Patent US4805627A successfully refreshed from Google Patents.
US4805627A
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Method and apparatus for identifying the distribution of the dielectric constants in an object
Assignee: Siemens AG
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Filing: 1986-09-04
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Granted: 1989-02-21
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Expires: 2006-09-04
Abstract
Abstract A method and apparatus for identifying the distribution of the dielectric constants in an object employ radiation emitted by a microwave transmitter directed at the object, which radiation is received by a microwave detector array. The dielectric constant distribution is calculated in a computer from the output signal of the detector array, and is represented on a monitor. The transmitted and scattered radiation is acquired by the array in a prescribed volume in terms of amplitude and phase. For this purpose, the array has a surface with detector elements thereon which is linearly displaceable in a direction toward the microwave transmitter in steps along a selected path. At each step, the incoming radiation is identified in terms of amplitude and phase at a plurality of measuring locations, the number of measuring locations corresponding to the number of individual detector elements within the array. This measuring phase is thereafter combined with a calibration phase for further processing.
Inventors
- 👤 Klaus Klingenbeck
- 👤 Judith Regn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:57
CPC Classifications
G; G01; G01N; G01N22/00
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
161 words
A method for identifying the distribution of dielectric constants in an object in a scan of said object comprising the steps of: during said scan, emitting radiation directed at said object thereby causing said object to multiply scatter and transmit radiation attenuated by said object forming a three-dimensional attenuated and scattered radiation field; defining a selected volume outside said object in said attenuated and scattered radiation field; receiving said attenuated and scattered radiation within said selected volume; measuring at each of a plurality of selected locations within said volume the received radiation in terms of amplitude and phase to obtain a data set for said scan; calculating a three-dimensional distribution of the dielectric constants in said object from the amplitudes and phases of the radiation received within said selected volume in said data set based at least in part on the multiple scattering of said radiation within said object; selecting a section of said three-dimensional distribution; and visually displaying said section.
Claim 2
Independent Claim
161 words
A method for identifying the distribution of dielectric constants in an object in a scan of said object comprising the steps of: during said scan, emitting radiation directed at said object thereby causing said object to multiply scatter and transmit radiation attenuated by said object forming a three-dimensional attenuated and scattered radiation field; defining a selected volume outside said object in said attenuated and scattered radiation field; receiving said attenuated and scattered radiation within said selected volume; measuring at each of a plurality of selected locations within said volume the received radiation in terms of amplitude and phase to obtain a data set for said scan; calculating a three-dimensional distribution of the dielectric constants in said object from the amplitudes and phases of the radiation received within said selected volume in said data set based at least in part on the multiple scattering of said radiation within said object; selecting a section of said three-dimensional distribution; and visually displaying said section.
Claim 3
Dependent Claim
24 words
A method as claimed in claim 1, wherein the step of emitting radiation is further defined by emitting microwave radiation directed at said object.
Claim 4
Dependent Claim
24 words
A method as claimed in claim 1, wherein the step of emitting radiation is further defined by emitting ultrasonic radiation directed at said object.
Claim 5
Dependent Claim
45 words
A method as claimed in claim 1, wherein said radiation is received by a two-dimensional detector array, and comprising the additional step of linearly displacing said detector array in a direction toward and away from said object to receive said radiation within said selected volume.
Claim 6
Dependent Claim
18 words
A method as claimed in claim 4, comprising the additional step of rotating said array around said object.
Claim 7
Dependent Claim
64 words
A method as claimed in claim 1, comprising the additional steps of: undertaking a calibration measurement in the absence of said object with a radiation detector disposed at a position to be subsequently occupied by said object; storing the measurements of phase and amplitude of said radiation in a memory from said calibration step; and using the stored calibration measurements in said calculating step.
Claim 8
Dependent Claim
171 words
A method as claimed in claim 1, wherein the step of calculating a three-dimensional distribution of the dielectric constants is further defined by calculating said distribution using the following equations: ##EQU2## wherein V(r) is the scattering potential, ω=2π f is the angular frequency of the emitted radiation, c is the speed of light, ε is the dielectric constant of the radiation coupling medium surrounding said object, μ is the permeability of said coupling medium, μ(r) is the permeability of said object, G S is the Green's function describing the propagation of the radiation from said object to a measuring location within said selected volume, G T is the Green's function describing the propagation of radiation between two locations in said object, G S -1 is the inverted Green's function G S , ψ o is the incoming radiation field at the location of the object, ψ S is the scattered field at said measuring location, is a unit operator, and ε(r) is said distribution of the dielectric constants in said object.
Claim 9
Dependent Claim
38 words
A method as claimed in claim 7, wherein the step of calculating is undertaken in a matrix format using fast Fourier transform techniques applied to the scattered field within said selected volume, and wherein is the unit matrix.
