cos_image — 2D arithmetic op

Data kinds: imageimage

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

HALCON equivalent: cos_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.

`(cos(2πx) + 1) / 2 による周期 LUT。sin_image` と位相が π/2 ずれた

版で、x=0 で最大(1)、x=0.5 で最小(0)に達してから再び上がる。HALCON の

`cos_image`(Calculate the cosine of an image.)の代役。

`a, b は未使用。sin_image` と同じく非単調・非可逆な周期写像なので、

一般のコントラスト補正ではなく擬似的な等高線表現などに使う。

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_arithpy -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 · asin_image · acos_image · atan_image


*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.