Patent Number: 
Section: claims

1. A system to position a filter in an imaging system, comprising:a plate defining an aperture through the plate;a filter frame having at least a first filter holding portion operable to move relative to the aperture;a movement system configured to move the filter frame relative to the aperture, the movement system having:a motor;a single rail extending between a first end and a second end and positioned relative to the aperture, wherein the single rail extends along a first side of the filter frame;a shaft configured to be rotated by the motor, wherein the shaft extends along a second side of the filter frame opposed to the first side; anda connection member coupling the shaft to the filter frame, wherein the connection member is operable to move the filter frame relative to the rail when the shaft is rotated by the motor. 2. The system of claim 1, further comprising:a position determining assembly coupled to the shaft and operable to sense a rotation of the shaft. 3. The system of claim 2, wherein the position determining assembly further comprises:a position determination module connected to the sensor;a communications link;an input portion operable to be sensed by the sensor;wherein the input portion is axially fixed to the shaft. 4. The system of claim 1, further comprising:a filter member carried by the filter frame at the first filter holding portion;wherein the filter member includes a plurality of slots extending therethrough operable to be precisely positioned relative to the aperture. 5. The system of claim 1, further comprising:a bushing having a first engaging surface and a second engaging surface;wherein the first engaging surface extends at an angle relative to the second engaging surface;wherein the first engaging surface engages a first surface of the filter frame and the second engaging surface engages a second surface of the filter frame. 6. The system of claim 1, further comprising:a processor;wherein the position determining module is operable to generate an index pulse when the filter frame is at a home position;wherein the index pulse is transmitted as an index signal to the processor;wherein the processor is operable to determine that the at least first filter holding portion is at a home position based on the index signal. 7. The system of claim 6, wherein the processor is further operable to receive a position signal from the position determining module;wherein the processor is operable to execute instructions to determine a position of the at least a first filter holding portion relative to the aperture. 8. The system of claim 1, wherein the shaft includes a first thread and the connection member includes a second thread, the second thread engaging the first thread to enable the connection member to move relative to the shaft when the shaft is rotated by the motor. 9. The system of claim 1, wherein the connection member has (i) threads to engage threads on the shaft and (ii) a filter frame connection. 10. A system to position a filter in an imaging system, comprising:a plate defining an aperture through the plate;a single rail extending between a first end and a second end and fixed relative to the mounting plate;a motor;a shaft configured to be rotated by the motor;a connection member configured to engage the shaft, wherein the connection member is operable to move relative to the rail when the shaft is rotated by the motor;a filter frame having at least a first filter holding portion; anda position determining module;wherein the position determining module includes a sensor operable to sense a rotation of the shaft. 11. The system of claim 10, further comprising:a position determination system comprising at least the position determining module and an input portion;wherein the input portion is fixed to the shaft. 12. The system of claim 10, wherein the single rail is on an opposite side of the filter frame from the shaft;wherein the filter frame is moveably connected to the shaft through the connection member and the single rail;wherein the single rail is only one rail. 13. The system of claim 12, wherein the shaft rotates relative to the single rail, but is linearly fixed relative to the single rail. 14. The system of claim 10, further comprising:a bushing having a first engaging surface and a second engaging surface;wherein the first engaging surface extends at an angle relative to the second engaging surface;wherein the first engaging surface engages a first surface of the filter frame and the second engaging surface engages a second surface of the filter frame. 15. The system of claim 10, wherein the positioning determining module is spaced away from the motor and fixedly connected to the shaft. 16. The system of claim 10, further comprising:a filter member having at least a first through slot, a second through slot, and a third through slot;wherein the first through slot, the second through slot, and the third through slot are spaced apart and configured to be positioned over the aperture with the rotation of the shaft. 17. The system of claim 10, wherein the shaft includes a first thread and the connection member includes a second thread, the second thread engaging the first thread to enable the connection member to move relative to the shaft when the shaft is rotated by the motor. 18. A method of positioning a filter in an imaging system, comprising:operating a motor system to rotate a shaft;engaging and moving a connection member that is fixed to a frame member by engaging the shaft with the connection member;moving the frame member along a rail fixed relative to the shaft;sensing a position of the frame member based on rotation of the shaft; andpositioning the frame member relative to an aperture. 19. The method of claim 18, further comprising:operating a control system to select a filter to filer an imaging beam;transmitting a selected filter position;wherein operating the motor system to rotate the shaft includes rotating the shaft to move the frame member to a selected position. 20. The method of claim 18, further comprising:movably fixing the frame member so only a single rail member.