design op• Data kinds: table → image2d
• Call: import raytrace; raytrace.opd_map(system, field=None, size=64, wavelength_um=None, image_mm=None, fill=0.0) (or opsoptics.get("opd_map"))
Optical path difference over the exit pupil, in waves (`image2d`).
The OPD of each ray is the chief ray's optical path from a common object-space
wavefront to the exit-pupil reference sphere (centred on the chief
ray's image point, passing through the paraxial exit pupil on axis) minus
the ray's own, divided by the wavelength (Welford's sign: an undercorrected
spherical singlet gives `W = +W040·ρ⁴ with W040 = S_I/8). The map is sampled on a size × size` grid over
the unit pupil (row = +y down the array, column = +x); points outside the
pupil or vignetted are set to *fill* (default 0 so the array is finite —
pass `fill=np.nan` to see the pupil boundary). The pupil mask is available
from :func:opd_samples.
Feed the map to `match3d.fit_zernike` (coefficients in waves) and then to
`optics.wavefront_stats` for RMS / PV / Strehl. On a stigmatic system
(an on-axis paraboloid mirror) the map is zero to machine precision; a pure
image-plane defocus produces the textbook `W020·ρ²`; for a spherical
singlet the Zernike (4,0) term reproduces the Seidel `S_I/8` at small
aperture (all tested).
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.
• 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.
• lens_design_demo — py -3.11 examples/lens_design_demo.py
image2d as input)fraunhofer_pattern · psf_to_mtf · illumination_uniformity · render_through_lens · surface_defect · defocus_blur
design)lens_system · thick_lens · glass · example_system · glass_catalog · sellmeier · paraxial_trace · seidel_coefficients
*Provenance: raytrace.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.