tb_elastic_deform — 2D typed op

Data kinds: pointspoints

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

tb_elastic_deform: 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_elastic_deform: stages (docs site)

On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):

tb_elastic_deform: other inputs (docs site)

Usage

Elastic deformation via a smooth random displacement field (correlation length `sigma, RMS amplitude alpha`).

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

各点に独立ガウス乱数ベクトルを置き、空間ガウス重み `exp(-d²/2σ²)` で平滑化した

変位場を生成する(近接点は coherent に動く)。場は RMS を 1 に正規化してから

`alpha 倍するので、変位の RMS ノルムはちょうど alpha になる(σ→∞` で場は

定数=剛体並進, `σ→0` で各点独立)。非剛体な物体変形/柔軟物の学習に。

注意(honest): 近傍探索は `cKDTree.query_pairs(r=3σ)σ` が雲の直径に近いほど

ペア数は O(N²) に近づくため、大規模雲では `σ` を局所スケールに保つこと。

`sigma < 0ValueErrorsigma == 0` または 1 点だけの雲では平滑化せず各点

独立の変位になる。`alpha` は検証しない(0 なら無変位、負なら場が反転するだけ)。

`seed で決定論的。返り値は float64 (N,3)` で点数・順序は保たれる(変形前後の

対応が添字で分かるので、非剛体位置合わせの誤差を直接測れる)。空入力は空を返す。

2-D 進化レジストリへ橋渡しした 3d の op `elastic_deform。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_elastic_deform 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 elastic_deform. 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).

sensor_segpy -3.11 examples_3d/sensor_seg.py

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

identity · 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

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.