acos_image — 2D `arithmetic` op

• Data kinds: image → image

• Call: fullseye.apply(img, "acos_image", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])

• HALCON equivalent: acos_image (the HALCON reference is a useful guide to its meaning and parameters)

Usage

> This operator's description has not been translated yet. The original text follows as it is.

`arccos(x) / π で [0,1] を [0,1] に写す逆余弦 LUT。asin_image` を

反転させた形(単調減少)で、x=0 で最大(1)、x=1 で最小(0)になる。HALCON の

`acos_image`（Calculate the arccosine of an image.）の代役。

`a, b は未使用。asin_image` と同様に端点近傍で傾きが急峻になる

(数値的に敏感)。単純な階調反転がしたいだけなら `invert_image` の方が

挙動が読みやすい。

Detailed usage guide

• gallery2d_gray_arith 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.

Runnable examples (verified samples that actually call this op)

• gallery2d_gray_arith — py -3.11 examples/gallery2d_gray_arith.py

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

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

Same category (`arithmetic`)

abs_image · sqrt_image · exp_image · log_image · sin_image · cos_image · asin_image · atan_image

*Provenance: ops.py — 2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

acos_image — 2D arithmetic op