System and method for sampling frequency adjustment for radiation imaging system
Among other things, one or more techniques and/or systems are described for setting a sampling frequency for a radiation imaging system. The radiation imaging system comprises a rotating gantry configured to rotate a radiation source and a detector array about an object to generate an image(s) of the object. A data acquisition system is configured to sample the detector array as views. One or more flag structures are arranged according to a partial arc segment (e.g., a structure less than a full 360 degree circle). One or more sensors are disposed on one of the rotating gantry or a stationary support about which the rotating gantry rotates. When a sensor encounters a flag structure, a current rotational speed of the rotating gantry is determined. A clock frequency is updated based upon the current rotational speed to establish a sampling frequency for the data acquisition system for sampling the detector array.
1. A radiation imaging system comprising:
a set of sensors disposed on one of a rotating gantry or a stationary support about which the rotating gantry rotates;
a first flag structure disposed relative to the other of the rotating gantry or the stationary support of the radiation imaging system; and
a data acquisition system configured to:
upon a sensor of the set of sensors encountering the first flag structure:
determine a current rotational speed of the rotating gantry; and
set a clock frequency of a clock based upon the current rotational speed, wherein the clock frequency establishes a sampling frequency for the data acquisition system of the radiation imaging system for samples taken between an encounter with the first flag structure and an encounter with a next flag structure.
2. The radiation imaging system of claim 1 , comprising a second flag structure, and the data acquisition system configured to:
upon the sensor encountering the second flag structure:
determine a new current rotational speed of the rotating gantry; and
update the clock frequency based upon the new current rotational speed.
3. The radiation imaging system of claim 1 , the data acquisition system configured to:
upon a second sensor of the set of sensors encountering the first flag structure:
determine a new current rotational speed of the rotating gantry; and
update the clock frequency based upon the new current rotational speed.
4. The radiation imaging system of claim 1 , comprising a second flag structure, wherein the first flag structure and the second flag structure have a same size.
5. The radiation imaging system of claim 1 , comprising a second flag structure, wherein the first flag structure has a first size and the second flag structure has a second size different than the first size.
6. The radiation imaging system of claim 5 , wherein the data acquisition system is configured to:
determine a current position of the rotating gantry based upon determining that a flag structure traversed by the sensor has the first size and not the second size.
7. The radiation imaging system of claim 1 , wherein the data acquisition system is configured to:
determine a size of a flag structure based upon a width of a pulse detected by the sensor.
8. The radiation imaging system of claim 1 , wherein a plurality of flag structures are positioned according to a partial arc segment.
9. The radiation imaging system of claim 8 , wherein a flag structure of the plurality of flag structures is designated as a home position.
10. A radiation imaging system comprising:
an ionizing radiation source;
a detector array comprising a plurality of detector cells configured to detect radiation emitted by the ionizing radiation source;
a data acquisition system electrically coupled to the detector array and configured to sample the plurality of detector cells according to a sampling frequency;
a rotating gantry upon which the ionizing radiation source and the detector array are mounted;
a stationary support;
a set of sensors disposed on one of the rotating gantry or the stationary support; and
a set of flag structures disposed relative to the other of the rotating gantry or the stationary support and spaced apart to define a partial arc segment, wherein the data acquisition system is configured to:
upon a sensor of the set of sensors encountering a flag structure of the set of flag structures that begins a first partial arc segment portion of the partial arc segment:
determine a current rotational speed of the rotating gantry; and
set a clock frequency of a clock based upon the current rotational speed.
11. The radiation imaging system of claim 10 , wherein a first flag structure of the set of flag structures has a first size and a second flag structure of the set of flag structures has a second size different than the first size.
12. The radiation imaging system of claim 11 , the data acquisition system configured to:
detect traversal of the first flag structure based upon a width, of a pulse detected by the sensor, indicative of the first size; and
determine a current location of the rotating gantry based upon detecting traversal of the first flag structure.
13. The radiation imaging system of claim 10 , the data acquisition system configured to:
upon identifying a rising edge of a pulse detected by the sensor, determine the current rotational speed; and
upon identifying a falling edge of the pulse detected by the sensor, set the clock frequency.
14. The radiation imaging system of claim 10 , wherein the sensor is an optical sensor.
15. The radiation imaging system of claim 10 , wherein the set of flag structures comprise a first flag structure and a second flag structure, the first flag structure positioned 45 degrees from the second flag structure.
16. The radiation imaging system of claim 10 , wherein the set of flag structures comprise a first flag structure, a second flag structure, and a third flag structure, the first flag structure positioned 30 degrees from the second flag structure and the second flag structure positioned 30 degrees from the third flag structure.
17. A method for setting a sampling frequency for a radiation imaging system, the method comprising:
upon identifying a first pulse detected by a first sensor disposed on one of a rotating gantry or a stationary support about which the rotating gantry rotates:
determining a first current rotational speed of the rotating gantry;
setting a clock frequency of a clock based upon the first current rotational speed, wherein the clock frequency establishes a first sampling frequency for a data acquisition system of the radiation imaging system for samples taken between an identification of the first pulse and an identification of a next pulse; and
upon identifying a second pulse detected by a second sensor:
determining a second current rotational speed of the rotating gantry; and
updating the clock frequency of the clock to an updated clock frequency based upon the second current rotational speed, wherein the updated clock frequency establishes a second sampling frequency for the data acquisition system of the radiation imaging system for samples taken between identification of the second pulse and an identification of a second next pulse.
18. The method of claim 17 , comprising:
determining the first current rotational speed upon detecting a rising edge of the first pulse.
19. The method of claim 17 , comprising:
setting the clock frequency upon detecting a falling edge of the first pulse.
20. The method of claim 17 , comprising:
identifying a first width of the first pulse as corresponding to a first size of a first flag structure; and
identifying a second width of the second pulse as corresponding to a second size, different than the first size, of a second flag structure.