light_spec — OPTICS scene op

• Data kinds: none → table (an op determined by its arguments alone — it takes no image or data input)

• Call: import fullseye as fs; fs.ledger.light_spec(kind: 'str' = 'coaxial', source: 'str' = 'led', wavelength_nm: 'float' = 550.0, bandwidth_nm: 'float' = 30.0, radius_mm: 'float' = 40.0, height_mm: 'float' = 110.0, size_mm: 'float' = None, n: 'int' = 196, intensity: 'float' = 1.0, cos_exponent: 'float' = 1.0, polarization: 'str' = None, model: 'str' = None, maker: 'str' = None) -> 'dict' (to call the implementation directly, import optscene; optscene.light_spec(kind: 'str' = 'coaxial', source: 'str' = 'led', wavelength_nm: 'float' = 550.0, bandwidth_nm: 'float' = 30.0, radius_mm: 'float' = 40.0, height_mm: 'float' = 110.0, size_mm: 'float' = None, n: 'int' = 196, intensity: 'float' = 1.0, cos_exponent: 'float' = 1.0, polarization: 'str' = None, model: 'str' = None, maker: 'str' = None) -> 'dict'; from the registry, opsoptics.get("light_spec"))

Usage

A light's specification. The geometry is left to illumdesign.light_source; the properties of the light are added here.

kind is coaxial / ring / dome / bar / backlight (shape of the fixture). source is led / halogen / laser, and it changes the meaning of wavelength_nm and bandwidth_nm ―― LED is narrowband (~30 nm), halogen broadband (~300 nm), laser single-wavelength (0 nm) and coherent. The specular fraction of roughness exp(-(4πσcosθ/λ)²) depends on wavelength, so the same surface looks different depending on the light source.

size_mm is the physical span of the fixture. Whether it shows up as a mirror image = the essence of bright field / dark field, so with a point approximation dark field cannot work in principle. If omitted, half of radius_mm is used.

Family-wide input contract (fail-closed)

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.

Detailed usage guide

• optics_imaging family guide

Background guides (the physics and conventions behind this op)

• dataset_conventions — Training-dataset conventions — COCO / YOLO / VOC and pitfalls in visual inspection

• mv_cameras — Industrial camera makers (sensor mapping, line scan / TDI)

• mv_illumination_practice — Lighting in practice — wavelength, polarisation, drive modes, ambient light, safety

• mv_image_sensors — Industrial image sensors (mainly current products)

• virtual_machine_vision — Virtual machine vision — enumerating the parameters and an object model

References (sample data, literature)

• 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.

Runnable examples (verified samples that actually call this op)

• studio_raytrace_scene — py -3.11 examples/studio_raytrace_scene.py

• vision_layout_from_catalog — py -3.11 examples/vision_layout_from_catalog.py

Ops the type connects to (they accept table as input)

abcd_matrix · wavefront_stats · sfr_from_edge · paraxial_trace · seidel_coefficients · spot_stats · tolerance_analysis · wavefront_from_opd

Same category (scene)

scene_material · scene_plane · scene_sphere · scene_box · scene_cylinder · surface_defect · surface_finish · random_defects


*Provenance: optscene.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.