morphology op• Data kinds: image → image
• Call: fullseye.apply(img, "f2_gray_inside", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: gray_inside (the HALCON reference is a useful guide to its meaning and parameters)

*The figure is the real output on a synthetic 128×128 input. Left: input, right: output (a non-image return value is shown as the value itself).*
Grayscale hole-fill: for each pixel, the lowest gray value attainable on any path to the image border == morphological reconstruction of the image by erosion from a border-anchored marker. Dark basins enclosed by brighter walls are raised toward the wall height; regions connected to the border stay dark. `a sets the maximum fill depth h (0 = none, 1 = full); b` is ignored.
• gallery2d_morphology 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.
The program below has been verified to run (same input as the figure). In Studio's help this block becomes buttons that load and run it on the spot.
f2_gray_inside 0.35 0.50
▸ Load this pipeline · Load & run
• gallery2d_morphology — py -3.11 examples/gallery2d_morphology.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
morphology)gerode · gdilate · gopen · gclose · tophat · bothat · morph_grad · sk_area_opening
*Provenance: ops.py — 2D 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.