dichromatic op• 資料種類:rgbimage × labels → vector
• 呼叫: import fullseye as fs; fs.ledger.illuminant_from_dichromatic_planes(image_rgb, labels, min_pixels=16, min_plane_ratio=1e-06, min_intersection_ratio=1e-06)(要直接呼叫實作,import specularity; specularity.illuminant_from_dichromatic_planes(image_rgb, labels, min_pixels=16, min_plane_ratio=1e-06, min_intersection_ratio=1e-06);從台帳取用則 opsspecular.get("illuminant_from_dichromatic_planes"))
由兩種以上材質恢復光源顏色。→ 單位 3 向量。
> 以下的詳細說明為原文 —— 摘要與標題已翻譯。
Lee's construction (1986). Under the dichromatic model every pixel of one material lies in the plane spanned by that material's body colour and the illuminant colour, so each material contributes a plane through the origin of RGB, and all of those planes contain the illuminant direction. Two materials with different body colours therefore intersect in exactly one line, and that line is the answer — a null-space computation, closed form.
*labels* is an (H, W) integer map naming the material at each pixel; negative labels are ignored (background). Each material needs *min_pixels* pixels and genuine highlight variation: a material seen with no specular reflection at all has colours along a single ray, which defines no plane. That is measured by the second-to-first singular ratio of its colour matrix and rejected below *min_plane_ratio* rather than contributing an arbitrary normal.
The returned direction is unit length with a positive component sum (illuminant colours are positive; the null space fixes the line, not the sign). On synthetic data with three known materials it reproduces the true illuminant with a maximum component error of 4.4e-14 and an angular error that rounds to 0.0 degrees (measured in tests/test_specularity.py).
*min_intersection_ratio* guards the answer itself: if the plane normals are nearly parallel — two materials whose body colours differ only in brightness, which is the same material twice — the intersection is ill-conditioned and the call raises instead of returning a direction picked by rounding error.
Raises ValueError: shape or dtype problems as in specular_diffuse_split; *labels* is not an (H, W) integer map matching the image; more than MAX_MATERIALS distinct labels; fewer than two materials survive the *min_pixels* and *min_plane_ratio* tests; the surviving planes do not intersect in a well-determined line.
• 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。
• poc_white_balance — py -3.11 examples/poc_white_balance.py
• specular_photometric — py -3.11 examples/specular_photometric.py
vector 作為輸入)—
dichromatic)specular_diffuse_split · specular_coefficient_map · specular_free_transform
*Provenance: specularity.py — SPECULAR 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.