area_opening_attr — SEGMENTATION `graph` op

• Data kinds: image2d → table

• Call: import fullseye as fs; fs.ledger.area_opening_attr(image, threshold: 'float' = 16.0, *, attribute: 'str' = 'area', connectivity: 'int' = 4) -> 'Dict[str, object]' (to call the implementation directly, import seggraph; seggraph.area_opening_attr(image, threshold: 'float' = 16.0, *, attribute: 'str' = 'area', connectivity: 'int' = 4) -> 'Dict[str, object]'; from the registry, opssegmentation.get("area_opening_attr"))

Usage

Attribute opening (Salembier et al. 1998): removes the component-tree nodes whose attribute < threshold and sets each pixel to the value of its nearest ancestor with attribute ≥ threshold (area_opening_attr).

attribute = "area" (pixel count; same as skimage's area_opening, "remove bright structures whose area is below the threshold") or "diameter" (long side of the bounding rectangle, skimage's diameter_opening). Both are increasing attributes of the 2-valued set, so the result is an algebraic opening = idempotent, anti-extensive and increasing. "Height", which depends on the maximum within the component, is not a set attribute (like h-maxima) and is not idempotent, so it is not offered (measured: the values changed on the 2nd application).

Returns: image (result of the opening), n_nodes_kept / n_nodes, removed (number of pixels whose value decreased).

Detailed usage guide

• halcon_segmentation family guide

Background guides (the physics and conventions behind this op)

• graph_hierarchy_and_thresholds — Segmentation from graph, hierarchy and threshold theorems — what is exact, and where the partition breaks down

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)

• poc_graph_hierarchy_segmentation — py -3.11 examples/poc_graph_hierarchy_segmentation.py

Ops the type connects to (they accept `table` as input)

class_ndim_norm

Same category (`graph`)

graph_cut_binary · alpha_expansion · statistical_region_merging · max_tree · quasi_flat_zones · alpha_tree · hierarchical_watershed · ultrametric_contour_map

*Provenance: seggraph.py — SEGMENTATION operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

area_opening_attr — SEGMENTATION graph op