from_xld — SHAPE2D descriptor op

• Data kinds: table → pairs

• Call: import fullseye as fs; fs.ledger.from_xld(contour, i=0) (to call the implementation directly, import fourierdesc; fourierdesc.from_xld(contour, i=0); from the registry, opsshape2d.get("from_xld"))

Usage

Extracts the i-th contour from an XLD contour dict ({"shape", "cs":[Nx2,...]}).

What is returned is (N,2) in (row, col) order, the same as XLD. When passing it to imagemorph, swap to (x, y) with [:, ::-1] (the "coordinate-order pitfall" at the top of the module).

Detailed usage guide

• shape_description_2d family guide

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.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• shape2d_morph_descriptor_tour — py -3.11 examples/shape2d_morph_descriptor_tour.py

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

elliptic_fourier · fourier_smooth · contour_fourier_complex · add_frame_corners · warp_tps_image · warp_piecewise_affine · morph · morph_sequence

Same category (descriptor)

elliptic_fourier · reconstruct · invariants · normalize · descriptor_distance · fourier_smooth · contour_fourier_complex · contour_epicycle_chain

*Provenance: fourierdesc.py — SHAPE2D 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.