d2_distribution — 3D shape_descriptor op

• Data kinds: points → descriptor

• Call: import fullseye as fs; fs.ledger.d2_distribution(points, bins: 'int' = 64, samples: 'int' = 100000, seed: 'int' = 0) -> 'np.ndarray' (to call the implementation directly, import descriptors3d; descriptors3d.d2_distribution(points, bins: 'int' = 64, samples: 'int' = 100000, seed: 'int' = 0) -> 'np.ndarray'; from the registry, ops3d.get("d2_distribution"))

Usage

The distribution of Euclidean distances between random point pairs (Osada 2002's D2).

Randomly draws samples pairs of distinct points (i, j) from the N points and aggregates their distances. Distances are normalised by dividing by the mean distance, so the result is invariant to rotation, translation and scale. Returns a normalised histogram (bins,) over the fixed range [0, _D2_MAX] (sum 1).

Parameters

points : array_like, shape (N, 3)

Point cloud. N >= 2 is required.

bins : int

Number of histogram bins.

samples : int

Number of point pairs to draw. More lowers the variance (sampling error ~ 1/sqrt(samples)).

seed : int

Random seed. Same seed and same point cloud give deterministically identical results.

Returns

np.ndarray, shape (bins,)

Normalised distance histogram.

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.

Runnable examples (verified samples that actually call this op)

• shape_desc_pose — py -3.11 examples_3d/shape_desc_pose.py

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

fuse_to_voxel · shape_distance

Same category (shape_descriptor)

a3_distribution · extent_signature · describe · shape_distance


*Provenance: descriptors3d.py — 3D 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.