Claim 10
Dependent Claim
33 words
A method as claimed in claim 1, wherein said radiation is received by a one-dimensional detector, and comprising the additional steps of: linearly displacing said detector; and rotating said detector around said object.
Claim 11
Independent Claim
173 words
An apparatus for identifying the distribution of dielectric constants in an object in a scan of said object comprising: means for emitting radiation directed at said object during said scan thereby causing said object to multiply scatter and transmit radiation attenuated by said object forming a three-dimensional attenuated and scattered radiation field; means for defining a selected volume outside of said object in said attenuated and scattered radiation field; means for receiving said attenuated and scattered radiation within said selected volume; means for measuring at each of a plurality of selected locations within said volume the received radiation in terms of amplitude and phase to obtain a data set for said scan; means for calculating a three-dimensional distribution of the dielectric constants in said object from the amplitudes and phases of the radiation received within said selected volume in said data set based at least in part on the multiple scattering of said radiation within said object; means for selecting a section of said three-dimensional distribution; and means for visually displaying said section.
Claim 12
Independent Claim
173 words
An apparatus for identifying the distribution of dielectric constants in an object in a scan of said object comprising: means for emitting radiation directed at said object during said scan thereby causing said object to multiply scatter and transmit radiation attenuated by said object forming a three-dimensional attenuated and scattered radiation field; means for defining a selected volume outside of said object in said attenuated and scattered radiation field; means for receiving said attenuated and scattered radiation within said selected volume; means for measuring at each of a plurality of selected locations within said volume the received radiation in terms of amplitude and phase to obtain a data set for said scan; means for calculating a three-dimensional distribution of the dielectric constants in said object from the amplitudes and phases of the radiation received within said selected volume in said data set based at least in part on the multiple scattering of said radiation within said object; means for selecting a section of said three-dimensional distribution; and means for visually displaying said section.
Claim 13
Dependent Claim
16 words
An apparatus as claimed in claim 10, wherein said means for emitting is a microwave transmitter.
Claim 14
Dependent Claim
16 words
An apparatus as claimed in claim 10, wherein said means for emitting is an ultrasonic transmitter.
Claim 15
Dependent Claim
24 words
An apparatus as claimed in claim 10, wherein said means for receiving radiation is a detector array having a plurality of individual detector elements.
Claim 16
Dependent Claim
21 words
An apparatus as claimed in claim 13, wherein said individual detector elements of said array are disposed on a flat surface.
Claim 17
Dependent Claim
15 words
An apparatus as claimed in claim 13, wherein said individual detector elements are dipole antennas.
Claim 18
Dependent Claim
39 words
An apparatus as claimed in claim 10, wherein said means for receiving radiation is a two-dimensional detector array, further comprising: means for moving said means for receiving radiation linearly toward and away from said object through said selected volume.
Claim 19
Dependent Claim
20 words
An apparatus as claimed in claim 10, further comprising means for rotating said means for receiving radiation around said object.
Claim 20
Dependent Claim
41 words
An apparatus as claimed in claim 10, further comprising a container in which said means for emitting radiation, said means for receiving radiation, and said object are disposed, said container being filled with a coupling medium having a high dielectric constant.
Claim 21
Dependent Claim
65 words
An apparatus as claimed in claim 10, wherein said means for emitting radiation includes an RF oscillator and wherein said means for measuring the received radiation includes a phase sensitive detector, and wherein said phase sensitive detector has an input connected to an output of said RF oscillator for supplying the output of the RF oscillator to the phase sensitive detector as a reference signal.
Claim 22
Dependent Claim
38 words
An apparatus as claimed in claim 19, further comprising an analog-to-digital converter connected to an output of said phase sensitive detector, and a means for storing data having an input connected to the output of said analog-to-digital converter.
Claim 23
Dependent Claim
75 words
An apparatus as claimed in claim 20, wherein said means for storing said data comprises a first memory for storing calibration data taken in the absence of said object with said means for receiving radiation disposed at a position subsequently to be occupied by said object, and a second memory for storing measured data from said object, and means for switching the output of said analog-to-digital converter to one of said first or second memories.
Claim 24
Dependent Claim
40 words
An apparatus as claimed in claim 21, wherein said means for calculating is a computer having inputs respectively connected to outputs of said first and second memories, and having an output connected to said means for visually displaying said section.
Claim 25
Dependent Claim
25 words
An apparatus as claimed in claim 22, further comprising a control line from said computer to said means for emitting radiation for controlling operation thereof.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-21 | 1992-08-22 | 1993-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-21 | 1996-08-22 | 1997-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-21 | 2000-08-22 | 2001-02-21 | $7700.00 | Window Closed / Lapsed |