System and method for preparing an image corrected for the presence of a gravity induced distortion

• US 7,277,594 B2
• Filed: 11/05/2001
• Issued: 10/02/2007
• Est. Priority Date: 05/03/1999
• Status: Expired due to Fees

• Current Assignee: AO Technology AG
• Original Assignee: AO Technology AG
• Inventors: Guggenheim, Nicolas, Hofstetter, Robert, Scherrer, José L.
• Primary Examiner(s): Bella; Matthew C.
• Assistant Examiner(s): TUCKER, WESLEY J
• Application Number:
  US09/985,585
• Publication Number:
  US 20020109705A1
• Time in Patent Office: 2,157 Days
• Field of Search: 382/100, 382/254, 382/276, 382/289, 382/293, 382/287, 382/275
• US Class Current: 382/275
• CPC Class Codes: A61B 6/08 Auxiliary means for directing the radiation beam to a particular spot, e.g. using light beams
• CPC Class Codes: A61B 6/4441 the rigid structure being a C-arm or U-arm
• CPC Class Codes: A61B 6/547 involving tracking of position of the device or parts of the device
• CPC Class Codes: A61B 6/583 using calibration phantoms
• CPC Class Codes: G01B 11/16 for measuring the deformation in a solid, e.g. optical strain gauge

Abstract

The present invention relates to an imaging system for obtaining an image correctable for the presence of a gravity induced image error. The imaging system includes an imager to obtain an image of an object and a position measurement device to obtain position data indicative of a gravity-induced deformation of the imager. The position data may include gravity vector data indicative of an orientation of a gravity vector.

Claims

1. An imaging system for obtaining a reduced error image that is correctable for the presence of a gravity induced image error, said imaging system comprising:

an imager to obtain an image of an object, the objected being in a suspended state;

at least two markers displaced from one another by a distance attached to the object;

a position measurement device providing object position data indicative of positions of the markers; and

a computer configured to determine a direction of a gravity vector based on the object position data,

wherein deviation of parallelism between the gravity vector and a sensor-based normal is determined by the position measurement device,

wherein the imager is rotated to eliminate the deviation of parallelism between the gravity vector and a sensor-based normal of a sensor-based coordinate system, and

wherein the reduced error image of the objected is taken by the imager.

2. An imaging system according to claim 1, wherein the imager includes multiple optical axes intersecting at a point to define a plane.

3. An imaging system according to claim 2, wherein the sensor-based normal is perpendicular to the plane.

4. An imaging system according to claim 1, wherein the markers are energy emitting markers having a known spatial relationship with respect to the imager.

5. An imaging system according to claim 1, wherein the position measurement device comprises receivers to determine the positions of the markers.

6. An imaging system according to claim 1, wherein the object is suspended by a wire.

7. An imaging system according to claim 3, wherein an x-axis of a gravity-based three-dimensional coordinate system is aligned parallel with a horizontal axis of the imager.

8. An imaging system according to claim 7, wherein an x-axis of a sensor-based three dimensional coordinate system is parallel to the plane.

9. An imaging system according to claim 8, wherein the deviation of parallelism between the gravity vector and the sensor-based normal is based on an angular deviation of the sensor-based coordinate system relative to the gravity-based coordinate system.

10. An imaging system according to claim 9, wherein the reduced error image is obtained by rotation of the sensor-based coordinate system relative to the gravity-based coordinate system as determined by the computer processing signals corresponding to the deviation of parallelism detected by the position measurement device.

11. An imaging system according to claim 1, wherein the imager is an x-ray apparatus and the image is an x-ray image of an animal.

12. A method imaging system for obtaining a reduced error image that is correctable for the presence of a gravity induced image error, said method comprising the steps of:

attaching at least two markers displaced from one another by a distance onto an object to be imaged by an imager;

suspending the objected such that the object is movable;

obtaining object position data indicative of positions of the markers by a position measurement device;

determining a direction of a gravity vector based on the object position data;

determining a deviation of parallelism between the gravity vector and a sensor-based normal of a sensor-based coordinate system;

rotating the imager to eliminate the deviation of parallelism between the gravity vector and a sensor-based normal of a sensor-based coordinate system; and

taking the reduced error image of the objected by the imager.

13. A method according to claim 12, wherein the imager includes multiple optical axes intersecting at a point to define a plane.

14. A method according to claim 13, wherein the sensor-based normal is perpendicular to the plane.

15. A method according to claim 12, wherein the markers are energy emitting markers having a known spatial relationship with respect to the imager.

16. A method according to claim 12, wherein the position measurement device comprises receivers to determine the positions of the markers.

17. A method according to claim 12, wherein the object is suspended by a wire.

18. A method according to claim 14, wherein an x-axis of a gravity-based three-dimensional coordinate system is aligned parallel with a horizontal axis of the imager.

19. A method according to claim 18, wherein an x-axis of the sensor-based three dimensional coordinate system is parallel to the plane.

20. A method according to claim 19, wherein the deviation of parallelism between the gravity vector and the sensor-based normal is based on an angular deviation of the sensor-based coordinate system relative to the gravity-based coordinate system.

21. A method according to claim 20, wherein a reduced error image is obtained by rotation of the sensor-based coordinate system relative to the gravity-based coordinate system as determined by the computer processing signals corresponding to the deviation of parallelism detected by the position measurement device.

22. A method according to claim 12, wherein the imager is an x-ray apparatus and the image is an x-ray image of an animal.