tan_image — 2D `arithmetic` op

• Data kinds: image → image

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

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

Usage

A pointwise transform that takes the tangent of pixel values. Corresponds to HALCON's `tan_image` (computes the tangent of an image), but is an approximation with a different normalization convention.

> The detailed description below is the original text — the summary and the headings are translated.

実装は x を [0,1] にクリップし、(x-0.5) を ±0.45π の範囲へ写してから tan を掛け、結果を signed01（符号つき値を [0,1] に写す、0.5 が 0 に対応）で戻す。a, b は未使用。角度域を ±0.45π に抑えているため tan の発散（±90° 付近）には達しない。中間輝度付近で傾きが最大になり、コントラストを強めたい局所帯域を狙うのに使える。

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 · acos_image

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

tan_image — 2D arithmetic op