System and a method for detecting the direction of arrival of a sound signal

• US 20060268663A1
• Filed: 05/24/2005
• Published: 11/30/2006
• Est. Priority Date: 05/24/2005
• Status: Active Grant

• Current Assignee: Charly Bitton
• Original Assignee: Charly Bitton
• Inventors: Bitton, Charly
• Granted Patent: US 7,362,654 B2
• Time in Patent Office: Days
• US Class Current: 367/127
• CPC Class Codes: G01S 3/801 Details G01S3/82, G01S3/84, G01S3/86 take precedence
• CPC Class Codes: G01S 3/8083 determining direction of source

Abstract

The disclosed invention is a highly reliable cost effective sound direction detection system. In the preferred embodiment of the invention the system comprises a device which includes two microphones set at a spread of at lease 5 cm from each other, a digital signal processing (DSP) and a command processing board. A pattern recognition algorithm allows the system to recognize the signal of an actual event and distinguish it from echoes and reflections according to several parameters such as the signal'"'"'s time of arrival, energy, amplitude levels and frequency. The pattern of the recorded signals is analyzed according to prevalent signal patterns and then the real event can be identified. By identifying the signal of the sound event and distinguishing it from background noises and from its reflections, the system can calculate its direction of arrival (DOA) using classical sound direction detection methods.

Claims

1. An apparatus for automatically detecting direction of noisy sound events, said apparatus comprised of:

at least two sound detectors positioned in the vicinity of the device;

pattern recognition means for identifying the signal'"'"'s real event;

processing and analyzing means for detecting direction of arrival of sound events in accordance with signal pattern identification.

2. The apparatus of claim 1 wherein the sounds detectors are positioned at a maximum spread within the physical boundaries of the device.

3. The apparatus of claim 1 wherein the detection of sound direction is based on first signal event detection technique.

4. The apparatus of claim 3 wherein the detection of the first signal event is based on a pattern identification criterion of the estimated envelope energy of the sounds signal.

5. The apparatus of claim 1 wherein processing and analyzing means include analyzing the signals'"'"' differential arrival time as sampled by the different microphones.

6. The apparatus of claim 1 further comprising a video camera and means for pointing the video camera means in accordance with the detected direction.

7. A method for automatically detecting the direction of noise events, said method comprising the steps of:

sampling sound signals from at least two different sources in space;

applying pattern recognition techniques for identifying the signal'"'"'s first event;

processing and analyzing all signals for detecting direction of arrival of sound events based on pattern recognition results.

8. The method of claim 7 wherein the signal'"'"'s sample sources detectors are located at a maximum spread in different directions within the physical boundaries of the device.

9. The method of claim 7 wherein sound intensity is determined according to the sampled signal'"'"'s frequency and energy level.

10. The method of claim 7 wherein the detection of direction of arrival is based on first signal event detection technique.

11. The method of claim 7 wherein first signal event detection is based on a is based on a pattern identification criterion of the estimated-envelope energy of the sounds signal.

12. The method of claim 7 wherein the estimation of time of arrival differences between the sound detectors is computed according to frequency properties.

13. The method of claim 7 further comprising the step of turning a surveillance camera in the direction of detected event.