depth op• 資料種類:lightfield → image2d
• 呼叫: import fullseye as fs; fs.ledger.lf_epi_slope(lf, *, window=9, min_energy=1e-10)(要直接呼叫實作,import lightfield; lightfield.lf_epi_slope(lf, *, window=9, min_energy=1e-10);從台帳取用則 opslightfield.get("lf_epi_slope"))
• 經台帳呼叫的回傳值: fullseye.ledger.lf_epi_slope(...) 只回傳宣告的 out 型別 image2d 的值(底層函式還會回傳輔助資訊)。需要被捨棄的部分時,請用 fullseye.ledger.lf_epi_slope.raw(...),或直接呼叫 lightfield.lf_epi_slope。
由 EPI 線的方向得到逐像素斜率(結構張量,一趟完成)。
> 以下的詳細說明為原文 —— 摘要與標題已翻譯。
A scene point traces a straight line in the epipolar-plane image (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 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*.
• 範例資料目錄(下載 URL / 授權) —— 2-D 用 skimage.data(BSD/公有領域)加合成圖,3-D 給出真實資料源(Stanford/PDS 等)的下載 URL。
• 運算子來歷與參考文獻 —— 該運算子族所依據的研究/方法出處。
• 演算法的正典(作者、年份)與用途見上面的族使用指南。
• lightfield_depth — py -3.11 examples/lightfield_depth.py
• poc_lightfield_depth — py -3.11 examples/poc_lightfield_depth.py
image2d 作為輸入)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 運算子登記表。本條目由 tools/opdocs.py md 自動產生(請勿手動編輯)。*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.