typed op• データ種: signal → feature
• 呼び出し: fullseye.apply(img, "tb_zero_crossing_rate", a=0.5, b=0.5) (2-D は 1 画像 + 2 スカラつまみ a,b∈[0,1] のモデル)
Fraction of adjacent samples that change sign — a cheap pitch/noisiness cue.
Exact zeros are neither a crossing nor a sign: a crossing is counted only when
the sign changes between consecutive *non-zero* samples, and the rate divides
by the number of adjacent sample pairs `len(x) - 1. So [1, 0, 1, 0, 1]` is
`0.0 and [1, 0, -1] is 0.5 (before 2026-09-02 diff(sign(x))` counted
every touch of zero as a crossing: `1.0` for both).
Typed bridge of the 1d op `zero_crossing_rate into the 2-D evolution registry: the same implementation, called under the op(v, a, b) convention. This op has no tunable parameter; a and b` are unused.
• サンプルデータ カタログ(DL URL / ライセンス) — 2-D は skimage.data(BSD/public)+ 合成、3-D は実データ源(Stanford/PDS 等)の DL URL。
• 演算子の来歴・参考文献 — この op 族の元になった研究/手法の出典。
• (まだありません)
feature を入力に取れる)typed)tb_points_to_voxel · tb_estimate_point_normals · tb_iss_keypoints · tb_angle_3points · tb_project_points · tb_render_point_depth · tb_statistical_outlier_removal · tb_radius_outlier_removal
*Provenance: ops.py — 2D 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.