illumination 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.coaxial_illumination(reflectance=0.5, absorptance=0.0, back_reflectance=0.04, plate_thickness_mm=1.0, plate_index=1.52, panel_mm=60.0, panel_distance_mm=60.0, camera_distance_mm=200.0, field_mm=20.0, part='mirror', telecentric=False, panel_radiance=None, shape=(65, 65), n_panel=None) (to call the implementation directly, import illumdesign; illumdesign.coaxial_illumination(reflectance=0.5, absorptance=0.0, back_reflectance=0.04, plate_thickness_mm=1.0, plate_index=1.52, panel_mm=60.0, panel_distance_mm=60.0, camera_distance_mm=200.0, field_mm=20.0, part='mirror', telecentric=False, panel_radiance=None, shape=(65, 65), n_panel=None); from the registry, opsoptics.get("coaxial_illumination"))
Coaxial (half-mirror) lighting: the round-trip T*R budget and the image a camera sees (table).
The panel (square, side *panel_mm*, unfolded distance *panel_distance_mm* from the part through the 45-degree half mirror) lights the part by one reflection (R); the camera (pinhole at *camera_distance_mm*, or telecentric) looks through the mirror (T = 1 - R - A).
Budget: round_trip = R T (1/4 for the default lossless 50/50 mirror; splitter_reflectance / splitter_transmittance carry R and T under the names the optscene coaxial light reads), optimum_reflectance = (1 - A) / 2, max_round_trip = (1 - A)^2 / 4 (0.25 for a lossless mirror), ghost_ratio = T^2 r_b / R (the back-surface reflection of the plate, relative to the front reflection, on the illumination leg) and ghost_offset_mm = 2 t tan(theta_r) cos 45 deg (its lateral shift; sin theta_r = sin 45 / n).
Image (camera view, *shape* pixels over a square field of half-width *field_mm*):
• part="mirror": a specular part shows the panel itself, so the image is R T L(panel point) with the panel point x (1 + h_panel / h_camera) (x for a telecentric lens) — the panel's non-uniformity is imaged one to one (like critical illumination) and the field goes dark beyond vignetting_edge_mm = (panel / 2) / (1 + h_panel / h_camera).
• part="matte": a Lambertian part (albedo 1) returns R T E / pi, with E the irradiance of the panel (numerical sum over an *n_panel* x *n_panel* grid; the closed form for a uniform rectangle is matte_centre_closed). *n_panel* = None uses 32.
*panel_radiance*: None = uniform 1, or a 2-D map laid over the panel square. Returns also image, uniformity (illumination_uniformity of the central 80 %; None when T = 0 and the image is dark by the budget, not by the geometry), panel_scale (1 + h_panel / h_camera).
Raises ValueError: R + A > 1, R = 0, a panel farther than the camera, unknown part.
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.
• poc_spectrometer_illumination — py -3.11 examples/poc_spectrometer_illumination.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 · defect_contrast · lighting_sweep · illumination_design · solid_angle_light · solid_angle_boundaries
*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.