halcon_ext op• Data kinds: image → image
• Call: fullseye.apply(img, "hx_gen_derivative_filter", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: gen_derivative_filter (the HALCON reference is a useful guide to its meaning and parameters)
A derivative filter in the frequency domain. `a is the order of the derivative, b` its direction.
> The detailed description below is the original text — the summary and the headings are translated.
HALCON の `gen_derivative_filter` は Derivative(x / y / xx / yy / xy)と
次数を取るが、ここは長らく `|f|` を正規化して返すだけで、**入力の中身も
つまみも一切見ていなかった** —— 2026-09-02 実測で、同じ形なら
`a/b` を変えても、別の絵を渡しても、返りがバイト一致だった
(兄弟の `hx_gen_lowpass / hx_gen_highpass / hx_gen_bandfilter` は
つまみで変わるので、この 1 件だけ浮いていた)。
• `a : 階数 1〜2(|f| か |f|^2`)。2 階はラプラシアンに対応する。
• `b : 向き。0 で x 方向 |f_x|、1 で y 方向 |f_y|、間は等方 |f|`
へ滑らかに混ぜる(0.5 でちょうど等方)。
返りは周波数領域のフィルタそのもの(HALCON の gen_* と同じ約束)なので、
入力は形を決めるためだけに使う。ただし形だけでなくつまみでちゃんと変わる
ようになったので、進化が階数と向きを選べる。
• 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.
• gallery2d_halcon_ext — py -3.11 examples/gallery2d_halcon_ext.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
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.