CPC G06T 11/006 (2013.01) [A61B 6/032 (2013.01); G01N 23/046 (2013.01); G01N 2223/419 (2013.01); G06T 2207/10081 (2013.01); G06T 2207/20061 (2013.01); G06T 2211/421 (2013.01)] | 12 Claims |
1. A method comprising using at least one hardware processor to reconstruct a computed tomography (CT) image by:
performing a filtered back projection on a sinogram,
wherein back projection in the filtered back projection comprises
transitioning the sinogram to a linogram using linear interpolation, wherein the linogram represents each line as two points (s, t) lying on boundaries of an N×N square area, wherein N is a linear size of the CT image, wherein the linogram comprises an N×N image for each of a plurality of types of lines, wherein the plurality of types of lines comprise mostly vertical lines with a positive shift, mostly vertical lines with a negative shift, mostly horizontal lines with a positive shift, and mostly horizontal lines with a negative shift, wherein mostly vertical lines with a positive shift comprise lines corresponding to coordinates in the sinogram with a normal slope θ between 3π/4 and π, mostly vertical lines with a negative shift comprise lines corresponding to coordinates in the sinogram with the normal slope θ between 0 and π/4, mostly horizontal lines with a positive shift comprise lines corresponding to coordinates in the sinogram with the normal slope θ between π/2 and 3π/4, and mostly horizontal lines with a negative shift comprise lines corresponding to coordinates in the sinogram with the normal slope θ between π/4 and π/2, and
performing an inverse Fast Hough Transform on the linogram to produce the reconstructed CT image, and
wherein filtering in the filtered back projection uses an infinite impulse response (IIR) filter.
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