fly_hex_resample — FLYVISION `sample` op

• Data kinds: image2d × table → signal

• Call: import fullseye as fs; fs.ledger.fly_hex_resample(image2d, lattice, drho_deg=8.23, fov_deg=90.0, mode='pinhole') (to call the implementation directly, import flyvision; flyvision.fly_hex_resample(image2d, lattice, drho_deg=8.23, fov_deg=90.0, mode='pinhole'); from the registry, opsflyvision.get("fly_hex_resample"))

Usage

Resample a pinhole image onto an ommatidial lattice (the eye's view).

Each ommatidium integrates the image under a Gaussian acceptance function of

full width at half maximum *drho_deg* weighted by the pixel solid angle::

signal_i = sum_p w_ip * image_p / sum_p w_ip

w_ip = exp(-4 ln2 * a_ip^2 / drho_deg^2) * (1 + X_p^2 + Y_p^2)^(-3/2)

with `a_ip` the angular distance between ommatidium *i* and pixel *p*, cut

off at `a <= 2*drho_deg, and X, Y` the pinhole-normalised pixel

coordinates. The image is a perspective (pinhole) view whose optical axis is

the lattice centre and whose *fov_deg* is the full vertical field of view.

image2d: a 2-D `(H, W)` pinhole image.

lattice: the dict returned by :func:fly_hex_lattice.

drho_deg: the acceptance FWHM in degrees.

fov_deg: the full vertical field of view in degrees.

mode: `"pinhole"` (the only projection implemented).

Returns a 1-D float64 signal of `n` ommatidial intensities.

Ground truth: an azimuthal sinusoid of angular wavelength `lambda` is

sampled with its amplitude scaled by the analytic modulation transfer

`exp(-pi^2 drho_deg^2 nu^2 / (4 ln2)), nu = 1/lambda`, to within 0.05

over `lambda` from 15 to 80 degrees at equatorial ommatidia (pinned in the

tests).

Raises `ValueError`: a non-2-D / empty / non-finite *image2d*, an image

over the element cap, a *lattice* that is not a :func:fly_hex_lattice result,

a non-positive *drho_deg* / *fov_deg*, a *fov_deg* not below 180, an unknown

*mode*, a `n_ommatidia * n_pixels product over :data:MAX_RESAMPLE_ELEMENTS`,

and — this is the field-of-view guard — any ommatidium whose nearest pixel is

farther than `dphi_rad/2` away (the eye is looking outside the image).

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_vision — py -3.11 examples/poc_fly_vision.py

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

fly_emd_response · fly_lgmd_eta · fly_tau_from_expansion · fly_dsi

Same category (`sample`)

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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_resample — FLYVISION sample op