Patent Number: 
Section: claims

1. An apparatus for modifying a radiation beam between a radiation source and a radiation detector, based on an object to be imaged using the radiation beam, the apparatus comprising:at least one collimator that attenuates radiation that is incident upon the collimator; andat least one motor operable to move the collimator, during a single continuous radiation exposure that is detected by the radiation detector, along a predefined path relative to a radiation axis defined by the direction that radiation travels from the radiation source to through the object to be imaged and to the radiation detector;wherein the apparatus has a closed position wherein the collimator blocks the radiation axis so that no portion of a radiation beam from the radiation source can pass by the collimator to reach the object;wherein the motor is operable to move the collimator along the predefined path between the closed position and a plurality of open positions, either continuously or by discrete steps, during the single continuous radiation exposure, wherein in each open position a different portion of the object is exposed to radiation from the radiation source passing by the collimator and detected by the radiation detector; andwherein the motor is synchronized with an exposure start time and an exposure end time of the radiation source, the start time and end time being fora the single continuous radiation exposure, such that the motion of the collimator permits varying amounts of radiation from the radiation source to reach each portion of the object during the single continuous radiation exposure, wherein the varying amounts of radiation are based at least in part on a shape of the object and an orientation of the object relative to the radiation source. 2. The apparatus of claim 1, wherein the at least one collimator blocks substantially all radiation that is incident upon the at least one collimator from the radiation source. 3. The apparatus of claim 1, wherein the at least one collimator allows a substantial portion of the radiation that is incident upon at least one collimator from the radiation source to pass by the at least one collimator and reach the target, wherein the material and thickness of the at least one collimator are selected to attenuate a specific amount of the radiation. 4. The apparatus of claim 1, wherein the at least one collimator comprises first and second collimators, and wherein the first and second collimators have opposing edges that are adjacent to each other in the closed position, and the opposing edges are straight and parallel. 5. The apparatus of claim 1, wherein the at least one collimator comprises first and second collimators, and wherein the first and second collimators have opposing edges that are adjacent to each other in the closed position, and the opposing edges are curved. 6. The apparatus of claim 1, wherein the at least one collimator comprises first and second collimators, and wherein:the at least one motor is operable to move the first and second collimators apart from each other along the predefined paths from the closed position to the plurality of increasingly spaced apart open positions, wherein in each open position an increasingly greater portion of the radiation beam from the radiation source is permitted to pass through the apparatus between the first and second collimators to the object; orthe at least one motor is operable to move the first and second collimators toward each other along the predefined paths from an initial open position to a plurality of decreasingly spaced apart open positions, wherein in each successive open position a decreasingly lesser portion of the radiation beam from the radiation source is permitted to pass through the apparatus between the first and second collimators to the object. 7. The apparatus of claim 1, wherein the at least one collimator moves along a predefined curved path about a pivot axis, the pivot axis being transverse to the radiation axis. 8. The apparatus of claim 7, wherein the at least one collimator comprises a curved plate, such that a major surface of the plate has a curvature centered on the pivot axis of the collimator. 9. The apparatus of claim 1, wherein the at least one collimator moves along a predefined linear path that is transverse to the radiation axis. 10. A method for controlling radiation exposure across a target object during a radiographic imaging exposure, the method comprising:positioning an adaptive filter between a radiation source and a radiation detector with a target object being between the adaptive filter and the radiation detector, wherein the adaptive filter comprises at least one collimator that attenuates radiation that is incident upon the collimator; andmoving the at least one collimator during a single continuous radiation emission from the radiation source and detected by the radiation detector, such that the motion of the at least one collimator allows different amounts of radiation from the radiation source to pass by the at least one collimator to each portion of the target object during the single continuous radiation emission, wherein the different amounts of radiation allowed to reach each portion of the target object are based at least in part on a shape of the target object and an orientation of the target object relative to the radiation source and the adaptive filter;wherein the at least one collimator begins to move at a first predetermined time after the radiation source begins to emit radiation toward the target object during the single continuous radiation emission, and the at least one collimator reaches a maximum movement distance at a second predetermined time before the radiation source stops emitting radiation toward the target object that is detected by the radiation detector. 11. The method of claim 10, wherein moving the at least one collimator comprises pivoting the at least one collimator along a curved path about a common pivot axis, the common pivot axis being transverse to an axis of the radiation emission. 12. The method of claim 10, wherein the method comprises generating a movement profile for the at least one collimator, wherein the movement profile is based on a cross-sectional shape of the target object and the orientation of the target object relative to the radiation source and the adaptive filter. 13. The method of claim 12, wherein the movement profile is also based on a radius from a pivot axis of the adaptive filter to the at least one collimator. 14. The method of claim 12, wherein the movement profile causes the target object to receive a radiation exposure profile across a width of the target object that is generally proportional to a thickness profile of the target object across the width of the target object. 15. The method of claim 10, wherein moving the at least one collimator comprises moving the at least one collimator in a plurality of small steps such that the at least one collimator stops or slows briefly between each step. 16. The method of claim 15, wherein the plurality of small step comprises at least 30 steps, or the at least one collimator stops for 1 millisecond or less between each step, or the at least collimator pivots 1° or less between each successive step. 17. The method of claim 10, further comprising combining an image acquired from the radiographic imaging procedure with the adaptive filter and a target object with a reference image acquired with the same adaptive filter motion but without the object to produce an image that looks like a raw radiographic image that would have been produced under the same imaging circumstances if the adaptive filter was not present in the imaging system. 18. The method of claim 10, wherein the single continuous radiation emission is one of a plurality of sequential radiation emissions targeting the target object during a radiographic imaging procedure;wherein the plurality of sequential radiation emissions are temporally separated by brief non-radiation periods with no radiation emission, during which the radiation source, the target object, or both, are moved or adjusted; andwherein during each of the plurality of sequential radiation emissions, the at least one collimator begins to move at a first predetermined time after the radiation source begins to emit radiation toward the target object, and the at least one collimator reaches a maximum movement distance at a second predetermined time before the radiation source stops emitting radiation toward the target object. 19. The method of claim 10, wherein the at least one collimator comprises first and second collimators, and wherein moving the at least one collimator comprises moving the first and second collimators apart from or toward each other by moving the first and second collimators in opposite directions along linear paths transverse to an axis of the radiation emission. 20. A system comprising:a radiation source;a radiation detector; andan adaptive filter positioned between the radiation source and the radiation detector, wherein the adaptive filter comprises first and second collimators that attenuate radiation that is incident upon the collimators;wherein the system is configured to include a target object positioned between the adaptive filter and the radiation detector such that the target object can be radiologically imaged; andwherein the system is operable to move the first and second collimators apart from or toward each other during a single continuous radiation emission from the radiation source that is detected by the radiation detector, such that the motion of the collimators allows different amounts of radiation from the radiation source to pass between the two collimators to each portion of the target object during the single continuous radiation emission, wherein the different amounts of radiation allowed to reach each portion of the target object are determined based on a thickness of each portion of the target object, as measured in the direction the radiation travels, such that the radiation detector receives a more uniform distribution of radiation through the target object. 21. The system of claim 20, wherein the system is operable to move the first and second collimators apart from or toward each other in opposite directions along curved paths about a common pivot axis. 22. The system of claim 20, wherein the first and second collimators begin to move apart from or toward each other at a predetermined time after the radiation source begins to emit radiation toward the target object, and the first and second collimators reach a maximum or minimum separation from each other at a predetermined time before the radiation source stops emitting radiation toward the target object.