ZHOU Ling-hong, LI Han-wei, XU Yuan etc. Geometry calibration for circular trajectory scanning in cone-beam CT[J]. Editorial Office of Optics and Precision Engineering, 2014,22(10): 2847-2854
ZHOU Ling-hong, LI Han-wei, XU Yuan etc. Geometry calibration for circular trajectory scanning in cone-beam CT[J]. Editorial Office of Optics and Precision Engineering, 2014,22(10): 2847-2854 DOI: 10.3788/OPE.20142210.2847.
Geometry calibration for circular trajectory scanning in cone-beam CT
a geometry calibration method for circular trajectory scanning in cone-beam CT was proposed to reduce the geometric artifact of a reconstructed image caused by system errors. Firstly
the properties of the projected ellipses on the detector generated by the coaxial rotating steel balls were used to deduce circular points. Then
the constraint equations of absolute conic were established based on the polar constraint condition and the intrinsic parameters were obtained by linearly calculation. Finally
the extrinsic parameters can be figured out with the geometry method and ellipse parameters based on the intrinsic parameters. Experimental results indicate that the relative precision of intrinsic parameters and the extrinsic parameters are respectively 0.193% and 0.2% while using this method to calibrate the cone-beam CT system. It concludes that the proposed calibration process is able to solve all distortion parameters
build geometric model and eliminate the artifacts caused by the misaligned geometry on the reconstruction images.The method is characterized by simpler modelling
stronger application ability
and could be used in all circular orbit CTs.
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references
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