tree op• Data kinds: table × signal → table
• Call: import fullseye as fs; fs.ledger.tree_run_length(tree, labels, background=0, zero_labels=None) (to call the implementation directly, import treemorph; treemorph.tree_run_length(tree, labels, background=0, zero_labels=None); from the registry, opsgraph.get("tree_run_length"))
Expected run length (ERL) of a skeleton under a candidate labelling of its nodes.
labels gives, for every node of the tree table, the candidate object it falls in. A run is a maximal connected piece of the tree whose nodes all carry the same label and that holds at least one edge; its length is the cable inside it (an edge belongs to a run only if both ends share the label; a lone node between two cuts is no run). Edges touching background belong to no run. Runs whose label is in zero_labels (objects that also cover another skeleton — a merge) count as length 0, as in Januszewski et al. 2018: a merged run is not trustworthy anywhere.
erl = sum(l_i^2) / L with L the whole cable — the run length a point drawn uniformly along the skeleton finds itself in (points on cut or background edges find length 0). Also returns run_lengths (one per run, merged runs already zeroed), runs, max_run, cable_length, cut_edges (both ends labelled, differently), background_edges and merged_runs.
Identities: erl == L when every node carries one non-background label; sum(run_lengths) + cut cable + background cable == L; for any labelling with k runs and no lost cable, erl >= L / k (Cauchy-Schwarz) and erl <= max_run; a path of length L cut at m equally spaced points gives exactly L / (m + 1); cut at m uniformly random points, E[erl] = 2L / (m + 2) (Dirichlet(1, .., 1)).
Raises ValueError: not a tree table; labels not one integer per node, non-finite or non-integer.
• 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.
• poc_skeleton_run_length_vs_voi — py -3.11 examples/poc_skeleton_run_length_vs_voi.py
table as input)graph_edge_consensus · graph_core_persistence · tree_morphometry · tree_sholl
tree)tree_from_swc · tree_morphometry · tree_sholl
*Provenance: treemorph.py — GRAPH 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.