csi_design — INTERFEROMETRY design op

• 데이터 종류: 없음 → table(인자만으로 정해지는 연산자 —— 이미지나 데이터 입력을 받지 않습니다)

• 호출: import fullseye as fs; fs.ledger.csi_design(wavelength_um=0.6, bandwidth_um=0.1, z_range_um=12.0, width_px=640, height_px=480, min_visibility=0.3, step_divisor=8.0)(구현을 직접 호출하려면 import interferometry; interferometry.csi_design(wavelength_um=0.6, bandwidth_um=0.1, z_range_um=12.0, width_px=640, height_px=480, min_visibility=0.3, step_divisor=8.0), 원장에서 가져오려면 opsinterferometry.get("csi_design"))

사용법

광원 스펙트럼으로부터 정해지는 간섭성 주사계의 축방향 한계.

> 아래 상세 설명은 원문입니다 —— 요약과 제목은 번역되어 있습니다.

The counterpart of visiondesign for the *vertical* axis: closed-form answers to the questions asked before any hardware is bought — how localised is the coherence peak, how finely must the scan step, how many planes is that, and how much memory does the stack need.

Returned dict:

• coherence_length_um — (4 ln2 / pi) * lambda^2 / delta_lambda, the FWHM of |gamma(OPD)| for a Gaussian source (Born & Wolf 7.5.8). This is a property of the optical path difference. Verified in the tests against a direct numerical Fourier transform of the Gaussian source spectrum, at three (lambda, delta_lambda) settings, agreeing to 6 significant figures.

• envelope_fwhm_um — half of that: the width of the envelope along the scan axis, because the double pass makes OPD = 2z. This is the one to hand to csi_signal_simulate / csi_stack_simulate, and the two are reported separately precisely because collapsing them into one name called "coherence length" is a clean factor-of-two error in every height the module produces. (It was one during development, and the numerical check above is what caught it.)

• envelope_sigma_um — envelope_fwhm_um as a Gaussian sigma.

• fringe_period_um — lambda/2. The double pass halves it, and this is the number that makes phase-shifting ambiguous above lambda/4.

• max_z_step_um — lambda/4. The Nyquist ceiling on the scan step; csi_peak_position and csi_height_map refuse at or above it. It is a rejection bound, not an operating point — the accuracy is already gone well before the refusal. Measured on a tilted plane (lambda 0.6 um, bandwidth 0.12 um, ceiling 0.15 um, no noise at all, so every number below is method error):

========== =========== ===========

step [um] bias [nm] RMSE [nm]

========== =========== ===========

0.0375 0.09 0.22

0.0750 (rec) 0.09 0.26

0.1000 -0.07 0.39

0.1200 0.39 2.90

0.1400 -4.75 134.64

0.1499 -1.89 18.38

========== =========== ===========

A step of 0.14 um is accepted and returns heights that are wrong by

500x the recommended step's error, with a worst pixel at 198 nm.

Note also that the last two rows are not monotone: 0.1499 is better

than 0.1400. The error near the ceiling is an aliasing beat between the

fringe period and the step, not a smooth degradation, so "just under the

limit" cannot be made safe by nudging the step. Use

recommended_z_step_um; the bias only stays in the 0.1 nm range up to

about lambda/6.

• recommended_z_step_um — lambda/step_divisor (default lambda/8, the usual 90-degree-per-plane choice), reported only if it is below the ceiling.

• capture_range_um — the height interval over which the fringe contrast stays above *min_visibility* of its peak, 2*sigma*sqrt(2 ln(1/min_visibility)). Outside it a surface produces fringes too faint to locate, whatever the scan range is.

• planes_per_envelope — how many scan planes fall inside envelope_fwhm_um at the recommended step. Below ~4 the three-point estimators have nothing to fit.

• n_planes / stack_elements / stack_megabytes — the scan you are about to run and the float64 stack it produces, plus stack_within_cap against MAX_STACK_ELEMENTS. This is the number people discover after waiting for the scan.

• phase_unambiguous_step_um — lambda/4, the largest surface step phase-shifting interferometry can measure without a fringe-order error. It is here so the two families can be compared in one place: coherence scanning has no such limit inside the scan range, and that is the entire reason to pay for the scan.

What this deliberately does not return is a vertical *repeatability* — a "resolution" in nanometres. That number depends on the signal-to-noise ratio and on which of ESTIMATORS you use, the estimators do not even rank the same way with and without noise, and an attempt to verify the textbook "two surfaces closer than the coherence length are unresolved" criterion against this module's own forward model failed: two reflectors 0.4 coherence lengths apart still produce two envelope maxima, because the two interferograms interfere with each other and the envelope of a sum is not the sum of the envelopes. Rather than assert a formula that its own tests contradict, this operator returns only quantities it can verify, and the measured estimator table lives in the module docstring.

Raises ValueError: non-real / non-finite / string / bool parameters, a non-positive wavelength / bandwidth / range, a *bandwidth_um* at or above *wavelength_um* (a source whose spectrum reaches zero frequency is not a quasi-monochromatic source and the coherence-length formula does not apply to it), a *min_visibility* outside (0, 1), a *step_divisor* below 4 (which would recommend a step at or past its own Nyquist ceiling), and pixel counts outside [1, 65536].

자세한 사용 가이드

• coherence_scanning 패밀리 가이드

참고(샘플 데이터·문헌)

• 샘플 데이터 카탈로그(DL URL / 라이선스) —— 2-D 는 skimage.data(BSD/public)+ 합성, 3-D 는 실데이터 소스(Stanford/PDS 등)의 DL URL.

• 연산자의 내력·참고문헌 —— 이 연산자 족의 바탕이 된 연구/기법의 출처.

• 알고리즘의 정전(저자·연도)과 용도는 위의 패밀리 사용 가이드에 적혀 있습니다.

실행 가능한 예제(이 연산자를 실제로 호출하는 검증된 샘플)

• coherence_scanning — py -3.11 examples/coherence_scanning.py

• poc_interferometry_step — py -3.11 examples/poc_interferometry_step.py

타입이 이어지는 다음 연산자(table 를 입력으로 받는 것)

—

같은 카테고리(design)

—


*Provenance: interferometry.py — INTERFEROMETRY 연산자 레지스트리. 이 op 노트는 tools/opdocs.py md 가 자동 생성합니다(직접 편집하지 마세요).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.