System and method for replacing a rotational axis decoder in a scanning system
A method for determining the position and/or orientation of at least one sensor system relative to the base structure of a scanning system during scanning of an object includes obtaining one or more tracking images using one or more cameras, where the cameras are in a fixed position with respect to the sensor system; and determining from the one or more tracking images the position and/or orientation of the sensor system relative to the base structure at a given time.
1. A method for determining the position or orientation of at least one sensor system relative to the base structure of a cone beam computed tomography scanning system during scanning of an object, the method comprising:
obtaining one or more tracking images using one or more cameras, where the cameras are in a fixed position with respect to the sensor system; and
determining from the one or more tracking images the position or orientation of the sensor system relative to the base structure at a given time;
wherein:
a tracking element is attached in a fixed position with respect to the base structure of the scanning system, the tracking element comprising one or more fiducial markers in a known configuration;
the tracking images are images taken of the tracking element;
the tracking images are processed to identify the position of the one or more fiducial markers in a plurality of the tracking images;
the identified position of the fiducial markers is used to determine the position of the tracking element at a given time.
2. The method according to claim 1 , wherein the determined position or orientation of the one or more sensor systems relative to the base structure of the scanning system, is used to replace positional information from a physical motor encoder.
3. The method according to claim 1 , wherein the object being scanned is a person.
4. The method according to claim 1 , wherein the method is for determining the position and orientation of at least one sensor system relative to the base structure of a cone beam computed tomography scanning system during scanning of an object, wherein the determining step includes determining from the one or more tracking images the position and orientation of the sensor system relative to the base structure at a given time.
5. The method according to claim 4 , wherein the determined position and orientation of the one or more sensor systems relative to the base structure of the scanning system, is used to replace positional information from a physical motor encoder.
6. The method according to claim 1 , wherein the sensor system and the one or more cameras are rotated around the object while the tracking images are obtained from the one or more cameras and medical images are obtained from the sensor system.
7. The method according to claim 6 , wherein the tracking element is fastened to the object, and the tracking element does not move relative to the base structure while the tracking images are obtained from the one or more cameras and the medical images are obtained from the sensor system.
8. The method according to claim 1 , wherein the object is not moved while the tracking images are obtained from the one or more cameras and the medical images are obtained from the sensor system.
9. The method according to claim 8 , wherein the sensor system and the one or more cameras are rotated around the object while the tracking images are obtained from the one or more cameras and medical images are obtained from the sensor system.
10. The method according to claim 9 , wherein the tracking element is fastened to the object, and the tracking element does not move relative to the base structure while the tracking images are obtained from the one or more cameras and the medical images are obtained from the sensor system.
11. A method for determining the position or orientation of at least one sensor system relative to the base structure of a cone beam computed tomography scanning system during scanning of an object, the method comprising:
obtaining one or more tracking images using one or more cameras, where the cameras are in a fixed position with respect to the sensor system; and
determining from the one or more tracking images the position or orientation of the sensor system relative to the base structure at a given time;
wherein:
a tracking element is attached to the object being scanned, the tracking element comprising one or more fiducial markers in a known configuration;
the tracking images are images taken of the tracking element;
the tracking images are processed to identify the position of the one or more fiducial markers in a plurality of the tracking images;
the identified position of the fiducial markers is used to determine the position of the tracking element at a given time; and
the determined position of the tracking element at a given time is used to determine the movement of the sensor system relative to the base structure of the scanning system during the acquisition of medical images.
12. The method according to claim 11 , wherein the tracking element and cameras define an axis of rotation of the scanner relative to the object being scanned.
13. A cone beam computed tomography system for obtaining x-ray images of at least a part of a person, the system comprising:
a stationary scanning base;
an x-ray source and an x-ray sensor movably connected to the scanning base;
a tracking element and at least one camera for acquiring images of the tracking element during scanning of the person, the at least one camera being in a fixed positional relationship with the scanning base;
wherein the system does not comprise a physical motor encoder;
wherein:
a tracking element is attached in a fixed position with respect to the stationary scanning base, the tracking element comprising one or more fiducial markers in a known configuration;
the tracking images are images taken of the tracking element;
the tracking images are processed to identify the position of the one or more fiducial markers in a plurality of the tracking images;
the identified position of the fiducial markers is used to determine the position of the tracking element at a given time.
14. The system according to claim 13 , wherein the at least one camera is in a fixed position relative to the x-ray source and/or sensor.
15. The system according to claim 13 , wherein the tracking element comprises one or more fiducial markers in a known configuration.
16. The system according to claim 13 , wherein the at least one camera is directed to look in a direction perpendicular to the direction of the x-rays.