Space-time microwave imaging for cancer detection
First Claim
1. A space-time microwave imaging system for imaging an object comprising:
- (a) an array of antennas for radiating and receiving microwaves;
(b) a microwave pulse source connected to the array of antennas to provide pulse signals to the antennas;
(c) a receiver connected to the antennas to detect the microwave signals received by the antennas and provide signal data corresponding thereto; and
(d) a computer connected to receive the signal data, the computer programmed to estimate an artifact reflection component of the signal at each antenna as a filtered combination of the signals at all other antennas and to subtract the estimated artifact reflection component from the signal data to provide corrected signal data, with weights of the filters chosen to minimize the residual signal over that portion of the received data dominated by the reflection, and the computer further programmed to process the corrected signal data in a beamformer process to time shift the corrected signal data to approximately align the returns from a scatterer at a candidate location, to pass the time aligned signals through a bank of filters with a filter for each antenna, to sum the outputs of the filters to form a summed signal, and to calculate the power in the summed signal to produce a beamformer output signal, wherein the beamformer filters are designed to present maximum gain to scattered signals originating from the candidate location, and to scan the beamformer process to a plurality of different candidate locations in the object to be imaged by changing the time shifts and filter weights to generate multi-dimensional output power data.
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Accused Products
Abstract
Microwave imaging via space-time beamforming is carried out by transmitting microwave signals from multiple antenna locations into an individual to be examined and receiving the backscattered microwave signals at multiple antenna locations to provide received signals from the antennas. The received signals are processed in a computer to remove the skin interface reflection component of the signal at each antenna to provide corrected signal data. The corrected signal data is provided to a beamformer process that time shifts the received signals to align the returns from a scatterer at a candidate location, and then passes the time aligned signals through a bank of filters, the outputs of which are summed, time-gated and the power therein calculated to produce the beamformer output signal at a candidate location. The beamformer is then scanned to a plurality of different locations in the individual by changing the time shifts, filter weights and time-gating of the beamformer process. The output power may be displayed as a function of scan location, with regions of large output power corresponding to significant microwave scatterers such as malignant lesions.
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Citations
46 Claims
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1. A space-time microwave imaging system for imaging an object comprising:
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(a) an array of antennas for radiating and receiving microwaves; (b) a microwave pulse source connected to the array of antennas to provide pulse signals to the antennas; (c) a receiver connected to the antennas to detect the microwave signals received by the antennas and provide signal data corresponding thereto; and (d) a computer connected to receive the signal data, the computer programmed to estimate an artifact reflection component of the signal at each antenna as a filtered combination of the signals at all other antennas and to subtract the estimated artifact reflection component from the signal data to provide corrected signal data, with weights of the filters chosen to minimize the residual signal over that portion of the received data dominated by the reflection, and the computer further programmed to process the corrected signal data in a beamformer process to time shift the corrected signal data to approximately align the returns from a scatterer at a candidate location, to pass the time aligned signals through a bank of filters with a filter for each antenna, to sum the outputs of the filters to form a summed signal, and to calculate the power in the summed signal to produce a beamformer output signal, wherein the beamformer filters are designed to present maximum gain to scattered signals originating from the candidate location, and to scan the beamformer process to a plurality of different candidate locations in the object to be imaged by changing the time shifts and filter weights to generate multi-dimensional output power data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of carrying out space-time microwave imaging of an individual comprising:
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(a) transmitting microwave signals from a plurality of antenna locations into an individual to be examined; (b) receiving backscattered microwave signals at a plurality of antenna locations to provide received signals from the plurality of antenna locations; (c) processing the received signals in a computer in a beamformer process by time shifting the received signal data to approximately align the returns from a scatterer at a candidate location, passing the time aligned signals through a bank of filters with a filter for each antenna location, summing the outputs of the filters to provide a summed signal, and equalizing the summed signal to reduce a sensitivity to a time-gate duration; and
time-gating the equalized signal to provide a time-gated signal, and calculating the power in the time-gated signal to produce a beamformer output signal, wherein the filters are designed to present maximum gain to scattered signals originating from the candidate location; and(d) then scanning the beamformer process to a plurality of different candidate locations in the individual and repeating steps (a), (b) and (c) at each candidate location by changing the time shifts, filter weights and time gates for each candidate location to generate multi-dimensional output power data. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method of compensating for an artifact reflection in microwave imaging of an individual comprising:
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(a) transmitting microwave signals from a plurality of antenna locations into an individual to be examined; (b) receiving backscattered microwave signals at a plurality of antenna locations to provide received signals from the plurality of antenna locations; (c) carrying out an artifact response subtraction process on the received signals in a computer by estimating the artifact reflection component of the signal at each antenna location as a combination of the received signals at the other antenna locations passed through filters to provide corrected signal data, the filters having weights chosen to minimize the received signal over that portion of the received signal dominated by the artifact response; and (d) compensating the corrected signal data for frequency dependent scattering. - View Dependent Claims (28, 29, 30)
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31. A method of carrying out space-time microwave imaging of an individual comprising:
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(a) transmitting microwave signals from a plurality of antenna locations into an individual to be examined; (b) receiving backscattered microwave signals at a plurality of antenna locations to provide received signals from the plurality of antenna locations; (c) carrying out an artifact response subtraction process on the received signals in the computer by estimating the artifact reflection component of the signal at each antenna location as a combination of the received signals at the other antenna locations passed through filters to provide corrected signal data, the filter weights chosen to minimize the received signal over that portion of the received signal dominated by the artifact response; (d) processing the corrected signal data in a computer in a beamformer process by time shifting the received signal data to approximately align the returns from a scatterer at a candidate location, passing the time aligned signals through a bank of filters with one filter in each channel, summing the outputs of the filters to provide a summed signal, and time-gating the summed signal to provide a time-gated signal, and calculating the power in the time-gated signal to produce a beamformer output signal, wherein the filters are designed to present maximum gain to scattered signals originating from the candidate location; and (e) then scanning the beamformer process to a plurality of different candidate locations in the individual and repeating steps (a), (b) (c) and (d) at each candidate location by changing the time shifts, filter weights and time gates for each candidate location to generate multi-dimensional output power data. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. An artifact reflection compensation system for use in space-time microwave imaging comprising:
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(a) an array of antennas for radiating and receiving microwaves; (b) a microwave pulse source connected to the array of antennas to provide pulse signals to the antennas; (c) a receiver connected to the antennas to detect the microwave signals received by the antennas and provide signal data corresponding thereto; and (d) a computer connected to receive the signal data, the computer programmed to estimate an artifact reflection component of the signal at each antenna as a filtered combination of the signals at all other antennas, to subtract the estimated artifact reflection component from the signal data to provide corrected signal data, and to compensate the corrected signal data for frequency dependent scattering. - View Dependent Claims (46)
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Specification