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"))
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*.
• 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。
• poc_fly_vision — py -3.11 examples/poc_fly_vision.py
signal を入力に取れる)fly_emd_response · fly_tau_from_expansion · fly_dsi
looming)*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.