region op• Data kinds: region → region
• Call: fullseye.apply(img, "reg_erode", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: erosion_circle (the HALCON reference is a useful guide to its meaning and parameters)
*The figure is the actual output on a synthetic 128×128 input. Left: input, right: output. Point clouds are drawn as a top-down scatter (brightness = z), 1-D series as a line plot, volumes as the maximum-intensity projection along z, videos as the middle frame, complex images as magnitude; return values that are not pictures are shown as the values themselves.*
Sweeping knob a (0.1 / 0.5 / 0.9, the other knob at its default):
▸ reg_erode: knob a sweep (docs site)
*Knob b does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*
Stages (the ops that come before → this op, left to right):
▸ reg_erode: stages (docs site)
On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):
▸ reg_erode: other inputs (docs site)
Binary erosion of a region. Equivalent to HALCON's `erosion_circle` (Erode a region with a circular structuring element.).
> The detailed description below is the original text — the summary and the headings are translated.
`a が反復回数を 1〜4（_it(a)）に振る。b は未使用。構造要素は scipy.ndimage.binary_erosion の既定（十字形、4近傍相当）で、HALCON の円形構造要素とは形が異なる（近似）。入力は v > 0.5` で二値化してから処理する。
Border handling: treat everything outside the image as background (0) (measured; tools/impl2/border_probe.py).
• gallery2d_region 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.
threshold 0.50 0.50 reg_erode 0.50 0.50
▸ Load this pipeline · Load & run
• degenerate_inputs — py -3.11 examples/degenerate_inputs.py
• gallery2d_region — py -3.11 examples/gallery2d_region.py
• poc_colocalization_crosstalk — py -3.11 examples/poc_colocalization_crosstalk.py
• poc_leaf_disease_area — py -3.11 examples/poc_leaf_disease_area.py
region as input)identity · reg_dilate · reg_open · reg_close · fill_holes · select_largest · remove_small · invert_region
region)reg_dilate · reg_open · reg_close · fill_holes · select_largest · remove_small · invert_region · dist_transform
*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.