System and method for boundary estimation using CT metrology
First Claim
Patent Images
1. A method for computed tomography (CT) reconstruction, the method comprising:
- initializing a boundary of an object to obtain a boundary estimate;
defining a forward model based on the boundary estimate;
linearizing the forward model to obtain a system matrix; and
implementing an iterative image reconstruction process using the system matrix to update the boundary estimate.
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Abstract
A technique is provided for CT reconstruction for use in CT metrology. The boundary based CT reconstruction method includes the steps of initializing a boundary of an object to obtain a boundary estimate, defining a forward model based on the boundary estimate, linearizing the forward model to obtain a system matrix and implementing an iterative image reconstruction process using the system matrix to update the boundary estimate.
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Citations
62 Claims
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1. A method for computed tomography (CT) reconstruction, the method comprising:
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initializing a boundary of an object to obtain a boundary estimate;
defining a forward model based on the boundary estimate;
linearizing the forward model to obtain a system matrix; and
implementing an iterative image reconstruction process using the system matrix to update the boundary estimate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A computed tomography (CT) metrology method, the method comprising:
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generating a boundary estimate of an object from a measured sinogram;
generating a partially calculated sinogram based upon the boundary estimate;
updating a system matrix based upon the boundary estimate;
calculating at least one sinogram perturbation from at least one of the system matrix and a set of boundary perturbations;
adding the partially calculated sinogram and the at least one sinogram perturbation to derive a total calculated sinogram;
updating the set of boundary perturbations based upon at least one of the measured sinogram, the total calculated sinogram, and the system matrix; and
updating the boundary estimate based upon the set of boundary perturbations. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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50. A computed tomography (CT) metrology system comprising:
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a source for emitting radiation;
a controller configured to operate the source;
an array of detector units configured to detect radiation transmitted through the object and to generate a detector output signal in response to the detected radiation;
data acquisition circuitry for acquiring the detector output signal;
an image reconstructor coupled to the data acquisition circuitry for generating an image signal in response to the detector output signal, wherein the image reconstructor is configured to initialize a boundary of an object to obtain a boundary estimate, to define a forward model based on the boundary estimate, to linearize the forward model to obtain a system matrix, and to implement an iterative image reconstruction process using the system matrix to update the boundary estimate; and
a computer for controlling the operation of at least one of the controller, the data acquisition circuitry and the image reconstructor. - View Dependent Claims (51)
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52. A computed tomography (CT) metrology sytem comprising:
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a source for emitting radiation;
a controller configured to operate the source;
an array of detector units configured to detect radiation transmitted through the object and to generate a detector output signal in response to the detected radiation;
data acquisition circuitry for acquiring the detector output signal;
an image reconstructor coupled to the data acquisition circuitry for generating an image signal in response to the detector output signal, wherein the image reconstructor is configured to generate a boundary estimate of an object from a measured sinogram, to update a system matrix based upon the boundary estimate, to generate a partially calculated sinogram based on the boundary estimate, to calculate at least one sinogram perturbation from at least one of the system matrix and a set of boundary perturbations, to add the partially calculated sinogram and the at least one sinogram perturbation to derive a total calculated sinogram, to update the set of boundary perturbations based upon at least one of the measured sinogram, the total calculated sinogram, and the system matrix, and to update the boundary estimate based upon the set of boundary perturbations; and
a computer for controlling the operation of at least one of the controller, the data acquisition circuitry and the image reconstructor. - View Dependent Claims (53, 54, 55, 56)
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57. A, tangible, machine readable media, comprising:
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code adapted to initialize a boundary of an object to obtain a boundary estimate;
code adapted to define a forward model based on the boundary estimate code adapted to linearize the forward model to obtain a system matrix; and
code adapted to implement an iterative image reconstruction process using the system matrix to update the boundary estimate.
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58. A tangible, machine readable media, comprising:
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code adapted to generate a boundary estimate of an object from a measured sinogram;
code adapted to update a system matrix based upon the boundary estimate;
code adapted to generate a partially calculated sinogram based on the boundary estimate;
code adapted to calculate at least one sinogram perturbation from at least one of the system matrix and a set of boundary perturbations;
code adapted to add the partially calculated sinogram and the at least one sinogram perturbation to derive a total calculated sinogram;
code adapted to update the set of boundary perturbations based upon at least one of the measured sinogram, the total calculated sinogram, and the system matrix; and
code adapted to update the boundary estimate based upon the set of boundary perturbations. - View Dependent Claims (59, 60)
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61. A computed tomography (CT) metrology system comprising:
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means for initializing a boundary of an object to obtain a boundary estimate;
means for defining a forward model based on the boundary estimate means for linearizing the forward model to obtain a system matrix; and
means for implementing an iterative image reconstruction process using the system matrix to update the boundary estimate.
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62. A computed tomography (CT) metrology system comprising:
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means for generating a boundary estimate of an object from a measured sinogram;
means for updating a system matrix based upon the boundary estimate;
means for generating a partially calculated sinogram based on the boundary estimate;
means for calculating at least one sinogram perturbation from at least one of the system matrix and a set of boundary perturbations;
means for adding the partially calculated sinogram and the at least one sinogram perturbation to derive a total calculated sinogram;
means for updating the set of boundary perturbations based upon at least one of the measured sinogram, the total calculated sinogram, and the system matrix; and
means for updating the boundary estimate based upon the set of boundary perturbations.
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Specification