piv_vorticity — PIV field op

• Data kinds: flow2d → image2d

• Call: import fullseye as fs; fs.ledger.piv_vorticity(flow, spacing=1.0) (to call the implementation directly, import pivops; pivops.piv_vorticity(flow, spacing=1.0); from the registry, opspiv.get("piv_vorticity"))

Usage

Vorticity d(dx)/dy - d(dy)/dx. Counter-clockwise is positive (defined in image coordinates).

In image coordinates where rows increase downwards, up and down are reversed relative to mathematical xy coordinates. Writing this without fixing the sign silently flips the sense of rotation of vortices, so the definition is fixed in the docstring.

Args:

flow: (2, h, w).

spacing: spacing between adjacent vectors [px] (info["step"]).

Returns:

(h, w). Unit is 1/frame (if spacing is in pixels).

Detailed usage guide

• piv_displacement 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)

• piv_flow_from_particles — py -3.11 examples/piv_flow_from_particles.py

• poc_tactile_dipole_torque — py -3.11 examples/poc_tactile_dipole_torque.py

• poc_what_a_picture_cannot_check — py -3.11 examples/poc_what_a_picture_cannot_check.py

Ops the type connects to (they accept image2d as input)

piv_cross_correlate · piv_multipass · piv_deform_pass · strain_from_displacement · correlation_quality · speckle_quality

Same category (field)

piv_divergence · piv_flow_magnitude · piv_to_velocity · piv_velocity_gradient · piv_q_criterion · piv_swirling_strength · piv_strain_rate


*Provenance: pivops.py — PIV 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.