Method for reducing direct hit artifacts and x-ray facility
AssigneeSiemens Aktiengesellschaft
InventorBoris Stowasser
Life of this patent
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Abstract
A method for reducing artifacts produced by x-ray radiation directly striking a measuring pixel of a CMOS detector after crossing a scintillator, wherein, for an x-ray image recorded using the CMOS detector, artifact image points are extracted by applying a local, edge-obtaining smoothing operator that evaluates image data of neighboring image points located in the vicinity of a considered image point and comparison with the image to which the smoothing operator was applied, and their image data is corrected.
Claims21
A method for reducing artifacts produced by x-ray radiation directly striking a measuring pixel of a CMOS detector after crossing a scintillator, comprising:
- extracting artifact image points from an x-ray image profile recorded using the CMOS detector by performing an iterative process including one or more executions of the following steps:
- applying a local, edge-obtaining smoothing operator that evaluates image data of neighboring image points located in the vicinity of a considered image point to generate a smoothed image profile,
- calculating a differential image by subtracting the smoothed image profile from the x-ray image profile to which the smoothing operator was applied,
- comparing the calculated differential image to a threshold value,
- identifying artifact image points based on the results of the comparison of the calculated differential image to the threshold value, and
- for each identified artifact image point, adjusting but not deleting the image data associated with that artifact image point based on the threshold value to generate a correction image, wherein the adjustment of the image data comprises reducing a magnitude of a peak associated with the artifact image point to a reduced magnitude that corresponds with the threshold value used for identifying the artifact image point;
- and
- using the correction image including the adjusted but not deleted image data associated with the identified artifact image points to correct the x-ray image profile.
An x-ray facility comprising:
- a CMOS detector having a scintillator and a pixel matrix with measuring pixels for receiving secondary radiation generated in the scintillator, and
- a computation device configured to:
- extract artifact image points from an x-ray image profile recorded using the CMOS detector by performing an iterative process including one or more executions of the following steps:
- applying a local, edge-obtaining smoothing operator that evaluates image data of neighboring image points located in the vicinity of a considered image point to generate a smoothed image profile,
- calculating a differential image by subtracting the smoothed image profile from the x-ray image profile to which the smoothing operator was applied,
- comparing the calculated differential image to a threshold value,
- identifying artifact image points based on the results of the comparison of the calculated differential image to the threshold value, and
- for each identified artifact image point, adjusting but not deleting the image data associated with that artifact image point based on the threshold value to generate a correction image, wherein the adjustment of the image data comprises reducing a magnitude of a peak associated with the artifact image point to a reduced magnitude that corresponds with the threshold value used for identifying the artifact image point;
- and
- use the correction image including the adjusted but not deleted image data associated with the identified artifact image points to correct the x-ray image profile.
Dependencies are inferred from the claim text.