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rgb2lab: RGB to LAB Color Space Conversion

Perceptual Color Space Transformation​

The rgb2lab function converts RGB values to the perceptually uniform LAB color space through the CIE XYZ intermediate space. This enables accurate color difference calculations and perceptual color manipulations.

Transformation Pipeline​

The conversion follows a two-stage process:

RGB→Linear TransformXYZ→Cube RootLAB\text{RGB} \xrightarrow{\text{Linear Transform}} \text{XYZ} \xrightarrow{\text{Cube Root}} \text{LAB}

First, RGB values are transformed to XYZ using the sRGB matrix. Then XYZ coordinates are converted to LAB using the CIE LAB formula with D65 illuminant normalization.

The LAB space provides three components: L* (lightness from 0-100), a* (green-red axis from -127 to +127), and b* (blue-yellow axis from -127 to +127).

RGB to LAB Color Analysis​

ライブエディター
const fragment = () => {
      const rgbColor = vec3(uv.x, uv.y, 0.5)
      const labColor = rgb2lab(rgbColor)
      return vec4(labColor, 1)
}