signal op• 数据种类:signal → image2d
• 调用: import fullseye as fs; fs.ledger.spectrogram(x, rate=1.0, win=256, hop=None)(要直接调用实现,import dsp; dsp.spectrogram(x, rate=1.0, win=256, hop=None);从台账取用则 ops1d.get("spectrogram"))
• 经台账调用的返回值: fullseye.ledger.spectrogram(...) 只返回声明的 out 类型 image2d 的值(底层函数还会返回辅助信息)。需要被丢弃的部分时,使用 fullseye.ledger.spectrogram.raw(...),或直接调用 dsp.spectrogram。
• 底层返回: (freqs, times, S) — S が本体
> 该算子的说明尚无译文,以下照原文给出。
STFT magnitude spectrogram -> (freqs, times, S) with S shape (n_freqs, n_frames). Hann-windowed; *hop* defaults to win//2.
Same raw convention as spectrum, but a different divisor. Each column is the unnormalised |rfft(frame * hann(win))|, so it is not an amplitude either — and dividing by 2/win is *wrong* here, because the Hann window has already thrown away part of the signal. The correct one-sided amplitude conversion divides by the window's coherent gain::
w = np.hanning(win)
amp = S * (2.0 / w.sum()) # bins 1 .. win/2-1; DC / Nyquist: 1/w.sum()
Measured on a unit sine at a bin centre (rate = 16000 Hz, 1000 Hz, amplitude exactly 1.0, win = 256): the raw column peak is 63.7497786196906; * 2/win gives 0.49804514546633283 (too small by exactly the Hann coherent gain sum(w)/win = 0.498046875), while * 2/sum(w) gives 0.9999965273676957. Only the second one is the amplitude that was actually in the signal.
Peak *positions*, frame-to-frame ratios and any dB *difference* are unaffected by either factor. This function returns magnitudes only — the phase is discarded, so it cannot be inverted; use acoustics.stft / acoustics.istft for a round-trip.
• 示例数据目录(下载 URL / 许可证) —— 2-D 用 skimage.data(BSD/公有领域)加合成图,3-D 给出真实数据源(Stanford/PDS 等)的下载 URL。
• 算子来历与参考文献 —— 该算子族所依据的研究/方法出处。
• 算法的正典(作者、年份)与用途见上面的族使用指南。
• acoustic_condition_monitoring — py -3.11 examples/acoustic_condition_monitoring.py
image2d 作为输入)—
signal)lowpass · highpass · bandpass · envelope · rms · local_std · quantize · companding_mu_law
*Provenance: dsp.py — ONED 算子登记表。本条目由 tools/opdocs.py md 自动生成(请勿手工编辑)。*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.