RGB to ACI Color Matchbox

Euclidean RGB vs Human Eye: A simple distance formula in RGB space ($d = \sqrt{\Delta R^2 + \Delta G^2 + \Delta B^2}$) treats color channels linearly. However, the human eye is far more sensitive to green wavelengths than blue, and perceives brightness non-linearly.

CIE76 standard: We convert the RGB coordinates into the CIE $L^*a^*b^*$ color space. This model separates lightness ($L$) from the color channels ($a$: red-green axis, $b$: yellow-blue axis) to align mathematically with human visual perception limits.

Delta-E ($\Delta E$) Threshold values:
• $\Delta E \le 1.0$: Inappreciable (not perceptible by the human eye).
• $1.0 < \Delta E \le 2.0$: Perceptible only by close observation.
• $2.0 < \Delta E \le 10.0$: Perceptible at a glance.
• $\Delta E > 10.0$: Colors look distinctly different.