depth oplightfield → image2dimport fullseye as fs; fs.ledger.lf_epi_slope(lf, *, window=9, min_energy=1e-10) (実装を直接呼ぶなら import lightfield; lightfield.lf_epi_slope(lf, *, window=9, min_energy=1e-10)、台帳から引くなら opslightfield.get("lf_epi_slope"))fullseye.ledger.lf_epi_slope(...) は宣言 out 型 image2d の値だけを返す(本体は補助情報も返す)。捨てられた側が要るときは fullseye.ledger.lf_epi_slope.raw(...)、または lightfield.lf_epi_slope を直接呼ぶ。Per-pixel slope from the EPI line orientation (structure tensor, one pass).
A scene point traces a straight line in the epipolar-plane image
(:func:lf_epi), so along that line the intensity is constant:
E_u + s * E_x = 0. Accumulating that constraint over the whole angular
grid and a window x window spatial neighbourhood gives the closed-form
least-squares slope s = -(J_ux + J_vy) / (J_xx + J_yy) with
J_ab = sum(E_a * E_b) — one pass over the light field, no sweep, both
the horizontal and vertical EPI directions pooled.
This estimator is biased, and the bias is the reason to also run
:func:lf_depth_from_focus. It is ordinary (not total) least squares on
finite differences, so it needs the EPI line to advance less than roughly
one texture correlation length per view. Measured 2026-09-01 on
5x5x64x64 synthetic fields, median over the interior: with texture
sigma = 1.5 px, true +1.00 -> +1.0004, +0.50 -> +0.5285,
+1.50 -> +1.3018, +2.00 -> +1.4614; with sigma = 5.0 px the same
slopes give +1.0003, +0.5029, +1.4827, +1.9482. Integer
slopes on a wrapped field come back within 4e-4 and s = 0 is exact;
|s| > 1 is under-estimated, by 27% at s = 2 on the roughest texture.
Use it as a fast dense initialiser, not as the final word.
Returns (slope_map, energy): the (H, W) slope map and the (H, W)
gradient energy J_xx + J_yy that was the denominator. Pixels whose
energy is below min_energy have no measurable parallax (a flat patch
of sky); their slope is set to 0 and their energy reported as-is, so you
threshold on energy instead of being handed a plausible-looking number
divided by ~0.
Raises ValueError: lf not a valid light field, an angular/spatial
shape where neither EPI direction carries information (the horizontal EPI
needs U >= 2 and W >= 2, the vertical needs V >= 2 and
H >= 2), an even or non-positive window, a non-positive min_energy.
py -3.11 examples/lightfield_depth.pypy -3.11 examples/poc_lightfield_depth.pyimage2d を入力に取れる)lf_from_mla · lf_disparity_to_depth · lf_all_in_focus
depth)lf_depth_from_focus · lf_disparity_to_depth · lf_all_in_focus · lf_plenoptic_design
Provenance: lightfield.py — LIGHTFIELD 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.