Projection truncation processing for CBCT
AssigneeCarestream Health, Inc.
InventorsDong Yang, Robert A. Senn
Life of this patent
Estimating the term…
Abstract
A method for 3-D volume image reconstruction of a subject. 2-D projection images are obtained over a range of scan angles, and one or more truncated images are identified from the obtained images. From each of the one or more truncated images, a corrected truncated image is formed by a repeated process of identifying a row of image data values in the one or more truncated images, assigning an extension length to one or both ends of the row according to the row location in the truncated image, and extending the truncated image data for the row of image data values by applying a row-dependent cosine function to each value in the extension length. A 3-D volume image is reconstructed using one or more of the corrected truncated images.
Claims5
A method for 3-D volume image reconstruction of a subject, comprising:
- obtaining a plurality of 2-D projection images over a range of scan angles using partial scan cone-beam computed tomography;
- identifying, by a computer processor, one or more truncated projected images along a horizontal direction in one or more truncated images across all of the view of the plurality of 2-D projection images;
- forming, by the computer processor, from each of the one or more truncated projected images, a corrected truncated projection image by a repeated process comprising:
- (i) adaptively assigning an extension length for the rows that are truncated in the current truncated projection images;
- (ii) identifying the truncated projection view that has the largest extended length;
- (iii) recalculating the scanning fan angle based on the largest extended length calculated in step (i);
- (iv) applying an adjusted weighting factor based on the recalculated scanning fan angle;
- (v) extending the truncated projection image data for the rows that are truncated in the current truncated projection image by applying a cosine function to each value in the extension length;
- and
- reconstructing, by the computer processor, the 3-D volume image incorporating the corrected truncated projection images;
- wherein forming the corrected truncated projected image further comprises adjusting a weighting factor by increasing an x-ray fan angle value to calculate weighting coefficients for an increased range of angles;
- and
- wherein the cosine function is a first cosine function and wherein assigning the extension length comprises applying a second cosine function according to row location in the projected image.
Dependencies are inferred from the claim text.