watermedia 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.ocean_spectrum(wind_speed_mps, fetch_m=None, kind='pierson_moskowitz', omega=None, gamma=3.3) -> 'dict' (to call the implementation directly, import watermedia; watermedia.ocean_spectrum(wind_speed_mps, fetch_m=None, kind='pierson_moskowitz', omega=None, gamma=3.3) -> 'dict'; from the registry, opsoptics.get("ocean_spectrum"))
One-dimensional wave spectrum S(omega) of a wind sea, with its significant height and peak period -> dict.
pierson_moskowitz (Pierson & Moskowitz 1964, a fully developed sea): S = alpha g^2 omega^-5 exp(-1.25 (omega_p / omega)^4) with alpha = 0.0081 and omega_p = (4 beta / 5)^(1/4) g / U = 0.877 g / U (U is the wind speed at 10 m). Its zeroth moment is m0 = alpha U^4 / (4 beta g^2) so Hs = 4 sqrt(m0) = 0.2092 U^2 / g (the rule of thumb is 0.21 U^2 / g); hs_closed_form_m is that value (None where there is no closed form) and hs_m the numerical integral of the returned spectrum. jonswap (Hasselmann et al. 1973) multiplies the same shape by the peak enhancement gamma ** exp(-(omega - omega_p)^2 / (2 sigma^2 omega_p^2)) (gamma = 3.3, sigma = 0.07 below the peak and 0.09 above). With fetch_m the fetch-limited alpha = 0.076 (U^2 / (F g))^0.22 and omega_p = 22 (g^2 / (U F))^(1/3) are used, without it the fully developed Pierson-Moskowitz alpha and omega_p: JONSWAP with gamma = 1 is then exactly Pierson-Moskowitz. omega is an optional increasing grid (rad/s); the default is 6000 points on a logarithmic grid from 0.15 to 25 times omega_p. The table has omega, S, hs_m, tp_s (2 pi / omega_p), omega_peak (the parameter), omega_peak_numeric (the maximum of S) and m0. A negative or zero wind or fetch is refused; fetch_m with the fully developed kind is refused too.
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_water_transparent_media — py -3.11 examples/poc_water_transparent_media.py
table as input)abcd_matrix · wavefront_stats · sfr_from_edge · paraxial_trace · seidel_coefficients · spot_stats · tolerance_analysis · wavefront_from_opd
watermedia)ocean_height_field · fresnel_water_air · snell_window · refracted_view · water_attenuation · underwater_image · phase_function_hg · scattering_phase_petzold
*Provenance: watermedia.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.