Method and apparatus using acoustic sensor for sub-surface object detection and visualization

• US 6,536,553 B1
• Filed: 04/25/2000
• Issued: 03/25/2003
• Est. Priority Date: 04/25/2000
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Scanlon, Michael V.
• Primary Examiner(s): Lobo, Ian J.
• Application Number:
  US09/557,939
• Time in Patent Office: 1,064 Days
• Field of Search: 736/39, 736/36, 735/94, 367/87, 367/97, 367/178, 181/108, 181/401
• US Class Current: 181/108
• CPC Class Codes: G01N 2291/0421 Longitudinal waves
• CPC Class Codes: G01N 2291/105 two or more emitters, two or more receivers
• CPC Class Codes: G01N 29/069 Defect imaging, localisation and sizing using, e.g. time of flight diffraction [TOFD], synthetic aperture focusing technique [SAFT], Amplituden-Laufzeit-Ortskurven [ALOK] technique
• CPC Class Codes: G01N 29/226 Handheld or portable devices
• CPC Class Codes: G01N 29/2493 Wheel shaped probes
• CPC Class Codes: G01N 29/28 providing acoustic coupling , e.g. water impedance matching G10K11/02
• CPC Class Codes: G01V 1/001 Acoustic presence detection
• CPC Class Codes: G01V 1/047 Arrangements for coupling the generator to the ground
• CPC Class Codes: Y10S 181/401 Earth

Abstract

An apparatus for detecting an underground abject includes a container in contact with the ground surface; a medium disposed in the container; at least one acoustic sensor disposed in the medium in the container; and an output device connected to the acoustic sensor. A portion of the container in contact with the ground is substantially acoustically transparent and conforms to contours of the ground. The acoustic impedance of the medium in the container is substantially the same as the acoustic impedance of the ground. A method of detecting an underground object includes receiveing reflected acoustic noise with at least one acoustic sensor immersed in a medium, the mediukm being desposed in a container in contact with a ground surface; converting the reflected acoustic noise to electrical signals; and, using an output device, converting teh eletrical signals to a form that can be sensed by a human to determine if the undergroung object has been detected.

Claims

1. An apparatus for detecting an underground object, comprising:

a roller container having a generally cylindrical shape being in contact with a ground surface, wherein at least a portion of said roller container that contacts the ground is substantially acoustically transparent and made of a substantially flexible material of one of rubber, polyethylene, polyvinylchloride, vinyl and a plastic material, such that the portion of the roller container that contacts the ground surface substantially conforms to a contour of the ground surface;

a medium of at least one liquid and one gel disposed in the roller container;

a shaft that passes through the roller container;

a plurality of acoustic sensors for detecting acoustic noise disposed in the medium in the roller container and arranged in triads so that at least one of the acoustic sensors is mounted on the shaft;

a plurality of acoustic sources that emit acoustic noise symmetrically located at a midpoint of each sensor triad such that at least one of the acoustic sources is mounted on the shaft; and

an output device connected to the plurality of acoustic sensors.

14. The apparatus of claim 1, further comprising a plurality of roller containers, the plurality of roller containers comprising two end roller container and at least one interior roller container a transverse member;

two end arms connected at one end to an end roller container and at the other end rigidly connected to the transverse member;

at least one rocker arm connected at one end to the at least one interior roller containers and at the other end rotatably connected to the transverse member; and

a handle connected to the transverse member.

15. The apparatus of claim 1, further comprising a global positioning system attached to the apparatus.

2. An apparatus for detecting an underground object, comprising:

a roller container having a generally cylindrical shape being in contact with a ground surface, wherein at least a portion of said roller container that contacts the ground is substantially acoustically transparent and made of a substantially flexible material of one of rubber, polyethylene, polyvinylchloride, vinyl and a plastic material, such that the portion of the roller container that contacts the ground surface substantially conforms to a contour of the ground surface;

a medium of at least one liquid and one gel disposed in the roller container;

a shaft that passes through the roller container;

a handle attached to the shaft for moving the roller across the ground surface;

a rear wheel assembly attached to the handle, for decreasing loading of the roller on the ground surface;

at least one acoustic sensor disposed in the medium in the roller container, for detecting acoustic noise roller wherein the at least one acoustic sensor is mounted on the shaft;

at least one acoustic source that emits acoustic noise wherein the at least one acoustic source is mounted on the shaft; and

an output device connected to the plurality of acoustic sensors.

3. An apparatus for detecting an underground object, comprising:

a roller container having a generally cylindrical shape being in contact with a ground surface, wherein at least a portion of said roller container that contacts the ground is substantially acoustically transparent and made of a substantially flexible material of one of rubber, polyethylene, polyvinylchloride, vinyl and a plastic material, such that the portion of the roller container that contacts the ground surface substantially conforms to a contour of the ground surface;

a medium of at least one liquid and one gel disposed in the roller container;

a shaft that passes through the roller container;

at least one acoustic sensor disposed in the medium in the roller container, for detecting acoustic noise roller wherein the at least one acoustic sensor is mounted on the shaft;

at least one acoustic sensor disposed outside of the roller;

a frame attached to the shaft of the roller for supporting the at least one acoustic sensor disposed outside of the roller; and

an output device connected to the acoustic sensor.

