typed op• Data kinds: points → signal
• Call: fullseye.apply(img, "tb_mean_curvature", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
*The figure is the actual output on a synthetic 128×128 input. Left: input, right: output. Point clouds are drawn as a top-down scatter (brightness = z), 1-D series as a line plot, volumes as the maximum-intensity projection along z, videos as the middle frame, complex images as magnitude; return values that are not pictures are shown as the values themselves.*
Sweeping knob a (0.1 / 0.5 / 0.9, the other knob at its default):
▸ tb_mean_curvature: knob a sweep (docs site)
*Knob b does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*
Stages (the ops that come before → this op, left to right):
▸ tb_mean_curvature: stages (docs site)
On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):
▸ tb_mean_curvature: other inputs (docs site)
Mean curvature H=(k1+k2)/2. → (N,). An orientation-dependent quantity.
> The detailed description below is the original text — the summary and the headings are translated.
normals(向き付き参照法線, (N,3))未指定時は凸側ヒューリスティクス(開面の凹/凸符号は不定)。
向き付き法線を渡すと大域向きに整合し正しい符号を出す。
補足:
• 計算は `principal_curvatures と同じ(k+1 近傍の PCA 法線 + 局所二次曲面フィット)で、(k1 + k2) / 2` を返す。単位は 1/長さ。
• 符号は凸を正とする規約で、`normals` を渡したときだけ大域的な凹/凸に対応する。未指定では開いた面の H は常に凸側(絶対値相当)。
• 近傍が 5 点未満の点は 0。`k` は N-1 に切り詰められる。
• 半径 R の球なら `1/R、円柱は 1/(2R)、平面は 0。鞍点(k1 = -k2)も 0 だが gaussian_curvature` は負になるので区別できる。
• `normals は (N,3) で有限かつ非ゼロ行(ValueError`)。決定論的。
2-D 進化レジストリへ橋渡しした 3d の op `mean_curvature。実装は同じで、呼び出し規約だけ op(v, a, b) に合わせてある。a が k(既定 25)を振る。b` は未使用。
• 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 program below has been verified to run (same input as the figure). In Studio's help this block becomes buttons that load and run it on the spot.
img_to_points 0.50 0.50 tb_mean_curvature 0.50 0.50
▸ Load this pipeline · Load & run
The examples below call the underlying ledger op mean_curvature. This bridge op is the same implementation adapted to the fn(v, a, b) convention, so the behaviour carries over unchanged (only the call form differs).
• curvature_shape_index — py -3.11 examples_3d/curvature_shape_index.py
signal as input)identity · tb_create_funct_1d_array · tb_smooth_funct_1d_gauss · tb_smooth_funct_1d_mean · tb_derivate_funct_1d · tb_integrate_funct_1d · tb_zero_crossings_funct_1d · tb_abs_funct_1d
typed)tb_points_to_voxel · tb_estimate_point_normals · tb_iss_keypoints · tb_project_points · tb_render_point_depth · tb_statistical_outlier_removal · tb_radius_outlier_removal · tb_voxel_grid_downsample
*Provenance: ops.py — 2D 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.