geometry op• 資料種類:sinogram → sinogram
• 呼叫: import fullseye as fs; fs.ledger.sinogram_center_shift(sinogram, shift_px=None, angles_deg=None)(要直接呼叫實作,import tomography; tomography.sinogram_center_shift(sinogram, shift_px=None, angles_deg=None);從台帳取用則 opstomography.get("sinogram_center_shift"))
把正弦圖重新對中到它的旋轉軸上。
> 以下的詳細說明為原文 —— 摘要與標題已翻譯。
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.
• 範例資料目錄(下載 URL / 授權) —— 2-D 用 skimage.data(BSD/公有領域)加合成圖,3-D 給出真實資料源(Stanford/PDS 等)的下載 URL。
• 運算子來歷與參考文獻 —— 該運算子族所依據的研究/方法出處。
• 演算法的正典(作者、年份)與用途見上面的族使用指南。
• ct_reconstruction — py -3.11 examples/ct_reconstruction.py
sinogram 作為輸入)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 運算子登記表。本條目由 tools/opdocs.py md 自動產生(請勿手動編輯)。*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.