rgb3_to_gray — 2D color op

Data kinds: colorimage

Call: fullseye.apply(img, "rgb3_to_gray", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])

HALCON equivalent: rgb3_to_gray (the HALCON reference is a useful guide to its meaning and parameters)

rgb3_to_gray: 入力 → 出力

*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).*

Usage

Converts an RGB image to luminance (grayscale). Both HALCON's `rgb1_to_gray and rgb3_to_gray` (convert an RGB image to a grayscale image) are mapped to this single implementation.

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

ITU-R BT.601 系の重み `0.299 R + 0.587 G + 0.114 B` で輝度を計算する

固定式。a, b は未使用。

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.

Try it in Studio

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.

cfa_to_rgb 0.50 0.50
rgb3_to_gray 0.50 0.50

▸ Load this pipeline  ·  Load & run

Runnable examples (verified samples that actually call this op)

gallery2d_color_artisticpy -3.11 examples/gallery2d_color_artistic.py

Ops the type connects to (they accept image as input)

identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter

Same category (color)

cfa_to_rgb · trans_from_rgb · trans_to_rgb · linear_trans_color · principal_comp · rgb1_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).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.