artifact op• Data kinds: sinogram → sinogram
• Call: import fullseye as fs; fs.ledger.ring_artifact_apply(sinogram, gain_sigma=0.02, seed=0, offsets=None) (implementation को सीधे call करना हो तो import tomography; tomography.ring_artifact_apply(sinogram, gain_sigma=0.02, seed=0, offsets=None), registry से लेना हो तो opstomography.get("ring_artifact_apply"))
detector को हर bin का gain error देता है — ring artefact का स्रोत।
> नीचे का विस्तृत विवरण मूल text में है — सारांश और headings का अनुवाद हो चुका है।
A detector bin whose gain is g reports I = g I_true, so after the logarithm the line integral picks up a constant offset -ln g at that bin, the same at every angle. Back-projecting a constant column smears it around the rotation axis, and the reconstruction grows a ring at the radius that bin's rays are tangent to. One bad pixel, one perfect circle.
The offsets are drawn once from N(0, gain_sigma) with a fixed *seed* and applied to every row, because the whole point is that the error does not vary with angle — that is what distinguishes a ring from noise, and what makes ring_artifact_remove possible.
:param sinogram: (n_angles, n_detectors). :param gain_sigma: standard deviation of the per-bin offset, >= 0. :param seed: RNG seed; there is no None (determinism is a contract here). :param offsets: explicit (n_detectors,) offsets; overrides the random draw. :returns: (n_angles, n_detectors) float64 sinogram. :raises ValueError: on a negative sigma, a non-int seed, or an *offsets* whose
length is not the detector count.
• Sample data catalog (DL URL / license) — 2-D के लिए skimage.data (BSD/public) + synthetic, 3-D के लिए real data sources (Stanford/PDS आदि) के DL URL।
• Operators का स्रोत और संदर्भ — इस op family के मूल research/methods के स्रोत।
• Algorithm का मानक स्रोत (लेखक, वर्ष) और उपयोग ऊपर की family usage guide में दिए गए हैं।
• ct_reconstruction — py -3.11 examples/ct_reconstruction.py
• poc_battery_ct_degradation — py -3.11 examples/poc_battery_ct_degradation.py
sinogram को input के रूप में लेते हैं)backproject_sinogram · filtered_backprojection · sart_reconstruct · beam_hardening_apply · beam_hardening_correct · ring_artifact_remove · metal_trace_interpolate · sinogram_center_of_rotation
artifact)beam_hardening_apply · beam_hardening_correct · ring_artifact_remove · metal_trace_interpolate
*Provenance: tomography.py — TOMOGRAPHY operator registry. यह per-op note tools/opdocs.py md से अपने-आप generate होता है (हाथ से edit न करें)।*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.