halcon_ext op• Data kinds: contour → feature
• Call: fullseye.apply(img, "hx_distance_sc", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: distance_sc (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_distance_sc: 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):
▸ hx_distance_sc: stages (docs site)
The minimum distance from a horizontal segment (row a*H) to the contour (a feature).
> The detailed description below is the original text — the summary and the headings are translated.
行 `a*H の水平線から、全 contour の頂点までの縦方向の距離 |row - a*H| の最小値を max(H, 1)` で割って
1 で頭打ちした `np.float64` で返す。列は見ないので、線分は画像の幅いっぱいに伸びる水平線として扱う。
• `a` → 水平線の行位置(0 で最上行、1 で最下行の 1 つ下)。
• `b` は未使用。
• contour の点が無ければ 0.0(線上に点がある場合と区別できない)。
距離は頂点までなので、隣接 2 頂点の間で線を横切る contour でも 0 にはならず「近い方の頂点の行差」になる。
点から contour までの距離は `hx_distance_pc、点から region までは hx_distance_pr`。
• 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.
threshold 0.50 0.50 sk_find_contours 0.50 0.50 hx_distance_sc 0.50 0.50
▸ Load this pipeline · Load & run
• gallery2d_halcon_ext — py -3.11 examples/gallery2d_halcon_ext.py
feature as input)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.