rgb_to_lab — IMGMETRICS `colorspace` op

• Data kinds: rgbimage → lab

• Call: import fullseye as fs; fs.ledger.rgb_to_lab(rgb, white=(0.95047, 1.0, 1.08883)) (to call the implementation directly, import imgmetrics; imgmetrics.rgb_to_lab(rgb, white=(0.95047, 1.0, 1.08883)); from the registry, opsimgmetrics.get("rgb_to_lab"))

Usage

sRGB → CIE L\*a\*b\* (D65). The step before measuring ΔE.

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

`xyz_to_lab(rgb_to_xyz(rgb), white)` の合成。検証と失敗条件はその 2 つに従う:

• `rgb: 最後の軸が 3。整数 dtype は dtype の最大値で [0, 1]` に正規化、

float は `[0, 1] に収まっていることを要求(外れると MetricContractError`)。

線形 RGB ではなく ガンマ付きの sRGB を渡すこと。

• `white`: Lab の白色点。sRGB の行列は D65 固定なので、通常は既定のまま。

• 返り値: 入力と同じ形の float64。`L は [0, 100]、白 (1, 1, 1)` で

`(100, 0, 0)` 付近。

画像 2 枚の色差なら `delta_e_map` が変換から色差まで一度にやる。

`lab_to_rgb` で戻せるが、色域外は切り詰められる。

Detailed usage guide

• image_difference_metrics 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)

• image_quality_metrics — py -3.11 examples/image_quality_metrics.py

• poc_colormap_readability — py -3.11 examples/poc_colormap_readability.py

• poc_leaf_disease_area — py -3.11 examples/poc_leaf_disease_area.py

• poc_solder_fillet_aoi — py -3.11 examples/poc_solder_fillet_aoi.py

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

lab_to_rgb · delta_e_2000 · delta_e_76

Same category (`colorspace`)

lab_to_rgb · rgb_to_xyz · xyz_to_lab

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

rgb_to_lab — IMGMETRICS colorspace op