SECURITY SYSTEM AND METHOD USING MEASUREMENT OF ACOUSTIC FIELD VARIATION

• US 20110141283A1
• Filed: 09/09/2010
• Published: 06/16/2011
• Est. Priority Date: 12/14/2009
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Lee, Hong Yeol, LEE, Sung Q, Park, Kang Ho, Kim, Hye Jin, Kim, Jong Dae
• Granted Patent: US 8,797,407 B2
• Time in Patent Office: Days
• US Class Current: 348/152
• CPC Class Codes: G01S 15/526 by comparing echos in different sonar periods
• CPC Class Codes: G01S 15/88 Sonar systems specially adapted for specific applications seismic or acoustic prospecting or detecting G01V1/00
• CPC Class Codes: G08B 13/1609 using active vibration detection systems
• CPC Class Codes: G08B 13/19695 Arrangements wherein non-video detectors start video recording or forwarding but do not generate an alarm themselves

Abstract

A security system and a method of determining whether there is an intrusion are provided. A correlation between sound signals obtained from a sound source generating device and a sound-field variation measuring device is used to measure a acoustic field in a certain space. A difference between an initially set acoustic field and a changed acoustic field is used to determine whether there is an intruding object in a certain space. The security system includes a sound source generating device for generating a sound source; and a sound-field variation measuring device for measuring a acoustic field formed by the sound source, wherein an initially set acoustic field is compared with the measured acoustic field to determine whether there is an intrusion.

Claims

1. A security system using measurement of acoustic field variation, the security system comprising:

a sound source generating device for generating a sound source; and

a sound-field variation measuring device for measuring a acoustic field formed by the sound source inside a certain space, and comparing the measured acoustic field with an initially set acoustic field when the sound source is generated, to determine whether there is an intrusion in the certain space.

2. The security system of claim 1, wherein the sound-field variation measuring device comprises at least one acoustic sensor, and

the acoustic field is obtained by obtaining a sound pressure ratio and a phase difference between the sound source and a measurement position of the acoustic sensor through the acoustic sensor and monitoring a acoustic field between the sound source and a measurement position.

3. The security system of claim 2, wherein the acoustic sensor is a microphone for measuring a signal in a sound wave area generated from the sound source, and

the sound-field variation measuring device further comprises a frequency conversion filter for converting a signal measured by the acoustic sensor into a signal in a frequency domain.

4. The security system of claim 1, wherein the comparison of the initially set acoustic field with the measured acoustic field is performed by comparing transfer functions of the acoustic field to the sound source.

5. The security system of claim 4, wherein the transfer function of the acoustic field is intermittently or continuously measured in a monitoring state.

6. The security system of claim 1, wherein a fuzzy learning scheme or a neural network learning scheme is used to set the initial acoustic field.

7. The security system of claim 1, wherein the sound source includes a pink noise, a white noise or a sine wave in a certain frequency band.

8. The security system of claim 1, wherein the sound-field variation measuring device is synchronized to a sound source from the sound source generating device.

9. The security system of claim 1, further comprising a camera operating when it is determined that there is an intrusion through a comparison of the initially set acoustic field with the measured acoustic field.

10. The security system of claim 9, wherein the camera is a visible light camera or an infrared camera.

11. The security system of claim 10, wherein the camera additionally determines whether there is an intrusion through image signal processing.

12. A security method using measurement of acoustic field variation, the security method comprising;

generating a sound source;

measuring a acoustic field formed by the sound source inside a certain space;

setting an initial transfer function of the acoustic field to the sound source;

intermittently or continuously measuring the acoustic field formed by the sound source to detect a transfer function; and

comparing the initial transfer function with the detected transfer function to determine whether there is an intrusion inside the certain space.

13. The security method of claim 12, further comprising operating a monitoring camera when it is determined that there is an intrusion.

14. The security method of claim 13, wherein the operating of the monitoring camera comprises additionally determining whether there is an intrusion through image signal processing.