Adaptive frame scanning scheme for pulsed X-ray imaging
View Patent ↗A method for adaptive frame scanning for pulsed x-ray imaging comprising the steps of: scanning lines on an image detector sequentially; receiving an indication that radiation is about to begin; waiting a fixed delay after the indication is received; suspending scanning after the fixed delay has lapsed; and resuming scanning of lines on the detector upon receiving an indication that radiation has stopped. By monitoring for completion of a frame a predetermined frame delay can be added before commencing the next line scan to accommodate jitter in the radiation pulse timing.
1. A method for adaptive frame scanning for pulsed X-ray imaging of X-ray radiation delivered in a sequence of pulses having an X-ray pulsing period, the method comprising the steps of:
scanning lines on an image detector sequentially, wherein the lines on the image detector are scanned in a frame scan time, and wherein the frame scan time is longer than the X-ray pulsing period;
receiving an indication that the radiation is about to begin;
waiting a fixed delay after the indication that the radiation is about to begin is received;
suspending scanning lines on the image detector after the fixed delay has lapsed, wherein scanning lines on the image detector is suspended before the radiation begins;
resuming scanning lines on the image detector upon receiving an indication that the radiation has stopped.
2. The method of claim 1 , wherein the step of waiting a fixed delay comprises waiting until at least one scan line time prior to receiving an indication that radiation has begun.
3. The method of claim 1 further comprising:
monitoring for completion of a frame; and,
adding a predetermined frame delay upon completion of a frame before commencing the next line scan.
4. The method of claim 3 wherein the predetermined frame delay is calculated to accommodate jitter in actual radiation-on times to obtain a fixed frame rate.
5. The method of claim 1 further comprising:
sensing gain calibration;
employing frame scans from the beginning of radiation to the end of radiation plus a post frame after elapse of radiation gain correction by an analysis system.
6. The method of claim 1 further comprising:
sensing Cine imaging;
employing frame scans from the beginning of radiation to the end of radiation plus a post-frame after elapse of radiation gain for image generation.
7. The method of claim 1 further comprising:
operating the detector in an alternate mode;
monitoring switching of the X-ray source from standby to “on” mode; and
resetting the control scan generator to stop line scanning at least one frame prior to the delay from the indication that radiation is about to begin.
8. The method of claim 7 in which the on mode is determined by the control scan generator responsive to a flag from the X-ray generator that radiation is imminent.
9. A system for control of an X-ray image detector comprising:
an x-ray source;
a signal generator connected to the X-ray source and capable of providing a first signal indicating that radiation is about to begin and a second signal that radiation has stopped;
a detector frame scan signal generator capable of receiving the first and second signals from the signal generator, waiting a delay responsive to the first signal, providing a first control signal to suspend line scanning responsive to the delay, and providing a second control signal to activate line scanning responsive to the second signal from the signal generator.
10. The system of claim 9 wherein the detector frame scan signal generator provides a control signal to suspend line scanning substantially equal to at least one scan line time prior to receiving an indication that radiation has begun.
11. The system of claim 9 wherein the detector frame scan signal generator is capable of monitoring for completion of a frame and provide a third control signal to activate line scanning for adding a predetermined frame delay upon completion of a frame before commencing the next line scan.
12. The system as defined in claim 11 wherein the predetermined frame delay is calculated to accommodate jitter in actual radiation on times to obtain a fixed frame rate.
13. The system as defined in claim 9 wherein the X-ray image detector is capable of operating in an alternate mode and the detector frame scan signal generator is further capable of monitoring switching of the X-ray source from standby to “on” mode; and resetting to stop line scanning at least one frame prior to the delay from the pre-radiation on pulse.
14. The system as defined in claim 13 in which the on mode is determined by the detector scan signal generator responsive to an active signal generated by the signal generator associated with the X-ray source.
15. A method of scanning an imaging array used to convert incident X-rays into electrical signals, wherein the X-rays are delivered in a sequence of pulses, and wherein a warning signal is generated at a first time interval prior to the delivery of each X-ray pulse, said method comprising the steps of:
(a) initiating the scanning of the array at the end of an X-ray pulse;
(b) upon detection of the warning signal, continuing the scanning of the array for a second time interval shorter than said first interval and then halting the scanning of the array; and
(c) repeating steps (a) and (b).
16. A method as recited in claim 15 , wherein the second time interval is selected so that time between the end of the second time interval and the end of the first time interval is about equal to the time it takes to scan one line of the imaging array.