Beam hardening correction for scanning dark field and phase contrast imaging
AssigneeKoninklijke Philips N.V.
InventorsThomas Koehler, Heiner Daerr, Ewald Roessl
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Abstract
An apparatus and related method for processing image data supplied by a scanning phase contrast or dark-field imaging apparatus (MA). Beam hardening artifact in phase contrast and dark-field imaging can be reduced by applying a beam hardening processing operation by a beam hardening processing module (BHC) in respect of a plurality of detector readings that contribute signals to the same image pixel position or geometric ray of an imaging region of the apparatus (MA). In one embodiment, a phantom body (PB) is used to acquire calibration data on which the beam hardening processing is based.
Claims12
An image signal processing system for processing data, comprising:
- a scanning radiography imager configured to provide the data, wherein the imager includes an x-ray source for emitting radiation, a detector for detecting the radiation, and an interferometer arranged at least partly between the x-ray source and the detector;
- an input port for receiving data as intensity values that correspond to one and a same geometrical ray, the intensity values being acquired using different detector pixels of the detector in a scan operation by the imager of an object or using a respective single detector pixel while at least a part of the interferometer is moved past said single detector pixel in the scan operation;
- a beam hardening processing component configured to apply, for a given image pixel position as per said geometrical ray, a beam hardening processing operation with respect to said intensity values, thereby obtaining at least one interferometric reference parameter including at least one of a reference intensity and a reference visibility for said image pixel position;
- a reconstructor configured to reconstruct from said intensity values and said at least one interferometric reference parameters at least one of a phase signal and a dark-field signal;
- and
- an output port for outputting at least one of said phase signal and said dark-field signal.
A method for processing data supplied by a scanning radiography imager having an x-ray source for emitting radiation, a detector for detecting the radiation, and an interferometer arranged at least partly between said x-ray source and said detector, the method comprising:
- receiving data as intensity values that correspond to one and a same geometrical ray, the intensity values being acquired using different detector pixels of the detector in a scan operation by the imager of an object or using a respective;
- single detector pixel while at least a part of the interferometer is moved past said single detector pixel in the scan operation;
- applying, for a given image pixel position as per said geometrical ray, a beam hardening processing operation with respect to said intensity values, thereby obtaining at least one interferometric reference parameter including at least one of a reference intensity and a reference visibility for said image pixel position;
- reconstructing from said intensity values and said at least one interferometric reference parameter at least one of a phase signal and a dark-field signal;
- and
- outputting at least one of said phase signal and said dark-field signal.
A method of producing calibration data for beam hardening effect processing in scanning phase contrast or dark-field imaging, comprising:
- acquiring calibration detector readings in a blank scan and at least one phantom scan for a given thickness of a phantom body or a plurality of phantom scans for a variable thickness of the phantom body using a detector or an x-ray source of a scanning radiography imager;
- reconstructing, per detector pixel and per thickness of the phantom body or blank scan, interferometric reference parameters from the calibration detector readings;
- and
- reconstructing, per image pixel and per the given thickness or the blank scan, a respective indicator parameter indicative of different mean attenuation levels as per the variable thickness of the phantom body or the blank scan.
A non-transitory computer-readable medium having one or more executable instructions stored thereon, which, when executed by a processor, cause the processor to perform a method for processing data supplied by a scanning radiography imager having an x-ray source for emitting radiation, a detector for detecting radiation, and an interferometer arranged at least partly between the x-ray source and the detector, the method comprising:
- receiving data as intensity values that correspond to one and a same geometrical ray, the intensity values being acquired using different detector pixels of the detector in a scan operation by the imager of an object or using a respective single detector pixel while at least a part of the interferometer is moved past the single detector pixel in the scan operation;
- applying, for a given image pixel position as per the geometrical ray, a beam hardening processing operation with respect to the intensity values, thereby obtaining at least one interferometric reference parameter including at least one of a reference intensity and a reference visibility for the image pixel position;
- reconstructing from the intensity values and the at least one interferometric reference parameter at least one of a phase signal and a dark-field signal;
- and
- outputting at least one of the phase signal and the dark-field signal.
Dependencies are inferred from the claim text.