HIGH EFFICIENCY COMPUTER TOMOGRAPHY WITH OPTIMIZED RECURSIONS

• US 20100278413A1
• Filed: 07/16/2010
• Published: 11/04/2010
• Est. Priority Date: 06/27/2008
• Status: Active Grant

• Current Assignee: Wolfram R. Jarisch
• Original Assignee: Wolfram R. Jarisch
• Inventors: Jarisch, Wolfram R.
• Granted Patent: US 8,660,330 B2
• Time in Patent Office: Days
• US Class Current: 382/131
• CPC Class Codes: G06T 11/006 Inverse problem, transformation from projection-space into object-space, e.g. transform methods, back-projection, algebraic methods
• CPC Class Codes: G06T 2211/424 Iterative

Abstract

A system comprising: one or more transmitters to transmit an excitation energy into an object under observation; one or more detectors to generate projection space data encoding an energy received by the one or more detectors in response to the transmitted excitation energy into the object under observation; a controller to control the one or more transmitters to transmit the excitation energy and the one or more receivers to generate the projection space data; and an image reconstructor having at least one processor to receive the projection space data and to process the projection space data by: computing a first quantity characterizing a difference between the projection space data and predicted projection data, wherein the difference between the projection space data and predicted projection data is associated with a projection gain; recording, in a data storage device, a first data encoding the difference; computing a revised first quantity based on recorded first data from preceding iterations; computing an update value using the revised first quantity; and reconstructing an object space image representing the object under observation using the update value.

Claims

1. A system comprising:

one or more transmitters to transmit an excitation energy into an object under observation;

one or more detectors to generate projection space data encoding an energy received by the one or more detectors in response to the transmitted excitation energy into the object under observation;

a controller to control the one or more transmitters to transmit the excitation energy and the one or more receivers to generate the projection space data; and

an image reconstructor having at least one processor to receive the projection space data and to process the projection space data by;

computing a first quantity characterizing a difference between the projection space data and predicted projection data, wherein the difference between the projection space data and predicted projection data is associated with a projection gain;

recording, in a data storage device, a first data encoding said difference;

computing a revised first quantity based on recorded first data from preceding iterations;

computing an update value using the revised first quantity; and

reconstructing an object space image representing the object under observation using the update value.

2. The system according to claim 1, wherein the excitation energy is at least one of electromagnetic (EM) energy, X-Ray energy, particle beams, infra-red energy, optical energy, or vibration energy.

3. The system according to claim 1, wherein said image reconstructor further processes the projection space data by:

recording, in the data storage device, a second data encoding said update value;

revising said update value based on recorded second data from the preceding iterations, wherein the object space image is reconstructed using the revised update value.

4. The system according to claim 1, further comprising:

an output device to receive the object space image representing the object under observation, wherein the output device is at least one of a data storage device, a display device, or a printing device.

5. The system according to claim 1, further comprising:

an investigator computer to receive the object space image and programmed to perform extraction of diagnostic information from the object space image or to fine tune parameters for at least one of the one or more transmitters, the one or more detectors, or the image reconstructor.

6. A workstation comprising:

one or more processors; and

one or more data storage devices storing software to be executed by the one or more processors, the software comprising;

software code to receive input data representing an object projected from an object space to a projection space;

software code to compute a first quantity characterizing a difference between the input data and predicted projection data, wherein the difference between the input data and predicted projection data is associated with a projection gain;

software code to compute an update value using the first quantity;

software code to record, in the one or more data storage devices, or the another one or more data storage devices, a second data encoding said update value;

software code to revise said update value based on recorded second data from the preceding iterations; and

software code to reconstruct an object space image representing the object under observation using the revised update value, wherein the revised update value is associated with a voxel gain.

7. The workstation according to claim 6, wherein the software further comprises:

software code to record, in the one or more data storage devices, or another one or more data storage devices, a first data encoding said difference; and

software code to revise the first quantity based on recorded first data from preceding iterations.

8. The workstation according to claim 6, wherein

said first quantity or said second quantity is stored with a first compression technique, said first data or said second data is stored with a second compression technique, and the second compression technique has a comparable precision compared to the first compression technique.

9. The workstation according to claim 6, wherein the input data is received from at least one of a projection image acquisition system, the one or more data storage devices, another one or more data storage devices, a software simulation executed by the one or more processors, or a software simulation executed by another one or more processors.

10. The workstation according to claim 6, wherein the input data is received via a data bus, a cable, a wired network, or a wireless network.

11. A method implemented by one or more processors executing software code stored on one or more data storage devices, the method comprising:

receiving input data representing an object projected from an object space to a projection space from at least one of a projection image acquisition system, the one or more data storage devices, another one or more data storage devices, a software simulation executed by the one or more processors, or a software simulation executed by another one or more processors;

computing a first quantity characterizing a difference between the input data on a resolution grid and predicted projection data on the resolution grid, wherein the difference between the input data and predicted projection data is associated with a projection gain;

recording, in the one or more data storage devices, or the another one or more data storage devices, a first data encoding said difference;

computing a revised first quantity based on recorded first data from preceding iterations;

computing an update value using the revised first quantity, wherein the update value is associated with a voxel gain;

recording, in the one or more data storage devices, or the another one or more data storage devices, a second data encoding said update value;

revising the update value based on recorded second data from the preceding iterations;

reconstructing an image representing the object under observation using the revised update value, and

outputting the reconstructed image to an output device, wherein the output device is at least one of the one or more data storage devices, another one or more data storage devices, a display device, or a printing device;

wherein receiving the input data, computing the first quantity, recording the first data, computing the revised first quantity, computing the second quantity, reconstructing the image, and outputting the reconstructed image are performed by the one or more processors according to the software code stored on the one or more data storage devices.

12. The method according to claim 11, wherein

said revised first quantity tends to increase the projection gain when said recorded first data have identical signs consecutively from proceeding iterations;

said revised first quantity tends to decrease the projection gain when said recorded first data have alternating signs consecutively from proceeding iterations;

said revised update value tends to increase the voxel gain when said recorded second data have identical signs consecutively from the preceding iterations, and

said revised update value tends to decrease the voxel gain when said recorded second data have alternating signs consecutively from the preceding iterations.

13. The method according to claim 12, wherein said first quantity or second quantity is stored with a first compression technique and said first data or said second data is stored with a second compression technique, and said second compression technique has a comparable precision compared to said first compression technique.

14. The method according to claim 13, further comprising:

smoothing, based on a spatial model, for said update value, said first quantity, or said revised first quantity, wherein said spatial model incorporates at least one of the predicted projection data, the reconstructed image representing the object, or information encoding noise levels or margins of the projection space or the object space.

15. The method according to claim 11, further comprising:

computing a second quantity corresponding to at least one impulse response, each impulse response corresponding to a reference voxel of unit-intensity at a location in the object space, wherein said computing an update value further comprises using an inverted function of the second quantity.

16. The method according to claim 15, wherein the inverted function is computed for a surrounding area covering the location of the reference voxel of unit-intensity in the object space.

17. The method according to claim 15, wherein reconstructing the image comprises:

convolving the first quantity with the inverted function of the second quantity to obtain the update value.

18. The method according to claim 11, wherein the update value is computed using a tomographic reconstruction algorithm.

19. The method according to claim 11, further comprising:

revising the set of object space voxels using the update value.

20. The method according to claim 19, further comprising:

changing to a different resolution grid having a larger size than the resolution grid after the set of object space voxels is revised.