Gain/lag artifact correction algorithm and software
View Patent ↗A method is described. A total number of traps to be filled in a detector of an imaging system is estimated based on a measured signal sensed by the detector. The measured signal is adjusted based on the estimated total number of traps and a current trap state of the detector. The trap state of the detector is subsequently updated.
1. A method, comprising:
estimating a total number of traps to be filled in a detector of an imaging system based on a measured signal sensed by the detector using an empirical model; and
adjusting the measured signal based on the estimated total number of traps and a current trap state of the detector,
wherein the empirical model is determined by:
providing an object adjacent to the detector of the imaging system;
projecting radiation onto the object and the detector;
collecting data from the detector over a period of time; and
estimating one or more constant parameters associated with the detector based on the collected data, the one or more constant parameters further comprising: one or more resistance value, one or more capacitance value from an RC network, the one or more resistance value representing a trap filling or trap emptying, the one or more capacitance value representing a maximum number of traps at an energy level of the radiation.
2. The method of claim 1 , further comprising:
determining a current trap state of the detector.
3. The method of claim 2 , further comprising:
determining a current number of filled traps present in the detector.
4. The method of claim 3 , further comprising:
adding an estimated missing signal to the measured signal when the current number of filled traps present in the detector is less than the estimated total number of traps to be filled by the detector.
5. The method of claim 3 , further comprising:
subtracting an estimated lag signal to the measured signal when the current number of filled traps present in the detector is greater than the estimated total number of traps to be filled by the detector.
6. The method of claim 1 , wherein the RC network includes a plurality of RC branches, each RC branch representing an energy level of the radiation.
7. The method of claim 1 , wherein adjusting further comprises:
determining a compensation signal based on the total number of traps and the current trap state of the detector; and
compensating the measured signal with the compensation signal.
8. The method of claim 1 , wherein the measured signal includes a measured signal of an image frame of the imaging system, the imaging system having a source of radiation, and the detector for sensing radiation from the source and generating data representative of the radiation.
9. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform a method for compensating a measured signal of an imaging system, the method including:
estimating a total number of traps to be filled in a detector of the imaging system based on the measured signal sensed by the detector using an empirical model; and
adjusting the measured signal based on the estimated total number of traps and a current trap state of the detector,
wherein the empirical model is determined by:
providing an object adjacent to the detector of the imaging system;
projecting radiation onto the object and the detector;
collecting data from the detector over a period of time; and
estimating one or more constant parameters associated the detector based on the collected data, the one or more constant parameters further comprising: one or more resistance value, one or more capacitance value from an RC network, the one or more resistance value representing a trap filling or trap emptying, the one or more capacitance value representing a maximum number of traps at an energy level of the radiation.
10. The method of claim 9 , further comprising:
determining a current trap state of the detector.
11. The method of claim 10 , further comprising:
determining a current number of traps present in the detector.
12. The method of claim 11 , further comprising:
adding an estimated missing signal to the measured signal when the current number of filled traps present in the detector is less than the estimated total number of traps to be filled by the detector.
13. The method of claim 11 , further comprising:
subtracting an estimated lag signal to the measured signal when the current number of filled traps present in the detector is greater than the estimated total number of traps to be filled by the detector.
14. The method of claim 9 , wherein the RC network includes a plurality of RC branches, each RC branch representing an energy level of the radiation.
15. The method of claim 9 , wherein adjusting further comprises:
determining a compensation signal based on the total number of traps and the current trap state of the detector; and
compensating the measured signal with the compensation signal.
16. The method of claim 9 , wherein the measured signal includes a measured signal of an image frame of the imaging system, the imaging system having a source of radiation, and the detector for sensing radiation from the source and generating data representative of the radiation.
17. An imaging system
a source of radiation;
a detector for sensing radiation from the source and generating data representative of the radiation; and
a processor coupled to the detector and configured to modify the data based on an estimated total number of traps and a current trap state of the detector,
wherein the processor is configured to estimate a total number of traps to be filled by the detector based on a measured signal sensed by the detector using an empirical model,
wherein the empirical model is determined by:
providing an object adjacent to the detector of the imaging system;
projecting radiation onto the object and the detector;
collecting data from the detector over a period of time; and
estimating one or more constant parameters associated the detector based on the collected data, the one or more constant parameters further comprising: one or more resistance value, one or more capacitance value from an RC network, the one or more resistance value re representing a trap filling or trap emptying, the one or more capacitance value representing a maximum number of traps at an energy level of the radiation.
18. The imaging system of claim 17 , wherein the source of radiation include an x-ray source emitting an x-ray beam.
19. The imaging system of claim 18 , wherein the detector further comprises at least one solid state x-ray detector.
20. The imaging system of claim 19 , wherein the detector further comprises a thin-film transistor (TFT), a capacitor, a photodiode, or a photoconductor.
21. The imaging system of claim 17 , wherein the processor is configured to adjust the measured signal based on the estimated total number of traps and the current trap state of the detector.
22. The imaging system of claim 21 , wherein the processor is configured to add an estimated missing signal to the measured signal when the current number of filled traps present in the detector is less than the estimated total number of traps to be filled by the detector.
23. The imaging system of claim 21 , wherein the processor is configured to subtract an estimated lag signal to the measured signal when the current number of filled traps present in the detector is greater than the estimated total number of traps to be filled by the detector.