fourier op• 数据种类:qimage → qimage
• 调用: import fullseye as fs; fs.ledger.iqft2(spectrum, side, mu=None) -> 'np.ndarray'(要直接调用实现,import quatimage; quatimage.iqft2(spectrum, side, mu=None) -> 'np.ndarray';从台账取用则 opsquat.get("iqft2"))
中心化频谱的逆四元数傅里叶变换。→ (H, W, 4)。
> 以下的详细说明为原文 —— 摘要与标题已翻译。
The exact inverse of qft2 for the same side and the same mu:
measured round-trip error 2.22e-15 for both sides on a standard-normal (32, 32, 4) field. The kernel is exp(+mu * 2*pi*(...)) applied on the side named, and the 1/(H*W) normalisation is carried here, as in numpy.fft.ifft2.
Using the wrong side does not raise. iqft2(qft2(q, "left"), "right") returns a finite, plausible quaternion image that is simply not q:
measured max|err| = 1.113 on a random colour image whose own range is 0.9994 (another seed: 1.063 against 1.0), and — the dangerous case — only 0.054 against a range of 1.076 on a grey-axis-dominated one, which is small enough to survive a look at the picture. The side argument is required at both ends for exactly this reason, and the two calls must agree: nothing in the data records which transform produced it, so nothing downstream can catch the mismatch for you.
Raises ValueError: *spectrum* is not a valid (H, W, 4) field; *side* is not 'left' / 'right'; *mu* is not a finite non-zero 3-vector.
• 示例数据目录(下载 URL / 许可证) —— 2-D 用 skimage.data(BSD/公有领域)加合成图,3-D 给出真实数据源(Stanford/PDS 等)的下载 URL。
• 算子来历与参考文献 —— 该算子族所依据的研究/方法出处。
• 算法的正典(作者、年份)与用途见上面的族使用指南。
• quaternion_monogenic — py -3.11 examples/quaternion_monogenic.py
qimage 作为输入)quaternion_to_rgb · quat_norm · quat_conjugate_image · quat_normalize_image · quat_image_multiply · monogenic_amplitude · monogenic_phase · monogenic_orientation
fourier)*Provenance: quatimage.py — QUAT 算子登记表。本条目由 tools/opdocs.py md 自动生成(请勿手工编辑)。*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.