signal opsignal → signalimport fullseye as fs; fs.ledger.local_std(x, window=9) (実装を直接呼ぶなら import dsp; dsp.local_std(x, window=9)、台帳から引くなら ops1d.get("local_std"))Rolling standard deviation with a stated error bound.
The 1-D counterpart of the image operator local_std (HALCON’s
deviation_image): the variance is taken after subtracting the mean
(E[x^2] - E[x]^2 loses its significant digits on a signal that sits far
from zero), unbiased by n/(n-1), and the residual bias of the square root
removed by c4(n), so the estimate of sigma itself is unbiased.
window is the number of samples in the sliding window, rounded up to the
next odd number so the window can be centred (10 becomes 11). The error
bound below is computed from the window actually used, so the number quoted
stays true. The 2-D side does the same thing — _k(a) snaps the knob to
3/5/7/9 — and the typed bridge that exposes this op as tb_local_std
scales the knob continuously, so an even value arrives whenever the knob
lands between two odd ones.
The relative standard error of each estimate is 1/sqrt(2(n-1)) —
35 % for a 5-sample window, 11 % for 41. Quote it next to any noise figure:
a rolling sigma over 9 samples is +- 25 %, which is wider than most of the
changes people try to read off it.
Returns an array the same length as x (the ends are reflected).
py -3.11 examples/gallery2d_texture_freq.pysignal を入力に取れる)create_funct_1d_array · create_funct_1d_pairs · smooth_funct_1d_gauss · smooth_funct_1d_mean · derivate_funct_1d · integrate_funct_1d · zero_crossings_funct_1d · local_min_max_funct_1d
signal)lowpass · highpass · bandpass · envelope · rms · quantize · companding_mu_law · resample
Provenance: dsp.py — ONED operator registry. この per-op ノートは tools/opdocs.py md が自動生成(手編集しない)。
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.