arithmetic op• Data kinds: image → image
• 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)
*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).*
A periodic LUT based on `(cos(2*pi*x) + 1) / 2. A version phase-shifted by pi/2 relative to sin_image: it reaches its maximum (1) at x=0, its minimum (0) at x=0.5, and then rises again. Stands in for HALCON's cos_image` (Calculate the cosine of an image.).
> The detailed description below is the original text — the summary and the headings are translated.
`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。
• gallery2d_gray_arith 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.
cos_image 0.50 0.50
▸ Load this pipeline · Load & run
• gallery2d_gray_arith — py -3.11 examples/gallery2d_gray_arith.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
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.