design op• Data kinds: कोई नहीं → table (केवल arguments से तय होने वाला op — यह कोई image या data input नहीं लेता)
• Call: 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) (implementation को सीधे call करना हो तो 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), registry से लेना हो तो opsinterferometry.get("csi_design"))
source spectrum से coherence-scanning setup की axial सीमाएँ।
> नीचे का विस्तृत विवरण मूल text में है — सारांश और headings का अनुवाद हो चुका है।
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].
• coherence_scanning family guide
• Sample data catalog (DL URL / license) — 2-D के लिए skimage.data (BSD/public) + synthetic, 3-D के लिए real data sources (Stanford/PDS आदि) के DL URL।
• Operators का स्रोत और संदर्भ — इस op family के मूल research/methods के स्रोत।
• Algorithm का मानक स्रोत (लेखक, वर्ष) और उपयोग ऊपर की family usage guide में दिए गए हैं।
• coherence_scanning — py -3.11 examples/coherence_scanning.py
• poc_interferometry_step — py -3.11 examples/poc_interferometry_step.py
table को input के रूप में लेते हैं)—
design)—
*Provenance: interferometry.py — INTERFEROMETRY operator registry. यह per-op note tools/opdocs.py md से अपने-आप generate होता है (हाथ से edit न करें)।*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.