order op• 데이터 종류: signal → table
• 호출: import acoustics; acoustics.angular_resample(x, rate, rpm, samples_per_rev=64)(또는 opsacoustics.get("angular_resample"))
시간 기록을 축 회전각 축으로 재표본화합니다(계산 차수 추적).
> 아래 상세 설명은 원문입니다 —— 요약과 제목은 번역되어 있습니다.
Under a changing shaft speed, a component locked to the shaft has a moving
frequency and smears across the spectrum, while a structural resonance stays
put. Resample the record so the samples are equally spaced in shaft angle
instead of in time and the situation reverses exactly: the order becomes a
single line and the resonance smears.
`rpm` is either a single number (constant speed — the transform is then a
pure rescaling) or a per-sample array on the same clock as the signal. The
cumulative revolution count is the trapezoidal integral of `rpm/60`, and
the signal is linearly interpolated onto a uniform grid in it.
Returns a dict — an angle-domain record is not put into circulation as a
plain signal, deliberately. Its samples are indexed by angle, not time, so
handing it to any op that takes a `rate` would produce frequencies in Hz
from an axis measured in revolutions: no exception, no NaN, just wrong
numbers. (Same judgement, and the same reason, as `motionmag.motion_magnify`
not exposing a bare video adapter.) The dict carries `signal`,
`angle_rev, samples_per_rev, revolutions` (total),
`whole_revolutions, rate` (the original time-domain one, for
provenance), `mean_rpm, max_order`.
`max_order is samples_per_rev / 2` — the Nyquist of the *angle* axis.
Measured: a pure order-3.5 component on a 600 -> 1800 rpm ramp, resampled at
64 samples/rev over 78 whole revolutions, reads amplitude 0.999371 in a
single bin of the order spectrum; the same component in the ordinary
spectrum peaks at 0.070203 and is 66.5 Hz wide.
Raises `ValueError: everything :func:_as_signal` refuses, a
non-positive or wrong-length `rpm, samples_per_rev` outside
`[2, 65536], an output over :data:MAX_ANGULAR_SAMPLES`, fewer than one
complete revolution in the record, and — the aliasing refusal — a
`samples_per_rev` whose implied Nyquist order needs content above the
time-domain Nyquist. Asking for 64 samples/rev on a shaft turning at 30 Hz
means representing 960 Hz, which a 100 Hz recording does not contain; the
resampler would happily manufacture it from the interpolation.
• acoustic_condition_monitoring 패밀리 가이드
• 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.
• acoustic_condition_monitoring — py -3.11 examples/acoustic_condition_monitoring.py
table 를 입력으로 받는 것)order)*Provenance: acoustics.py — ACOUSTICS 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.