illumination op• Data kinds: table → table
• Call: import fullseye as fs; fs.ledger.defect_contrast(light, surface='satin', slopes_deg=(2.0, 5.0, 10.0, 20.0), camera=(0.0, 0.0, 300.0), point=(0.0, 0.0), n_azimuth=12, pigment_albedo_ratio=0.5) (to call the implementation directly, import illumdesign; illumdesign.defect_contrast(light, surface='satin', slopes_deg=(2.0, 5.0, 10.0, 20.0), camera=(0.0, 0.0, 300.0), point=(0.0, 0.0), n_azimuth=12, pigment_albedo_ratio=0.5); from the registry, opsoptics.get("defect_contrast"))
Contrast of topographic and pigment defects under a light (table).
For each facet slope in *slopes_deg* the radiance toward *camera* of a facet tilted by that slope (azimuth swept in *n_azimuth* steps) is compared with the flat surface at *point*: contrast = (L_defect − L_flat) / (L_defect + L_flat) (Michelson, −1..1; the sign says whether the flank appears brighter or darker than the surround). Reported per slope as mean, max_abs and azimuth_of_max. pigment is the contrast of a flat patch whose albedo is *pigment_albedo_ratio* × the surround — the number specular glare dilutes. scatter is the contrast of a rough patch (a chipped edge, a pit floor, a fine scratch: micro-facets of every slope, modelled as Lambertian with reflectance F + (1 − F)ρ, the Fresnel fraction the flat surface would have sent into its specular direction now scattered) against the surround — the defect class dark-field lighting is built for, since a smooth facet only lights up when it mirrors the source into the camera while a rough patch scatters some of *any* light there, and at grazing incidence that Fresnel fraction is large. regime is "bright_field" when the flat surface returns specular light to the camera (specular ≥ diffuse radiance) and "dark_field" otherwise. *surface*: a preset (matte, satin, glossy, mirror, brushed_metal) or a dict {albedo, roughness, f0}.
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.
• mv_illumination_practice — Lighting in practice — wavelength, polarisation, drive modes, ambient light, safety
• 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.
• illumination_design_demo — py -3.11 examples/illumination_design_demo.py
table as input)abcd_matrix · wavefront_stats · sfr_from_edge · paraxial_trace · seidel_coefficients · spot_stats · tolerance_analysis · wavefront_from_opd
illumination)light_source · irradiance_map · illumination_uniformity · lighting_sweep · illumination_design
*Provenance: illumdesign.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.