match_sh_descriptor — 3D describe op

Data kinds: voxel × voxelmeasurement

Call: import fullseye as fs; fs.ledger.match_sh_descriptor(a, b, L=8, nradii=12, device='cpu') (to call the implementation directly, import match3d; match3d.match_sh_descriptor(a, b, L=8, nradii=12, device='cpu'); from the registry, ops3d.get("match_sh_descriptor"))

GPU: this op has a GPU path (device="cuda")

Usage

The cosine similarity between two SH descriptors (rotation-invariant shape matching). Closer to 1 means a more similar shape. The voxel × SH column.

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

`sh_descriptor(a, L, nradii)sh_descriptor(b, L, nradii)` を平坦化して L2 正規化し、

内積を float で返す。帯域エネルギーは非負なので値は [0, 1](負にならない)。どちらかの

記述子が全 0(空 volume)なら 0。

• `a, b は立方体 volume(sh_descriptor` の前提)。形が違ってもよいが、shell 半径が

各 N で決まるので スケールが違う物体は別物として低く出る(スケール不変ではない)。

中心ずれにも弱い(重心で中心合わせしてから)。

• 回転には不変(帯域エネルギー)。ただし鏡像も同じ値になる。

• `ntheta/nphi` は既定(32×64)固定。同じ設定同士の比較にだけ意味がある。

• 位置は返さない。「どこにあるか」は `match_shape_3d` 等、「同じ形か」は本 op。

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)

sh_descriptor_retrievalpy -3.11 examples_3d/sh_descriptor_retrieval.py

shape_descriptorpy -3.11 examples_3d/shape_descriptor.py

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

vol_gaussian_psf · fuse_to_voxel · fresnel_reflectance · snell_angle

Same category (describe)

sh_descriptor


*Provenance: match3d.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.