Device and method for integrating sound effect processing and active noise control

• US 20070121956A1
• Filed: 02/28/2006
• Published: 05/31/2007
• Est. Priority Date: 11/29/2005
• Status: Active Grant

• Current Assignee: National Chiao Tung University (Government of The Republic of China)
• Original Assignee: National Chiao Tung University (Government of The Republic of China)
• Inventors: Lin, Jain-Liang, Ou, Kuen-Ying, Bai, Mingsian
• Granted Patent: US 7,889,872 B2
• Time in Patent Office: Days
• US Class Current: 381/59
• CPC Class Codes: G10K 11/17827 Desired external signals, e.g. pass-through audio such as music or speech
• CPC Class Codes: G10K 11/17853 of the filter
• CPC Class Codes: G10K 11/17855 for improving speed or power requirements
• CPC Class Codes: G10K 11/17875 using an error signal without a reference signal, e.g. pure feedback
• CPC Class Codes: G10K 11/17885 additionally using a desired external signal, e.g. pass-through audio such as music or speech
• CPC Class Codes: G10K 2210/1053 Hi-fi, i.e. anything involving music, radios or loudspeakers
• CPC Class Codes: G10K 2210/1081 Earphones, e.g. for telephones, ear protectors or headsets
• CPC Class Codes: H04S 2420/01 Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD]
• CPC Class Codes: H04S 7/30 Control circuits for electronic adaptation of the sound field

Abstract

A device and a method for integrating 3D sound effect processing and active noise control are proposed. A digital signal processor incorporates an artificial reverberator and a 3D spatial audio processor into an audio module. The audio signal is presented via an earphone. Next, a microphone embedded in the vicinity of the loudspeaker inside the headset is used to sense an external noise while playing, and feed it back to an active noise controller, which generates an anti-noise to eliminate the external noise. Therefore, the signal to noise ratio can be increased and the 3D sound field effect can be significantly enhanced. In addition, a head-related transfer function is more efficiently implemented on the basis of an interaural transfer function in the spatial audio processing to reduce the filter order lower and hence the computation loading.

Claims

1. A device for integrating sound effect processing and noise control comprising:

a digital signal processor for performing reverberation and sound positioning processing to an input audio signal;

a sound player comprising a loudspeaker and a sensor disposed in front of said loudspeaker, said sound player receiving and playing said audio signal and using said sensor to detect said audio signal with an external noise attached thereto; and

a noise controller connected to said digital signal processor and said sound player, said noise controller generating an anti-noise signal according to said audio signal with said external noise attached thereto to eliminate interference of said external noise to said audio signal.

2. The device for integrating sound effect processing and noise control as claimed in claim 1, wherein said sound positioning processing includes 3D sound effect processing of a head-related transfer function.

3. The device for integrating sound effect processing and noise control as claimed in claim 2, wherein said head-related transfer function can be expressed by an interaural transfer function.

4. The device for integrating sound effect processing and noise control as claimed in claim 3, wherein said interaural transfer function is the difference value between an ipsi-lateral impulse response at the same side with the sound source and a contra-lateral impulse response at the other side of the sound source.

5. The device for integrating sound effect processing and noise control as claimed in claim 4, wherein using said interaural transfer function to express said head-related transfer function comprises the steps of:

convoluting said audio signal with said ipsi-lateral impulse response to obtain an ipsi-lateral output signal; and

using said interaural transfer function to convert said ipsi-lateral output signal and adding a corresponding interaural time difference to obtain a contra-lateral output signal.

6. The device for integrating sound effect processing and noise control as claimed in claim 4, wherein Wiener filter is used to obtain a realized structure of a lower-order finite impulse response filter of said interaural transfer function.

7. The device for integrating sound effect processing and noise control as claimed in claim 6, wherein said realized structure of said finite impulse response filter is designed for the audible frequency range of human, and ignores sound frequencies that are inaudible.

8. The device for integrating sound effect processing and noise control as claimed in claim 1, wherein said noise controller is based on the quantitative feedback theory (QFT), and is designed for the specification of said sound player.

9. The device for integrating sound effect processing and noise control as claimed in claim 1, wherein said device can apply to earphones and mobile phones.

10. A method for integrating sound effect processing and noise control comprising the steps of:

inputting an audio signal;

performing reverberation and sound positioning processing to said audio signal;

playing said audio signal by a sound player;

using a sensor in said sound player to receive said audio signal and the simultaneous external noise when playing;

transferring said audio signal with said external noise attached thereto to a noise controller;

using said noise controller to generating an anti-noise signal to eliminate interference of said external noise; and

using said sound player to play said audio signal with said external noise already eliminated.

11. The method for integrating sound effect processing and noise control as claimed in claim 10, wherein said sound positioning processing includes 3D sound effect processing of a head-related transfer function.

12. The method for integrating sound effect processing and noise control as claimed in claim 11, wherein said head-related transfer function can be expressed by an interaural transfer function.

13. The method for integrating sound effect processing and noise control as claimed in claim 12, wherein said interaural transfer function is the difference value between an ipsi-lateral impulse response at the same side with the sound source and a contra-lateral impulse response at the other side of the sound source.

14. The method for integrating sound effect processing and noise control as claimed in claim 13, wherein using said interaural transfer function to express said head-related transfer function comprises the steps of:

convoluting said audio signal with said ipsi-lateral impulse response to obtain a ipsi-lateral output signal; and

using said interaural transfer function to convert said ipsi-lateral output signal and adding a corresponding interaural time difference to obtain a contra-lateral output signal.

15. The method for integrating sound effect processing and noise control as claimed in claim 13, wherein Wiener filter is used to obtain a realized structure of a lower-order finite impulse response filter of said interaural transfer function.

16. The method for integrating sound effect processing and noise control as claimed in claim 15, wherein said realized structure of said finite impulse response filter is designed for the audible frequency range of human, and ignores sound frequencies that are inaudible.