light_section op• Data kinds: table × table → points
• Call: import fullseye as fs; fs.ledger.light_section_profile(centers, rig) (to call the implementation directly, import lightsection; lightsection.light_section_profile(centers, rig); from the registry, opsoptics.get("light_section_profile"))
• GPU: none (CPU reference implementation only)
Triangulate line centres into 3-D points: viewing ray ∩ laser plane (points).
> The detailed description below is the original text — the summary and the headings are translated.
有効な中心ごとに視線 K⁻¹ (u, v, 1) と光面 n · X = d の交点を返す (N, 3)。装置の表が姿勢 R, t を持つなら世界座標(Z = 高さ)、無ければカメラ座標。
Returns (N, 3) points for the valid centres: in world coordinates (Z = height) when the rig carries R, t, otherwise in camera coordinates. Ground truth: a profile rendered by light_section_render (forward projection) comes back at its true heights.
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. Exception, declared: the u_map of bottle_fit_from_pattern takes pixels that could not be measured as NaN (infinity is still refused).
• 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. Exception, declared: bottle_background_map returns NaN in u_mm for pixels whose ray is unusable (total internal reflection and the like), together with a valid mask and the counts.
• 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_light_section_step_weld_floor — py -3.11 examples/poc_light_section_step_weld_floor.py
points as input)refract_rays · reflect_rays · trace_rays · illumination_visibility · env_studio · env_lightbox · form_factor_polygons
light_section)laser_line_center_centroid · laser_line_center_gauss · laser_line_center_steger · light_section_rig · light_section_targets · light_section_render · light_plane_calibrate · light_section_scan
*Provenance: lightsection.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.