Beam detection and filtering noise
A digital radiographic detector outputs positive read out signals that may oscillate. The presence of negative going portions of the read out signals may be used to determine that the detected positive signals are a result of noise, while an absence of the negative going portions may be used to determine that x-rays are impacting the detector.
1. A method of operating a digital radiographic detector that includes a plurality of imaging pixels disposed in rows and columns, the method comprising:
monitoring an output signal from each of a plurality of individual adjacent strips of the imaging pixels of the detector, wherein the individual adjacent strips each consist of a preselected portion of one of a plurality of adjacent rows of the imaging pixels;
when detecting one or more only positive signals in the output signals that satisfy a preset positive threshold, determining that the detected one or more only positive signals are caused by x-rays impacting the imaging pixels; and
when detecting one or more negative signals in the output signals that satisfy a preset negative threshold, determining that any detected positive signals are not caused by x-rays impacting the imaging pixels.
2. The method of claim 1 , wherein the step of detecting one or more only positive signals further comprises:
measuring a magnitude of the detected one or more only positive signals; and
determining that the magnitude of the detected one or more only positive signals satisfies the preset positive threshold.
3. The method of claim 2 , further comprising:
determining a number of the detected one or more only positive signals whose magnitude satisfies the preset positive threshold; and
determining that the number of the detected one or more only positive signals whose magnitude satisfies the preset positive threshold also satisfies a preset number threshold.
4. The method of claim 2 , wherein the step of measuring further comprises determining a statistical measure of the magnitude of the detected one or more only positive signals.
5. The method of claim 1 , further comprising:
capturing radiographic image data in the detector; and
storing the captured radiographic image data for diagnostic purposes based upon the step of determining that the detected one or more only positive signals are caused by x-rays impacting the imaging pixels.
6. A method of operating a digital radiographic detector that includes a plurality of imaging pixels disposed in rows and columns, the method comprising:
monitoring output signals from each of a plurality of individual adjacent strips of the imaging pixels of the detector, wherein the individual adjacent strips each consist of a preselected portion of one of a plurality of adjacent rows of the imaging pixels;
when detecting only positive signals in the output signals that satisfy a preset positive threshold, determining that the detected positive signals are caused by x-rays impacting the imaging pixels; and
when detecting negative signals in the output signals that satisfy a preset negative threshold, determining that any detected positive signals are not caused by x-rays impacting the imaging pixels.
7. The method of claim 6 , wherein the step of detecting negative signals further comprises:
measuring a magnitude of the detected negative signals; and
determining that the magnitude of the detected negative signals are greater than a preset negative threshold.
8. The method of claim 7 , further comprising:
determining a number of the detected negative signals whose magnitude are greater than the preset negative threshold; and
determining that the number of the detected negative signals whose magnitude are greater than the preset negative threshold also satisfy a preset number threshold.
9. The method of claim 7 , wherein the step of measuring further comprises determining a statistical measure of the magnitude of the detected negative signals.
10. The method of claim 6 , further comprising:
capturing a frame of radiographic image data in the detector; and
discarding the frame of radiographic image data based upon the step of determining that any detected positive signals are not caused by x-rays impacting the imaging pixels.
11. A method of operating a digital radiographic detector that includes a plurality of imaging pixels disposed in rows and columns, the method comprising:
monitoring output signals from a plurality of imaging pixel windows, wherein the imaging pixel windows each consist of a portion of each of two or more adjacent rows of the imaging pixels;
when detecting only positive signals in the output signals that satisfy a preset positive threshold, determining that the detected only positive signals are caused by x-rays impacting the imaging pixels; and
when detecting negative signals in the output signals that satisfy a preset negative threshold, determining that any detected positive signals are not caused by x-rays impacting the imaging pixels.
12. The method of claim 11 , wherein the step of detecting negative signals further comprises:
measuring a magnitude of the detected negative signals; and
determining that the magnitude of the detected negative signals are greater than a preset negative threshold.
13. The method of claim 12 , further comprising:
determining a number of the detected negative signals whose magnitude are greater than the preset negative threshold; and
determining that the number of the detected negative signals whose magnitude are greater than the preset negative threshold also satisfy a preset number threshold.
14. The method of claim 12 , wherein the step of measuring further comprises determining a statistical measure of the magnitude of the detected negative signals.
15. The method of claim 11 , further comprising:
capturing a frame of radiographic image data in the detector; and
discarding the frame of radiographic image data based upon the step of determining that any detected positive signals are not caused by x-rays impacting the imaging pixels.
16. The method of claim 11 , wherein the step of detecting only positive signals further comprises:
measuring a magnitude of the detected only positive signals; and
determining that the magnitude of the detected only positive signals satisfies the preset positive threshold.
17. The method of claim 16 , further comprising:
determining a number of the detected only positive signals whose magnitude satisfies the preset positive threshold; and
determining that the number of the detected only positive signals whose magnitude satisfies the preset positive threshold also satisfies a preset number threshold.
18. The method of claim 16 , wherein the step of measuring further comprises determining a statistical measure of the magnitude of the detected only positive signals.
19. The method of claim 11 , further comprising:
capturing radiographic image data in the detector; and
storing the captured radiographic image data for diagnostic purposes based upon the step of determining that the detected only positive signals are caused by x-rays impacting the imaging pixels.