Techniques for building-scale electrostatic tomography

• US 20050167588A1
• Filed: 11/22/2004
• Published: 08/04/2005
• Est. Priority Date: 12/30/2003
• Status: Active Grant

• Current Assignee: Mitre Corporation
• Original Assignee: Mitre Corporation
• Inventors: Donnangelo, Nicholas C.
• Granted Patent: US 7,330,032 B2
• Time in Patent Office: Days
• US Class Current: 250/307
• CPC Class Codes: A61B 5/0536 Impedance imaging, e.g. by tomography
• CPC Class Codes: G01N 27/60 by investigating electrostatic variables , e.g. electrographic flaw testing G01N27/007 takes precedence
• CPC Class Codes: G01R 29/14 Measuring field distribution

Abstract

Techniques for imaging a search region to detect a dielectric target include placing multiple electrodes outside the search region. At least two electrodes are activated independently of each other. Emitter circuits are connected to corresponding emitter electrodes. Each emitter circuit is configured for using its emitter electrode to produce an electric field with wavelength longer than about one hundred meters. Receiver circuits are connected to corresponding receiver electrodes. Each receiver circuit is configured for using its receiver electrode to measure a property of an electric field produced, at least in part, by an emitter electrode. A processor determines a property of a dielectric target inside the search region based on measurements from the receiver circuits using a subset of the emitter circuits. Among other uses, these techniques allow humans to be detected inside building-size regions, even when hidden by visually opaque blocking material of small dielectric constant.

Claims

1-27. -27. (canceled)

28. A method, comprising:

(a) positioning a first electrode of a plurality of electrodes with respect to a second electrode of the plurality of electrodes to bound a search region;

(b) producing at least part of an electric field having a predetermined wavelength using an emitter electrode of the plurality of electrodes;

(c) measuring a property of the electric field using a receiver electrode of the plurality of electrodes; and

(d) determining, based at least in part on step (c), a property of a dielectric target in the search region.

29. The method of claim 28, wherein the predetermined wavelength comprises a wavelength longer than about one hundred meters.

30. The method of claim 28, wherein step (a) further comprises positioning all of the electrodes completely inside the search region.

31. The method of claim 28, wherein:

step (b) further comprises producing the electric field at each of a plurality of frequencies; and

step (d) further comprises determining a spectral response for the dielectric target for each of the plurality of frequencies.

32. The method of claim 28, wherein step (d) further comprises determining at least one of:

a dielectric constant of the dielectric target;

a position of the dielectric target within the search region;

a size of the dielectric target;

an elongation of the dielectric target;

an orientation of the dielectric target when it is configured as an elongated dielectric target; and

a spectrally dependent dielectric constant of the dielectric target.

33. The method of claim 28, further comprising:

(e) associating a dielectric constant of the dielectric target with a biological entity.

34. The method of claim 28, wherein step (a) further comprises positioning the plurality of electrodes so that they are separated from the dielectric target using a blocking material having a dielectric constant less than about 10.

35. The method of claim 34, further comprising using a visually opaque material as the blocking material.

36. The method of claim 34, wherein step (a) further comprises positioning the plurality of electrodes so that they are not in contact with the blocking material.

37. The method of claim 34, further comprising embedding one or more electrically conducting structures in the blocking material.

38. The method of claim 28, wherein step (a) further comprises positioning the first electrode to optimize performance of step (d).

39. The method of claim 28, step (a) further comprises positioning the first electrode with respect to the second electrode to optimize performance of step (d).

40. The method of claim 28, wherein step (a) further comprises positioning the first electrode so that is spaced more than about five meters from the second electrode.

41. The method of claim 31, wherein step (d) further comprises:

(e) distinguishing a biological target from a non-biological target based at least in part on the spectral response.

42. The method of claim 28, further comprising:

(e) excluding a particular electrode of the plurality of electrodes from the receiver electrodes during production of a particular electric field by a particular one of the emitter electrodes.

43. The method of claim 42, wherein step (e) performs the excluding to optimize performance of step (d).

44. The method of claim 28, wherein step (b) further comprises producing the electric field using only one of the emitter electrodes at a time.

45. The method of claim 28, wherein step (b) further comprises:

determining a particular temporal sequence for using the plurality of emitter electrodes to optimize step (d); and

producing the electric field using the plurality of emitter electrodes in the particular temporal sequence.

46. The method of claim 28, wherein step (c) further comprises using a particular receiver electrode of the plurality of receiver electrodes that is also an emitter electrode of the plurality of emitter electrodes.

47. The method of claim 28, wherein step (c) further comprises measuring an electrical potential of the electric field at a receiver electrode of the plurality of receiver electrodes.

48. The method of claim 28, wherein step (c) further comprises measuring a current induced by the electric field at a receiver electrode of the plurality of receiver electrodes.

49. The method of claim 28, wherein step (c) further comprises measuring an associated magnetic field at a receiver electrode of the plurality of receiver electrodes.

50. The method of claim 28, wherein step (d) further comprises performing a forward computation that includes representing the dielectric target as an object that allows an analytical solution for the property of the electric field at a receiver electrode of the plurality of receiver electrodes.

51. The method of claim 28, wherein:

step (b) further comprises (b1) producing a first electric field using a first emitter electrode of the plurality of electrodes and (2) producing a second electric field using a second emitter electrode of the plurality of electrodes after producing the first electric field; and

step (a) further comprises positioning the electrode after step (b1) and before step (b2).

52. The method of claim 51, the method further comprising:

(e) determining a position change for the electrode with respect to the different electrode based on measuring the property of the first electric field using a first plurality of receiver electrodes of the plurality of electrodes, wherein step (a) further comprises positioning the electrode according to the position change.

53. The method of claim 52, wherein step (e) further comprises determining the position change to optimize step (d).

54. The method of claim 51, wherein the first emitter electrode is the same as the second emitter electrode.

55. The method of claim 51 wherein the first emitter electrode is different from the second emitter electrode.

56. The method of claim 28, wherein step (b) further comprises emitting one or more temporal pulses of an electric field, each pulse comprising a combination of a plurality of wavelengths, each wavelength longer than about one hundred meters.

57-86. -86. (canceled)