4. An apparatus for detecting an underground object, comprising:

a roller container having a generally cylindrical shape being in contact with a ground surface, wherein at least a portion of said roller container that contacts the ground is substantially acoustically transparent and made of a substantially flexible material of one of rubber, polyethylene, polyvinylchloride, vinyl and a plastic material, such that the portion of the roller container that contacts the ground surface substantially conforms to a contour of the ground surface;

a medium of at least one liquid and one gel disposed in the roller container;

a shaft that passes through the roller container;

at least one acoustic sensor disposed in the medium in the roller container, for detecting acoustic noise roller wherein the at least one acoustic sensor is mounted on the shaft;

a second roller container located in front of the roller container and a frame attached to the shaft of the roller container for supporting the second roller; and

an output device connected to the acoustic sensor.

5. An apparatus for detecting an underground object, comprising:

a roller container having a generally cylindrical shape being in contact with a ground surface, wherein at least a portion of said roller container that contacts the ground is substantially acoustically transparent and made of a substantially flexible material of one of rubber, polyethylene, polyvinylchloride, vinyl and a plastic material, such that the portion of the roller container that contacts the ground surface substantially conforms to a contour of the ground surface;

a medium of at least one liquid and one gel disposed in the roller container;

a shaft that passes through the roller container;

at least one acoustic sensor disposed in the medium in the roller container, for detecting acoustic noise roller wherein the at least one acoustic sensor is mounted on the shaft;

a collection chamber assembly mounted on the shaft inside the roller container at one end thereof, the collection chamber assembly comprising a chamber with openings formed therein for collecting and releasing higher density medium; and

an output device connected an output device connected to the acoustic sensor.

6. The apparatus of claim 5, wherein the collection chamber assembly further comprises an open/close plate with openings formed therein for selectively opening and closing the openings formed in the chamber.

7. An apparatus for detecting an underground object, comprising:

a roller container having a generally cylindrical shape being in contact with a ground surface, wherein at least a portion of said roller container that contacts the ground is substantially acoustically transparent and made of a substantially flexible material of one of rubber, polyethylene, polyvinylchloride, vinyl and a plastic material, such that the portion of the roller container that contacts the ground surface substantially conforms to a contour of the ground surface;

a medium of at least one liquid and one gel disposed in the roller container;

at least one acoustic sensor disposed in the medium in the roller container, for detecting acoustic noise roller;

at least one acoustic source that emits acoustic noise;

a shaft that passes through the roller container wherein the shaft includes a bearing portion and a shroud portion, the at least one acoustic sensor and the at least one acoustic source being mounted on the shroud portion; and

an output device connected to the acoustic sensor.

8. The apparatus of claim 7, further comprising an acoustic absorber mounted on a top of the shroud portion.

9. An apparatus for detecting an underground object, comprising:

a container having a rigid top plate, said container being in contact with a ground surface wherein at least a portion of said container is substantially acoustically transparent;

a medium of at least one liquid and one gel disposed in the container;

at least one acoustic sensor for detecting acoustic noise mounted on the bottom of the rigid top plate and disposed in the medium in the container; and

an output device connected to the acoustic sensor.

10. The apparatus of claim 9, further comprising a plurality of acoustic sensors mounted on the bottom of the rigid top plate.

11. The apparatus of claim 10, further comprising a handle attached to the rigid top plate.

12. The apparatus of claim 10, further comprising a plurality of preamplifiers connected to the plurality of acoustic sensors, respectively, at least one of a plurality of filters, a plurality of means for modifying a signal and a plurality of means for processing a signal connected to the plurality of preamplifiers, respectively, and a plurality of visual indicators connected to the plurality of filters respectively.

13. The apparatus of claim 12, wherein the plurality of preamplifiers and the at least one of a plurality of filters, a plurality of means for modifying a signal and a plurality of means for processing a signal are disposed in an interior of the rigid top plate and the plurality of visual indicators are mounted on a top of the rigid top plate.

16. A method of detecting an underground object, comprising:

emitting acoustic noise toward the underground object using at least one acoustic source and receiving the acoustic noise from the underground object with at least one acoustic sensor immersed in a medium, the medium being disposed in a container in contact with a ground surface;

focusing the emitted acoustic noise using one of a shroud and a baffle.

converting the received acoustic noise to electrical signals; and

using an output device, converting the electrical signals to a form that can be sensed by a human to determine if the underground object has been detected.

17. A method of detecting an underground object, comprising:

receiving at least one of acoustic noise emanating from and acoustic noise reflected from the underground object with at least one acoustic sensor immersed in a medium, the medium being disposed in a container in contact with a ground surface;

imparting directional sensitivity to the at least one acoustic sensor using one of a shroud and a baffle.

converting the received acoustic noise to electrical signals;

using an output device, converting the electrical signals to a form that can be sensed by a human to determine if the underground object has been detected.

18. An apparatus for detecting an underground object, comprising:

a plurality of the following device;

a container in contact with a ground surface, wherein at least a portion of the container that contacts the ground surface is substantially acoustically transparent, and wherein the container comprises a rigid top plate;

a medium disposed in the container, wherein the medium is at least one of liquid and gel;

at least one acoustic sensor disposed in the medium in the container, for detecting acoustic noise, the at least one acoustic sensor comprising a single acoustic sensor mounted on a bottom of the rigid top plate;

an output device connected to the acoustic sensor;

a frame; and

a plurality of elastic members for connecting the plurality of said devices to said frame and to each other.

19. The apparatus of claim 18, wherein the plurality of said devices comprise a linear array.

20. The apparatus of claim 18, wherein the plurality of said devices comprise a planar array.

21. The apparatus of claim 18, wherein at least one of the plurality of said devices includes an acoustic source.