fullseye

fly_lgmd_eta — FLYVISION looming op

• データ種: signal → signal
• 呼び出し: import fullseye as fs; fs.ledger.fly_lgmd_eta(theta_signal, dt_s, alpha=4.7, delay_s=0.0) (実装を直接呼ぶなら import flyvision; flyvision.fly_lgmd_eta(theta_signal, dt_s, alpha=4.7, delay_s=0.0)、台帳から引くなら opsflyvision.get("fly_lgmd_eta"))

使い方

LGMD/eta looming response from an expanding subtended angle.

The multiplicative looming model::

eta(t) = theta'(t - delay) * exp(-alpha * theta(t - delay))

where theta_signal is the object’s full subtended angle over time, in radians. The product of the angular expansion rate and an exponentially decaying gain gives a response that peaks a fixed time before collision.

theta_signal: the full subtended angle per sample, radians. dt_s: the sample interval, seconds. alpha: the gain-decay constant. delay_s: a fixed neural delay, seconds.

Returns a 1-D float64 array eta(t) of the same length.

Ground truth: for an object of half-size l approaching at speed |v|, eta peaks at a time-to-contact of alpha*l/|v| - delay_s (Gabbiani et al. Eq. 5), where the subtended angle is exactly 2*atan(1/alpha) (Eq. 6; 24.0 degrees for alpha = 4.7) — both pinned in the tests.

Raises ValueError: a non-1-D / empty / too-short (< 3) / non-finite theta_signal, a signal over :data:MAX_SIGNAL_POINTS, a non-positive dt_s / alpha, and a negative delay_s.

参考(サンプルデータ・文献)

• サンプルデータ カタログ(DL URL / ライセンス) — 2-D は skimage.data(BSD/public)+ 合成、3-D は実データ源(Stanford/PDS 等)の DL URL。
• 演算子の来歴・参考文献 — この op 族の元になった研究/手法の出典。
• アルゴリズムの正典(著者・年)と用途は上記ファミリ使い方ガイドに記載。

実行できる例(この op を実際に呼ぶ検証済みサンプル)

• poc_fly_vision — py -3.11 examples/poc_fly_vision.py

型が繋がる次の op(signal を入力に取れる)

fly_emd_response · fly_tau_from_expansion · fly_dsi

同カテゴリ(looming)

fly_tau_from_expansion

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Provenance: flyvision.py — FLYVISION 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.

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