transform 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.stft_cola_check(window='hann', win=256, hop=None) (implementation को सीधे call करना हो तो import acoustics; acoustics.stft_cola_check(window='hann', win=256, hop=None), registry से लेना हो तो opsacoustics.get("stft_cola_check"))
क्या यह (window, hop) जोड़ी COLA को संतुष्ट करती है, और कितनी सटीकता से?
> नीचे का विस्तृत विवरण मूल text में है — सारांश और headings का अनुवाद हो चुका है।
COLA — the analysis windows summing to a constant over the hop lattice — is what lets plain overlap-add work without a division. It is *not* required by istft, which is weighted, but it is required by anything that overlap-adds modified frames without renormalising, and getting it wrong produces a periodic amplitude ripple at rate/hop Hz that looks like tremolo rather than like a bug.
Returns a dict: cola (bool), constant (the mean of the overlap sum), max_deviation (absolute), relative_deviation, nola (bool), min_squared_sum, plus the geometry.
Measured (periodic windows, relative_deviation of the plain sum):
======== ==== ==== ================== ======== ====
window win hop relative_deviation constant COLA
======== ==== ==== ================== ======== ====
hann 256 128 4.44e-16 1.00 yes
hann 256 64 2.22e-16 2.00 yes
hann 256 85 1.48e-03 1.506 no
hamming 256 128 2.06e-16 1.08 yes
blackman 256 128 1.91e-01 0.84 no
blackman 256 64 3.97e-16 1.68 yes
boxcar 256 128 0.00e+00 2.00 yes
======== ==== ==== ================== ======== ====
The two blackman rows are the useful ones: the same window is COLA at hop = win/4 and 19 % off at hop = win/2, so "which window" is not the question — the pair is. The boxcar row was worth measuring rather than
assuming: a rectangular window at 50 % overlap sums to exactly 2 and is COLA, which is the opposite of the usual intuition about it. Note also that the constant is not 1 in general — an overlap-add that does not divide by it is off by a *gain*, which is the failure that looks like a working system.
Raises ValueError: unknown / all-zero window, hop outside [1, win], win outside [2, MAX_WINDOW].
• acoustic_condition_monitoring 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।
• acoustic_condition_monitoring — py -3.11 examples/acoustic_condition_monitoring.py
table को input के रूप में लेते हैं)transform)*Provenance: acoustics.py — ACOUSTICS 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.