Octopus Reconstruction - Phase Contrast Module

Besides X-ray attenuation, the refraction of X-rays becomes an important aspect in high-resolution X-ray CT as well. When no image processing is used, the X-ray refraction gives rise to an edge enhancement artifact, which often hinders proper image interpretation, segmentation and analysis.

To cope with these artifacts, Octopus offers an add-on module which includes three different algorithms to reduce the imaging artifacts and improve image quality. The different algorithms have their specific strengths and can be used to complement each other. While the two so-called phase retrieval algorithms have the ability to increase the signal-to-noise ratio in the reconstructed images, this comes at the cost of a slight smoothing of the edges. The so-called phase-correcting algorithm on the other hand maintains the detail visibility in the images while removing the edge-enhancement artifacts.


  • The improved signal-to-noise ratio due to phase retrieval
  • An unfiltered (left) and filtered (right) slice of a sandstone rock
  • A zoom of a wood sample. Left: unfiltered; middle: phase retrieval; right: phase correction
  • A reconstructed slice of a pharmaceutical bead. Left: unfiltered; middle: phase corrected; right: phase retrieved