light_transport op• Data kinds: table × images → images
• Call: import fullseye as fs; fs.ledger.render_transport(transport, patterns, triangulation_deg=20.0, irradiance=1.0, black_level=0.0, rows=1) (to call the implementation directly, import lighttransport; lighttransport.render_transport(transport, patterns, triangulation_deg=20.0, irradiance=1.0, black_level=0.0, rows=1); from the registry, opsoptics.get("render_transport"))
Render camera images of a concave Lambertian cross-section under projector patterns, through the light-transport matrix (direct + interreflection).
The orthographic projector is tilted *triangulation_deg* from the vertical towards +x; its frame (the pattern width W_p) spans the cross-section exactly, and each patch is lit by the average of the projector pixels inside its footprint, times n·d and *irradiance*. A deactivated projector pixel still emits *black_level* (Nayar's b). The radiosity B = T E is the camera image: one column per patch, repeated over *rows* rows (the groove axis).
*transport* is a table from transport_matrix_radiosity (pass n_bounces=0 for the direct-only truth). *patterns* (images) must be constant along each column (stripes or fringes parallel to the groove):
the 2-D transport is exact only then.
Returns a list of (rows, P) images (images).
Raises ValueError: not a transport table; patterns empty, non-finite, outside [0, 1] or varying along the groove axis (a checkerboard); *triangulation_deg* outside (0, 80] or a patch facing away from the projector (it would be in shadow); *irradiance* <= 0; *black_level* outside [0, 1); *rows* not an integer in [1, 4096].
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.
• poc_interreflection_fringe_error — py -3.11 examples/poc_interreflection_fringe_error.py
images as input)film_thickness_map · separate_direct_global · micro_phase_decode
light_transport)groove_profile · form_factors_2d · transport_matrix_radiosity · high_frequency_patterns · separate_direct_global · fringe_multipath_phase_error · predict_fringe_phase_error · micro_phase_decode
*Provenance: lighttransport.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.