assess op• Data kinds: flow2d → flow2d
• Call: import fullseye as fs; fs.ledger.piv_sample_at_windows(field, info) (to call the implementation directly, import pivops; pivops.piv_sample_at_windows(field, info); from the registry, opspiv.get("piv_sample_at_windows"))
Drops a per-pixel field (2, H, W) onto the grid of window centers (nearest neighbor).
The ground truth is made at pixel resolution, but PIV output sits on the window grid. Before comparing, it must be brought onto the same grid, and the way it is brought there (nearest neighbour or window mean) changes the error. Here it is nearest neighbour —— with the window mean, in fields with gradients it becomes impossible to tell it apart from PIV's own smoothing.
• piv_displacement family guide
• 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.
• piv_field_analysis_tour — py -3.11 examples/piv_field_analysis_tour.py
• piv_flow_from_particles — py -3.11 examples/piv_flow_from_particles.py
• poc_river_surface_velocity — py -3.11 examples/poc_river_surface_velocity.py
• poc_strain_history — py -3.11 examples/poc_strain_history.py
flow2d as input)piv_deform_pass · piv_outlier_mask · piv_replace_outliers · piv_vorticity · piv_divergence · piv_flow_magnitude · piv_to_velocity · piv_velocity_gradient
assess)piv_error_stats · piv_peak_locking · piv_time_statistics
*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.