sinogram_center_shift — TOMOGRAPHY geometry op

• 資料種類:sinogram → sinogram

• 呼叫:import tomography; tomography.sinogram_center_shift(sinogram, shift_px=None, angles_deg=None)(或 opstomography.get("sinogram_center_shift"))

用法

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

:func: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 :func: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.

參考(範例資料・文獻)

• 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。

可執行的範例(實際呼叫該運算子並已驗證的樣例)

• ct_reconstruction — py -3.11 examples/ct_reconstruction.py

型別可銜接的下一個運算子(可接受 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

同類別(geometry)

sinogram_center_of_rotation

*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.