oct_layer_thickness — OPTICS oct op

• Data kinds: table → table

• Call: import fullseye as fs; fs.ledger.oct_layer_thickness(ascan, n_group=None, n_interfaces=None, min_snr_db=12.0, z_range_um=None, min_separation_um=None, min_separation_fwhm=1.4, min_prominence_db=0.0, dynamic_range_db=80.0) (to call the implementation directly, import octscan; octscan.oct_layer_thickness(ascan, n_group=None, n_interfaces=None, min_snr_db=12.0, z_range_um=None, min_separation_um=None, min_separation_fwhm=1.4, min_prominence_db=0.0, dynamic_range_db=80.0); from the registry, opsoptics.get("oct_layer_thickness"))

Usage

Interface peaks of an A-scan → optical and physical layer thicknesses (table). Refuses when the interfaces cannot be separated or seen.

> The detailed description below is the original text — the summary and the headings are translated.

ピーク: 雑音の rms(oct_ascan の noise_sigma)の min_snr_db 上を超える極大(dsp.find_peaks、間隔 ≥ min_separation_um、既定は軸分解能 0.44 λ0²/Δλ の 0.8 倍)を、n_interfaces 本(強い順に選んで深さ順に並べる)。位置は dsp.peak_subbin(mode="gauss")(ガウスの頂点 = 対数放物線で厳密)。光学厚 = 隣の界面の光路の差、物理厚 = 光学厚 / n_g。n_group は層ごとの群屈折率(数・materials の名前・{"n", "n_group"} の模型)、None なら光学厚だけ。

拒否(ValueError): 見えた界面が n_interfaces より少ない(薄すぎて 2 本が 1 本に融合した / 散乱で下の界面が雑音に沈んだ / 深さ範囲の外)、または隣の界面の間隔が点像の幅(oct_ascan の psf_fwhm_um、窓込み) の min_separation_fwhm 倍より狭い —— 2 つの点像が重なると互いの頂点を引き寄せ、干渉で形も歪むので、分離して見えても厚さは偏る(1.4 倍で偏りが 1 % を切る —— PoC poc_industrial_oct の掃引)。dynamic_range_db: 探す範囲の最大のピークよりこれ以上弱い極大は数えない(窓の副ローブと数値の床 —— 雑音の無い合成や SNR が 100 dB を超える強い面では、雑音の床の上に副ローブが「界面」として立つ)。min_prominence_db > 0 なら、ピークが周りの谷から立つ高さ(scipy.signal.peak_prominences、探す範囲の中だけで数える)がそれ未満のものを界面と数えない —— 強く散乱する層(白の塗装)の中は滑らかに減衰する連続体で、その揺らぎの小さな極大を「下の面」と読まないため。メッセージに見えた本数と分解能を書く。

返り値: dict(kind="oct_layers", z_opt_um(界面)、peak_db、optical_thickness_um、group_index、thickness_um、resolution_um、snr_db・prominence_db(界面ごと)、separation_limit_um(受け入れる最小の光学厚 = min_separation_fwhm × 点像の幅)、min_thickness_um(それを層ごとの群屈折率で割った、測れる最も薄い物理厚))。

Family-wide input contract (fail-closed)

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.

Detailed usage guide

• optics_imaging family guide

References (sample data, literature)

• 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.

Runnable examples (verified samples that actually call this op)

• poc_industrial_oct — py -3.11 examples/poc_industrial_oct.py

Ops the type connects to (they accept table as input)

abcd_matrix · wavefront_stats · sfr_from_edge · paraxial_trace · seidel_coefficients · spot_stats · tolerance_analysis · wavefront_from_opd

Same category (oct)

oct_design · oct_dispersion_broadening · oct_interferogram · oct_bscan_simulate · oct_from_spectra · oct_k_linearize · oct_dispersion_estimate · oct_dispersion_compensate


*Provenance: octscan.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.