geometry op• Data kinds: sinogram → sinogram
• Call: import fullseye as fs; fs.ledger.sinogram_center_shift(sinogram, shift_px=None, angles_deg=None) (to call the implementation directly, import tomography; tomography.sinogram_center_shift(sinogram, shift_px=None, angles_deg=None); from the registry, opstomography.get("sinogram_center_shift"))
Re-centre a sinogram on its axis of rotation.
Shifts every projection by -shift_px along the detector axis with linear interpolation. With shift_px=None the shift is measured first by sinogram_center_of_rotation, which makes this the one-call fix.
Round-trip on the Shepp-Logan phantom, shifting by *d* and back:
d max |error| relative to the peak line integral
1.00 px 0.0e+00 0.0e+00 (an integer shift is exact)
0.50 px 1.4e-01 1.2e-01
0.25 px 1.1e-01 9.2e-02
A *fractional* shift is not a small operation and this is the operator's honest limitation: 12 % of the peak, on a phantom with sharp edges, from one round trip. Interpolation is a low-pass filter and the sinogram of an edge is not band-limited, so there is nothing to recover on the way back. Using a Fourier shift instead would trade this visible blur for invisible ringing at the detector edges, which is worse in the way that matters here. The consequence is in sinogram_center_of_rotation's table: an integer centre error is fully repairable, a half-pixel one is not.
:param sinogram: (n_angles, n_detectors). :param shift_px: axis offset in detector bins; None -> measure it. :param angles_deg: view angles, used only when *shift_px* is None. :returns: (n_angles, n_detectors) float64 sinogram. :raises ValueError: if |shift_px| is at or past half the detector width —
past that the object has been shifted out of the field of view and what
comes back is edge padding, which reconstructs as a plausible, empty slice.
• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).
• Operator provenance and references — the sources of the research/methods this op family came from.
• The canonical algorithm (author, year) and its uses are named in the family usage guide above.
• ct_reconstruction — py -3.11 examples/ct_reconstruction.py
sinogram as input)backproject_sinogram · filtered_backprojection · sart_reconstruct · beam_hardening_apply · beam_hardening_correct · ring_artifact_apply · ring_artifact_remove · metal_trace_interpolate
geometry)*Provenance: tomography.py — TOMOGRAPHY operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.