fly_hex_lattice — FLYVISION `lattice` op

• Data kinds: none → table (an op determined by its arguments alone — it takes no image or data input)

• Call: import fullseye as fs; fs.ledger.fly_hex_lattice(radius=15, dphi_deg=4.63, az0_deg=0.0, el0_deg=0.0, geometry='regular') (to call the implementation directly, import flyvision; flyvision.fly_hex_lattice(radius=15, dphi_deg=4.63, az0_deg=0.0, el0_deg=0.0, geometry='regular'); from the registry, opsflyvision.get("fly_hex_lattice"))

Usage

Hexagonal ommatidial lattice: viewing directions of a compound eye.

A hexagon of n = 3*radius*(radius+1)+1 ommatidia on axial coordinates (u, v) with -radius <= u <= radius and max(-radius, -radius-u) <= v <= min(radius, radius-u) (u outer, v inner), each given an azimuth, an elevation and a unit viewing direction in body coordinates (x forward, y left, z up; az = atan2(y, x) left positive, el = asin(z)).

geometry="regular": az = az0 + dphi*(v + u/2), el = el0 + dphi*(sqrt(3)/2)*u — an isotropic hexagon.

geometry="boxeye": the pixel-grid distortion of the connectome-derived

models, pixel (y, x) = (13*(u + v/2), 13*v) with 13 px = dphi, so az = az0 - v*dphi and el = el0 - (u + v/2)*dphi; the diagonal neighbour is 1.118x the axial spacing.

radius: the hexagon radius in ommatidia.

dphi_deg: the inter-ommatidial angle in degrees. az0_deg / el0_deg: the direction of the lattice centre (the optical axis).

geometry: one of GEOMETRIES.

Returns a dict {"uv": (n,2) int, "az_rad": (n,), "el_rad": (n,), "dirs": (n,3) unit vectors, "dphi_rad": float, "geometry": str}.

Ground truth: n == 3*radius*(radius+1)+1 exactly, every dirs row is a unit vector, and for "boxeye" the ratio of the diagonal to the axial nearest-neighbour angular spacing is 1.118 (both pinned in the tests).

Raises ValueError: a *radius* outside [1, MAX_LATTICE_RADIUS], a non-positive *dphi_deg*, a non-real / non-finite / string / bool angle, and an unknown *geometry*.

Detailed usage guide

• fly_vision family guide

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)

• poc_fly_optomotor_steering — py -3.11 examples/poc_fly_optomotor_steering.py

• poc_fly_vision — py -3.11 examples/poc_fly_vision.py

• poc_print_registration — py -3.11 examples/poc_print_registration.py

Ops the type connects to (they accept `table` as input)

fly_t4t5_field · fly_flow_from_directions · fly_matched_filter · fly_egomotion_from_flow · fly_eye_merge · fly_hex_resample · fly_hs_readout

Same category (`lattice`)

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*Provenance: flyvision.py — FLYVISION operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

fly_hex_lattice — FLYVISION lattice op