Katsevich-type reconstruction for dual helical cone-beam CT.

This paper is about inspecting large and long object using dual helical cone-beam computed tomography (CT) and Katsevich-type reconstruction algorithm. Conventional cone-beam helical industrial CT imaging is based on the assumption that the entire cross-section of an object is illuminated with x-rays at each view angle. The field of view is limited by the width of planar detector. As an alternative, this paper developed a dual-helical scanning. When scanning at each helix, part of cross-section is covered by x-ray at each view angle. During reconstruction, Katsevich-type algorithm is applied, which does not rebin projection data. The algorithm is approximate, as it applies Hilbert transform on truncated projection. The reconstruction result is better than extended FDK algorithm, especially for large helical pitch.