The method of claim 14, where the detection is carried out with regard to at least one of a range of speech components to be detected and a frequency range of the speech components to be detected and is adjustable by at least one variable parameter, the threshold value.

16. The method of claim 15, where at least one of a cross correlation and an autocorrelation of at least one of the multi-component audio signal, the left signal component, the right signal component and the combined signal component of the audio signal is performed.

17. The method of claim 13, where the combined signal component, the left signal component and the right signal component are at least one of compared and processed with respect to common speech components in the different audio signal components, to determine at least one of a direction and a distance of the common signal components.

18. The method of claim 17, where energy of the audio signal is determined within a voice frequency range (f1, . . . f2) in relation to energy of the audio signal in a different frequency range.

19. An audio processing system, comprising:

a speech detector that receives and processes a multi-component audio input signal including at least a left signal component and a right signal component to obtain a combined signal component, and comprises a processing device for at least one of comparing and processing the combined signal component, the left signal component and the right signal component among each another to determine if the audio input signal includes components indicative of speech, and provides a control signal indicative of whether or not the audio input signal includes speech;

a speech processing device that receives the audio input signal and processes speech components of the audio input signal to improve its quality if the control signal indicates that the audio input signal includes speech and provides a processed modified multi-component audio signal that includes (A) a modified left signal component that comprises the sum of (i) the left signal component multiplied by a first factor K1 and (ii) the right signal component multiplied by a second factor K2, and (B) a modified right signal component that comprises the sum of (i) the left signal component multiplied by a third factor K3 and (ii) the right signal component multiplied by a fourth factor K4, and provides the received multi-component audio signal if the control signal indicates that the received audio signal does not contain speech, where the values for K1, K2, K3 and K4 are set as a function of the control signal value; and

an output coupled to the speech processing device, the output operable to output an audio output signal including at least one of the improved speech components of the audio input signal and substantially unaltered non-speech components of the audio input signal;

where the speech processing device further includes a speech improvement device configured to modify the speech component of the received audio input signal; and

the control signal is at least one of configured and controlled to at least one of activate and deactivate the speech improvement device depending on the speech content of the audio signal.