trans_from_rgb — 2D `color` op

• Data kinds: color → color

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

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

Usage

Converts an RGB image to another color space (HSV / Lab / YUV / XYZ). Corresponds to HALCON's `trans_from_rgb` (conversion from RGB color space to an arbitrary color space).

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

内部は OpenCV の `cv2.cvtColor` を 8bit 経由で呼ぶだけで、変換先の

色空間そのものの定義は OpenCV の実装に従う。

a は変換先を 4 通り（HSV, Lab, YUV, XYZ の順）から選ぶ

（`min(3, int(a * 4))`）。b は未使用。8bit 量子化を経由するため、

逆変換（`trans_to_rgb`）と組み合わせても厳密には可逆でない。

Detailed usage guide

• gallery2d_color_artistic family guide

Background guides (the physics and conventions behind this op)

• colorimetry — 測色と分光の知識 — 色は「分光 × 光源 × 観測者」でしか決まらない

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_color_artistic — py -3.11 examples/gallery2d_color_artistic.py

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

identity · trans_to_rgb · linear_trans_color · principal_comp · rgb1_to_gray · rgb3_to_gray · access_channel · edges_color

Same category (`color`)

cfa_to_rgb · trans_to_rgb · linear_trans_color · principal_comp · rgb1_to_gray · rgb3_to_gray · access_channel

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

trans_from_rgb — 2D color op