Automatic adaptive soft tissue thresholding for two-pass CT cone-beam artifact reduction
AssigneeKoninklijke Philips Electronics N.V.
InventorsPeter Forthmann, Michael Grass, Roland Proksa
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Abstract
Since the soft tissue levels in an image usually comprise a variety of values between air and bone boundaries, it may not be obvious a priori what threshold value applies. According to an exemplary embodiment of the present invention, an examination apparatus is provided which is adapted for determining the optimal weight for subtraction of a soft tissue correction image without performing a multitude of forward and backward projections. This may be provided determining a roughness function based on a plurality of subtractions of the soft tissue streak image, each subtraction corresponding to a different weighting of the streak image.
Claims20
An examination apparatus for examination of an object of interest, the examination apparatus comprising:
- a calculation unit that creates a first streak-only image on a basis of a first segmentation of a first region from a reconstructed image of the object of interest;
- creates a second streak-only image on a basis of a second segmentation of a second region from the reconstructed image;
- subtracts the second streak-only image from the reconstructed image, resulting in a corrected reconstructed image;
- and subtracts the first streak-only image, weighted by a first weighting value, from the corrected reconstructed image, thereby performing an adaptive artifact reduction on the basis of a roughness function, resulting in a final image of the object of interest;
- wherein the roughness function is based on the first weighting value applied to the first streak-only image;
- and wherein the final image corresponds to a minimum of the roughness function.
An image processing device for examination of an object of interest, the image processing device comprising:
- a memory for storing data of the object of interest;
- a calculation unit that performs an adaptive artifact reduction on the basis of a roughness function, resulting in a final image of the object of interest;
- wherein the roughness function is based on at least one weighting value applied to a first streak-only image;
- and wherein the final image corresponds to a minimum of the roughness function;
- wherein the calculation unit:
- creates the first streak-only image on the basis of a first segmentation of a first region from a reconstructed image of the object of interest;
- creates a second streak-only image on the basis of a second segmentation of a second region from the reconstructed image;
- subtracts the second streak-only image from the reconstructed image, resulting in a corrected reconstructed image;
- subtracts the first streak-only image, weighted by a first weighting value, from the corrected reconstructed image.
A method of examination of an object of interest, the method comprising the step of:
- performing an adaptive artifact reduction on the basis of a roughness function, resulting in a final image of the object of interest;
- wherein the roughness function is based on at least one weighting value applied to a first streak-only image;
- and wherein the final image corresponds to a minimum of the roughness function;
- wherein the adaptive artefact reduction comprises the steps of:
- creating the first streak-only image on the basis of a first segmentation of a first region from a reconstructed image of the object of interest;
- creating a second streak-only image on the basis of a second segmentation of a second region from the reconstructed image;
- subtracting of the second streak-only image from the reconstructed image, resulting in a corrected reconstructed image;
- subtracting the first streak-only image, weighted by a first weighting value, from the corrected reconstructed image.
A non-transitory computer-readable medium encoded with computer readable instructions which, when executed by a processor, causes the processor to:
- perform an adaptive artifact reduction on a basis of a roughness function, resulting in a final image of an object of interest;
- wherein a roughness function is based on at least one weighting value applied to a first streak-only image;
- and wherein the final image corresponds to a minimum of the roughness function;
- in which the processor
- creates the first streak-only image on the basis of a first segmentation of a first region from a reconstructed image of the object of interest;
- creates a second streak-only image on the basis of a second segmentation of a second region from the reconstructed image;
- subtracts of the second streak-only image from the reconstructed image, resulting in a corrected reconstructed image;
- subtracts the first streak-only image, weighted by a first weighting value, from the corrected reconstructed image.
Dependencies are inferred from the claim text.