halcon_ext op• Data kinds: image → region
• Call: fullseye.apply(img, "hx_plateaus_center", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: plateaus_center (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):
▸ hx_plateaus_center: knob a sweep (docs site)
*Knob b does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*
On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):
▸ hx_plateaus_center: other inputs (docs site)
*The 4th column is a colour (H,W,3) input. This op handles colour without crossing channels (it does not convolve the colour channel as a third spatial axis).*
Detect the centres of the grey-value plateaus (gradient ≈ 0): the centroid pixel of each flat component, as a marker region.
> The detailed description below is the original text — the summary and the headings are translated.
Sobel 勾配振幅 `gmag を求め、gmag < (0.01 + 0.1*a) * max(gmag)` の画素を「平坦」として 8 近傍で連結成分に
分け、各成分の重心(`center_of_mass`)を四捨五入した 1 画素だけを 1 とするマーカー region を返す。
• `a` → 平坦とみなす勾配の上限(最大勾配の 1%〜11%)。大きいほど平坦域が広がりつながる。
• `b` は未使用。
• 成分が 1 つも無ければ全 0。
注意: 出力は成分 1 つにつき 1 画素で、成分の面積や形は失われる。重心は非凸な平坦域(環状など)では域外に落ちる
ことがある。しきい値が最大勾配に対する相対値なので、強いエッジが 1 本あるだけで他の緩い勾配が「平坦」側に入る。
ウォーターシェッドのマーカーや、成分数を数える用途向け。面としての平坦域が欲しいなら `hx_lowlands`。
• gallery2d_halcon_ext 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.
hx_plateaus_center 0.50 0.50
▸ Load this pipeline · Load & run
• gallery2d_halcon_ext — py -3.11 examples/gallery2d_halcon_ext.py
region as input)identity · reg_erode · reg_dilate · reg_open · reg_close · fill_holes · select_largest · remove_small
halcon_ext)hx_gen_circle · hx_gen_ellipse · hx_gen_rectangle2 · hx_gen_checker_region · hx_gen_grid_region · hx_gabor · hx_fit_surface1 · hx_fit_surface2
*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.