fit_sphere3 — 3D geometry op

Data kinds: pointsprimitive

Call: import fullseye as fs; fs.ledger.fit_sphere3(points) -> 'dict' (to call the implementation directly, import measure3d; measure3d.fit_sphere3(points) -> 'dict'; from the registry, ops3d.get("fit_sphere3"))

Usage

Algebraic (Kåsa) least-squares sphere fit to `(depth, row, col)` points:

solve `|P|^2 = 2 P·c + (r^2 - |c|^2)` in the least-squares sense — exact for

points on a sphere, a standard robust estimator under moderate noise. Returns

`center (cd/cr/cc), radius r`, and the RMS radial residual. Raises

`ValueError` on < 4 points or a coplanar set (no finite sphere).

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)

primitive_fitting_3dpy -3.11 examples_3d/primitive_fitting_3d.py

roi_domain_boundarypy -3.11 examples_3d/roi_domain_boundary.py

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

fuse_to_voxel · angle_between_lines · angle_between_planes · angle_line_plane · distance_point_plane · distance_point_line · distance_line_line · distance_segment_segment

Same category (geometry)

line_from_2points · plane_from_3points · angle_3points · angle_between_lines · angle_between_planes · angle_line_plane · distance_point_plane · distance_point_line


*Provenance: measure3d.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.