essential_8point — 3D two_view op

• Data kinds: image2d × image2d → matrix

• Call: import fullseye as fs; fs.ledger.essential_8point(pts1, pts2, K1, K2=None) (to call the implementation directly, import twoview; twoview.essential_8point(pts1, pts2, K1, K2=None); from the registry, ops3d.get("essential_8point"))

Usage

The essential matrix E directly from correspondences and K. → E (3,3).

Procedure: estimate F with fundamental_8point(pts1, pts2), form E = K2ᵀ F K1, then use SVD to replace the singular values with (1, 1, 0) (the property of the essential matrix; the Frobenius norm of the result is fixed at √2).

• K1 (3,3) is the intrinsic matrix of image 1; if K2 is omitted, K1 is used for both images (assumes the same camera).

• Correspondences are (N,2) pixel coordinates. Validation and exceptions are the same as fundamental_8point (fewer than 8 points, mismatched point counts, non-finite, or input that is not (N,2) gives ValueError).

• The sign of E is indeterminate, and (R, t) splits into 4 candidates. recover_pose does the decomposition and the disambiguation by cheirality all together.

• Defenceless against outliers. The planar / pure-rotation degeneracy is not detected by this op either (recover_pose detects it). Deterministic.

Background guides (the physics and conventions behind this op)

• depth_sensors — Depth sensors — ranging principles, real-device figures, how dropouts appear

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)

• sfm_recon — py -3.11 examples_3d/sfm_recon.py

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

fuse_to_voxel

Same category (two_view)

fundamental_8point · recover_pose · triangulate · sampson_distance


*Provenance: twoview.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.