tb_superquadric_residual — 2D typed op

Data kinds: pointsfeature

Call: fullseye.apply(img, "tb_superquadric_residual", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])

tb_superquadric_residual: input → output

*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.*

*Knob a does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*

*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_superquadric_residual: stages (docs site)

Usage

Gross-Boult volume-corrected residual: mean( (sqrt(a1 a2 a3)(F^eps1 - 1))^2 ).

> The detailed description below is the original text — the summary and the headings are translated.

`inside_outside(points, a, eps, R, t)` で各点の内外関数 F を求め、点ごとの残差

`r_i = sqrt(a1*a2*a3) * (F_i**eps1 - 1) の 2 乗平均を float で返す。表面上の点は F=1` なので

残差 0、内側は負・外側は正の残差になる(2 乗するので符号は消える)。`fit_superquadric` が

最小化しているのと同じ量で、返り dict の `residual` もこの値。

• `points`: (N,3) にリシェイプできる点群(world 座標)。

• `a: 半径 (a1,a2,a3)。eps: 形状指数 (eps1,eps2)(F の計算には両方、外側の F**eps1` には

`eps1` だけを使う)。

• `R/t: 姿勢(X_body = R.T @ (X - t))。None` なら単位回転 / 原点。

数値保護: F は [0, 1e12] にクリップし、`a1*a2*a3` は 1e-12 以上に持ち上げてから sqrt を取る

(退化パラメータで inf/NaN にならないため。表面近傍の値には影響しない)。

次元: `sqrt(a1 a2 a3) は長さの 3/2 乗、F^eps1 - 1` は無次元なので、返り値は長さの 3 乗の

次元を持ち点群のスケールに依存する。大きさの違う物体どうしの比較には向かない。真の点-表面

ユークリッド距離ではなく半径距離近似であること、外れ値に無防備なことはモジュール docstring

のとおり。

2-D 進化レジストリへ橋渡しした 3d の op `superquadric_residual。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。この op に調整点は無く、ab` も使われない。

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.

Try it in Studio

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_superquadric_residual 0.50 0.50

▸ Load this pipeline  ·  Load & run

Runnable examples (verified samples that actually call this op)

The examples below call the underlying ledger op superquadric_residual. 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).

superquadric_fitpy -3.11 examples_3d/superquadric_fit.py

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

identity · feature_to_img

Same category (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.