lowpass — ONED signal op

• Data kinds: signal → signal

• Call: import fullseye as fs; fs.ledger.lowpass(x, rate, cutoff, order=4) (to call the implementation directly, import dsp; dsp.lowpass(x, rate, cutoff, order=4); from the registry, ops1d.get("lowpass"))

Usage

Butterworth low-pass (scipy, zero-phase filtfilt). *cutoff* must be inside `(0, rate/2)`; an out-of-Nyquist cutoff raises instead of passing the signal through. A signal too short for zero-phase filtfilt also raises (the message names the exact minimum) instead of silently coming back unfiltered.

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• degenerate_inputs — py -3.11 examples/degenerate_inputs.py

• gallery2d_texture_freq — py -3.11 examples/gallery2d_texture_freq.py

• signal_filter — py -3.11 examples/signal_filter.py

Ops the type connects to (they accept signal as input)

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

Same category (signal)

highpass · bandpass · envelope · rms · local_std · quantize · companding_mu_law · resample

*Provenance: dsp.py — ONED operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.