hx_gen_derivative_filter — 2D `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)

hx_gen_derivative_filter: 入力 → 出力

*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).*

Usage

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。

Detailed usage guide

• gallery2d_halcon_ext family guide

References (sample data, literature)

• 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.

Try it in Studio

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_gen_derivative_filter 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_halcon_ext — py -3.11 examples/gallery2d_halcon_ext.py

Ops the type connects to (they accept `image` as input)

identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter

Same category (`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).*

hx_gen_derivative_filter — 2D halcon_ext op