Line Integral | | Hounsfield

Q How to reconstruct the density function from the measured integral values?

Prerequisite: Every point of the volume needs to be covered by a fan of images with at least 180 degrees capture angle.

T=Quelle X=Strahlen D=Detektor R=Rotation

From the fan of images, the following techniques reconstruct the volume from the projection images

  • Fast Fourier Transform
    • First employed method
    • No practical relevance
  • Backpropagation
    • Fast
    • Can be implemented with graphics hardware
    • Suffers from perspective widening of rays
    • “Ray hardening” leads to image smear
  • Iterative Reconstruction Methods
    • Based on difference analysis between original radiograph and simulated projections

See also “Technologien bildgebender Systeme: Computertomographie” of Prof. Dr. J├╝rgen Wohlrab.

Line Integral | | Hounsfield