appearance op• Data kinds: signal → vector
• Call: import matappear; matappear.spectrum_to_srgb(nm, reflectance, illuminant=None) -> 'np.ndarray' (or opsoptics.get("spectrum_to_srgb"))
Spectral reflectance → linear sRGB (before gamma). Normalised so a white surface (reflectance 1) becomes (1,1,1).
> The detailed description below is the original text — the summary and the headings are translated.
nm: 波長格子 (K,) [nm]。単調増加。
reflectance: (..., K) の分光反射率(0–1 想定、範囲外でも計算は通る)。
illuminant: (K,) の光源分光分布。既定は D65 の平滑近似。
返り値: (..., 3) の線形 sRGB。負の値はクリップしない — 色域外は負で返るのが正直で、
クリップしたい呼び手が明示的にやる(黙って丸めると「表現できない色」が見えなくなる)。
正規化: 反射率 1 の完全拡散面が sRGB の基準白 D65 に落ちるよう、同じ光源・同じ格子で
計算した白の XYZ で成分ごとに割る(von Kries 型の白色順応の最小形)。実測で
反射率 1 → (1.000000, 1.000000, 0.999999)、0.5 → 0.5。したがって**絶対輝度ではなく
相対値**であり、レンダラの露出に掛ける使い方を想定している。
Every optics op validates its input before computing (nothing slips through silently):
• Units are baked into the argument name — _mm / _um / _deg / _mrad. Confusing mm with µm does not crash; it yields a plausible-looking wrong answer, so the name prevents it. Nothing here guesses the unit from the magnitude.
• **Strings raise ValueError** — float('50') succeeds, so an unparsed configuration value would slip through as a length (measured: thin_lens('50', '200') returned a plausible 66.667 mm). bool is refused too, as the implicit promotion True == 1.
• **complex / masked arrays raise ValueError (real-valued slots only; silently dropping the imaginary part or peeling off the mask is refused). NaN/Inf raises ValueError on every input.**
• Division by zero and its relatives are refused by name: focal length 0, radius of curvature 0, refractive index <= 0, a fully opaque aperture (all zeros, so the normalisation is 0/0), a PSF whose sum is <= 0, a Stokes vector with S0 = 0, and an object sitting at the front focal point (the image is at infinity).
• Only two ops return a non-finite value, and both state it as a contract: depth_of_field returns far_mm = inf beyond the hyperfocal distance (that is what the hyperfocal distance means), and gaussian_beam returns wavefront_radius_mm = inf at the waist (the radius of curvature of a plane wavefront). Both also return a finite companion (far_is_infinite / curvature_per_mm). **Any other silent NaN/Inf is detected internally and raises ValueError** — "float64 overflowed" and "the answer is infinite" are different claims, so the first is never returned wearing the face of the second.
• Size caps: generated grids are capped by optics.MAX_GRID (4096); supplied fields/PSFs/apertures by optics.MAX_FIELD_ELEMENTS (2^24); ABCD element chains by optics.MAX_SYSTEM_ELEMENTS (1024); Zernike by MAX_ZERNIKE_TERMS (512) / MAX_ZERNIKE_ORDER (40) / MAX_ZERNIKE_BASIS (2^25). This closes, fail-closed, the paths where a small argument triggers a huge internal allocation (measured: n_max=40 × 4096² needs 108 GB).
• Physically impossible states are refused too: a Stokes vector with degree of polarisation > 1, negative transmittance, negative intensity, and invalid Zernike indices such as n-|m| odd.
• colorimetry — 測色と分光の知識 — 色は「分光 × 光源 × 観測者」でしか決まらない
• mv_illumination_practice — 照明の実務知識 — 波長・偏光・点灯方式・外光・安全
• 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.
• appearance_structural_colour — py -3.11 examples/appearance_structural_colour.py
vector as input)—
appearance)cie_xyz_from_wavelength · thin_film_reflectance · grating_wavelengths · grating_rgb · thin_film_rgb · ward_anisotropic
*Provenance: matappear.py — OPTICS operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.