lamina op• Data kinds: matrix → matrix
• Call: import fullseye as fs; fs.ledger.fly_onoff_split(movie, dt_s, tau_on_s=0.02, tau_off_s=0.02, rectify=True) (to call the implementation directly, import flyvision; flyvision.fly_onoff_split(movie, dt_s, tau_on_s=0.02, tau_off_s=0.02, rectify=True); from the registry, opsflyvision.get("fly_onoff_split"))
Split a contrast movie into the ON and OFF channels the medulla carries.
Beyond the lamina the fly stops carrying one signed signal and carries two:
an ON channel (Mi1 / Tm3, brightening) and an OFF channel (Tm1 / Tm2, darkening), each with its own relay dynamics. This op is that split, and it keeps the rectification *optional* on purpose: the split was measured downstream, in the motion response (Joesch et al., *Nature* 468:300, 2010), while L1/L2 themselves respond linearly (Clark et al., *Neuron* 70:1165, 2011), so a pathway that rectifies at the lamina is making a claim the recordings do not.
movie: (T, n) contrast, rows = time (the return of fly_lamina_filter). dt_s: sample interval, seconds. tau_on_s / tau_off_s: the low-pass time constant of each channel, seconds.
rectify: True half-wave rectifies (ON = max(c, 0), OFF = max(-c, 0), both >= 0); False passes the signed contrast into the ON channel and its negation into the OFF channel, which is the linear L1/L2 case and lets the rectification happen downstream instead.
Returns (T, 2n) float64: columns 0..n-1 are ON, n..2n-1 are OFF, the same ommatidium order in each half.
Ground truth (exact, with tau_on_s == tau_off_s so the two channels share one filter):
• ON - OFF is the low-passed input, whichever *rectify* you chose;
• with rectify=True, ON + OFF is the low-passed absolute value;
• a movie that never goes negative leaves the OFF channel identically zero (and vice versa) — the split does not invent a dark event.
Raises ValueError: a non-2-D / too-short / non-finite *movie*, a movie
over MAX_MOVIE_ELEMENTS, and a non-positive *dt_s* / *tau_on_s* / *tau_off_s*.
• 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.
• poc_fly_optomotor_steering — py -3.11 examples/poc_fly_optomotor_steering.py
matrix as input)fly_lamina_filter · fly_t4t5_field · fly_flow_from_directions · fly_egomotion_from_flow · fly_hs_readout
lamina)*Provenance: flyvision.py — FLYVISION 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.