motion op• Data kinds: video → pairs
• Call: import quatimage; quatimage.riesz_displacement_series(video, f_lo, f_hi, fps, scales: 'int' = 4) -> 'np.ndarray' (or opsquat.get("riesz_displacement_series"))
Whole-frame displacement waveform from the monogenic phase. → (T, 2).
The contrast-weighted spatial mean of :func:riesz_displacement: the
rigid-body motion of the scene in pixels, one `(dx, dy)` row per frame.
The `(n, 2) layout is the shared 1-D convention (dsp.spectrum`,
`funct1d, opsoptics`'s MTF curves), so the trace can be handed to
`dsp.spectrum` to read off a resonant frequency without any repacking.
Weights are the `|z|^2` contrast the field solve uses, restricted to the
pixels marked `valid`, so blank regions do not drag the average towards
zero. A clip with no valid pixel anywhere (a constant image) returns exact
zeros rather than dividing by zero.
Accuracy, the `J0` cliff and the multi-orientation failure all inherit from
:func:riesz_displacement — read its head-to-head table before trusting a
number from here. On a single-grating 64x64x64 / 8 px / 4 Hz clip a true
0.5 px amplitude is recovered as 0.50000000000000 px (2.2e-16 relative);
on the two-grating `motionmag.synthesize_translation` default the same
0.5 px comes back 13.0 % low, with nothing to signal it.
• quaternion_monogenic family guide
• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).
• Operator provenance and references — the sources of the research/methods this op family came from.
• The canonical algorithm (author, year) and its uses are named in the family usage guide above.
• quaternion_monogenic — py -3.11 examples/quaternion_monogenic.py
pairs as input)—
motion)riesz_motion_magnify · riesz_displacement
*Provenance: quatimage.py — QUAT operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.