irradiance_map — OPTICS illumination op

Data kinds: tableimage2d

Call: import illumdesign; illumdesign.irradiance_map(light, size_mm=(50.0, 50.0), shape=(128, 128), height=None, z_mm=0.0, facing='up') (or opsoptics.get("irradiance_map"))

Usage

Irradiance on the part plane (`image2d`, units of intensity / mm²).

The plane is centred on the axis, *size_mm* = (height, width) in mm sampled

on *shape* = (rows, cols); +y is up (row 0 is the top). *height* (optional,

same shape as the map, mm) tilts each pixel's normal to that of a relief

surface — a dent or a bump then shows as the irradiance it actually

receives. *z_mm* shifts the plane (a thick part's top face). *facing*

`"up" (+z, toward the camera) or "down"` — the face a backlight

illuminates (what the camera sees through the part's apertures).

Closed forms: an isotropic point source (`cos_exponent=0`) at height h

gives `E = I0 cos³θ / h²; a Lambertian emitter (cos_exponent=1`)

pointing down gives the cos⁴ law `E = I0 cos⁴θ / h²`.

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)

mv_illumination_practice — 照明の実務知識 — 波長・偏光・点灯方式・外光・安全

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)

illumination_design_demopy -3.11 examples/illumination_design_demo.py

Ops the type connects to (they accept image2d as input)

fraunhofer_pattern · psf_to_mtf · illumination_uniformity · render_through_lens · surface_defect · defocus_blur

Same category (illumination)

light_source · illumination_uniformity · defect_contrast · 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.