fourier opqimage → qimageimport fullseye as fs; fs.ledger.iqft2(spectrum, side, mu=None) -> 'np.ndarray' (実装を直接呼ぶなら import quatimage; quatimage.iqft2(spectrum, side, mu=None) -> 'np.ndarray'、台帳から引くなら opsquat.get("iqft2"))Inverse quaternion Fourier transform of a centred spectrum. → (H, W, 4).
The exact inverse of :func: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.
py -3.11 examples/quaternion_monogenic.pyqimage を入力に取れる)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 operator registry. この per-op ノートは tools/opdocs.py md が自動生成(手編集しない)。
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.