flow_magnitude — REPRCONV flow op

• Data kinds: flow_dense → voxel

• Call: import fullseye as fs; fs.ledger.flow_magnitude(flow) (to call the implementation directly, import reprconv; reprconv.flow_magnitude(flow); from the registry, opsreprconv.get("flow_magnitude"))

Usage

Dense scene flow (3,D,H,W) → a speed volume voxel (D,H,W). The exit from flow.

sqrt(dz^2 + dy^2 + dx^2). One-way (the direction is discarded, so it cannot be inverted). What is discarded can be stated explicitly: of the 3 components, the direction worth 2 degrees of freedom disappears, and only the magnitude remains. To see the direction as well, use flow_to_rgbimage.

Args:

flow: (3, D, H, W). Component order is (dz, dy, dx) (the scene_flow_lk convention).

Returns:

(D, H, W) float64.

Raises:

ValueError: not a dense flow / non-finite.

References (sample data, literature)

• 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.

Runnable examples (verified samples that actually call this op)

• perception_on_video — py -3.11 examples/perception_on_video.py

• representation_roundtrip — py -3.11 examples/representation_roundtrip.py

Ops the type connects to (they accept voxel as input)

correlation_score

Same category (flow)

flow_to_rgbimage · flow_speed · flow_apply


*Provenance: reprconv.py — REPRCONV 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.