fly_egomotion_from_flow — FLYVISION selfmotion op

• Datenarten: matrix × table → table

• Aufruf: import fullseye as fs; fs.ledger.fly_egomotion_from_flow(flow, lattice, axes=None, weights=None) (die Implementierung direkt: import flyvision; flyvision.fly_egomotion_from_flow(flow, lattice, axes=None, weights=None); aus dem Register: opsflyvision.get("fly_egomotion_from_flow"))

Verwendung

> Für diesen Operator gibt es noch keine Übersetzung. Es folgt der Originaltext unverändert.

Least-squares rotation of the eye from its flow field — and how badly the

eye's own shape conditions the answer.

Given the flow `f_i at known viewing directions d_i`, a pure rotation

`w predicts f_i = -(w x d_i)`, which is linear in w: projecting on

the tangent basis gives `f_az = -w . (d x e_az)` and

`f_el = -w . (d x e_el), so the estimate is one 2n x 3` least-squares

solve with no iteration and no starting guess (Franz et al.'s linear

egomotion estimate, *Biol. Cybern.* 2004).

The catch is not the algebra, it is the eye. A single patch of ommatidia sees

a small piece of the sphere, and over a small piece the flow of a yaw and the

flow of a sideways translation — or of a pitch — look nearly the same. This

op therefore returns the condition number of that solve next to the

answer, so that "the fit converged" and "the fit was identifiable" stay

separate claims.

flow: `(n, 2)` azimuth/elevation components per ommatidium

(:func:fly_flow_from_directions or :func:fly_matched_filter).

lattice: the eye they were measured on.

axes: `None to solve for the full 3-D rotation, or a (k, 3)` array of

axes to restrict the fit to (`[[0, 0, 1]]` = yaw only, the well-conditioned

question a forward-looking eye can actually answer).

weights: `None or (n,)` non-negative per-ommatidium weights — a

confidence, e.g. the local contrast, or zeros to drop the rim.

Returns a dict::

{"omega_rad_s": (3,), "yaw_rad_s": float, "pitch_rad_s": float,

"roll_rad_s": float, "residual_rms": float, "flow_rms": float,

"explained": float, "condition": float, "n_ommatidia": int}

with yaw about +z (left positive), pitch about +y, roll about +x, and

`explained = 1 - residual_rms/flow_rms` (1.0 = the flow is exactly a

rotation, 0.0 = the fit explains none of it).

Ground truth: handed a :func:fly_matched_filter template scaled by a known

rate, it returns that rate to machine precision and `explained = 1`; handed

a pure translation field it returns a small rate with a low `explained`; and

the condition number of a narrow forward eye is large (the tests measure it)

while the yaw-only fit is near 1.

Raises `ValueError: a *flow* that is not (n, 2)` for this lattice,

non-finite entries, a malformed *axes* / *weights*, all-zero weights, and a

lattice with fewer ommatidia than the fit has unknowns.

Ausführlicher Anwendungsleitfaden

• Leitfaden zur Familie fly_vision

Referenzen (Beispieldaten, Literatur)

• Katalog der Beispieldaten (Download-URLs / Lizenzen) — 2-D nutzt skimage.data (BSD/Public Domain) plus synthetische Bilder, 3-D nennt Download-URLs echter Datenquellen (Stanford, PDS, …).

• Herkunft und Literatur der Operatoren — die Quellen der Forschung/Verfahren, auf denen diese Operatorfamilie beruht.

• Der kanonische Algorithmus (Autor, Jahr) und seine Anwendungen stehen im Familienleitfaden oben.

Ausführbare Beispiele (verifizierte Samples, die diesen Operator wirklich aufrufen)

• poc_fly_optomotor_steering — py -3.11 examples/poc_fly_optomotor_steering.py

Typkompatible Folge-Operatoren (nehmen table als Eingabe)

fly_t4t5_field · fly_flow_from_directions · fly_matched_filter · fly_eye_merge · fly_hex_resample · fly_hs_readout

Gleiche Kategorie (selfmotion)

fly_matched_filter · fly_eye_merge


*Provenance: flyvision.py — FLYVISION Operator-Registry. Diese Notiz wird von tools/opdocs.py md erzeugt (nicht von Hand bearbeiten).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.