minRGB

MinRGB is a term used in color processing to denote the component-wise minimum of the red, green, and blue channels of a color. Given a color with RGB components (R, G, B), minRGB returns min(R, G, B). The components may be in the range 0–255 for 8-bit images or 0.0–1.0 for normalized color values; the resulting minRGB value lies in the same scale as the input.

MinRGB is not a perceptual luminance measure. It emphasizes the darkest channel and can be sensitive to noise in any channel. It is therefore most appropriate for computational tasks where a simple, channel-agnostic indicator of darkness is sufficient rather than an accurate brightness representation.

Applications include simple grayscale surrogates, thresholding, and color-based segmentation. It can be used as a lightweight statistic in pipelines that need a fast estimate of darkness or to constrain color ranges in masking operations. It is sometimes combined with other channel statistics, such as the maximum channel, to form more robust features.

Related concepts include maxRGB, which uses max(R, G, B), and other channel-based metrics such as median or luminance-based formulas used for grayscale conversion. MinRGB may appear in tutorials and experiments as a straightforward example of per-pixel channel analysis.

Implementation: for each pixel, compute m = min(R, G, B) and assign m to the output pixel’s r, g, b channels or to a single grayscale channel depending on the pipeline.