CIEDE2000
Advanced Color Difference
Based on the CIELAB color space, CIEDE2000 introduces sophisticated mathematical corrections to address non-uniformity across different lightness, chroma, and hue regions. **It provides results that truly align with human visual perception.**
Real-time Perception Engine
#34f5c5#22c55eHuman Visual Perception Thresholds
Why Replace CIE76?
The older CIE76 (simple Euclidean distance) failed to account for the non-uniformity of human vision. CIEDE2000 introduces5 key perceptual corrections to become the industry standard.
Lightness Weighting (SL)
Corrects for non-linear sensitivity at different lightness levels. The human eye is most sensitive to changes in neutral grays.
Chroma Weighting (SC)
Accounts for the fact that numerical differences feel smaller in highly saturated areas. This weighting compensates for the saturation decay effect.
Hue Weighting (SH)
Human tolerance varies by hue. A trigonometric T-factor adjusts the evaluation specifically for problematic regions like greens.
Rotation Factor (RT)
Technical Highlight: Specifically corrects for the tilt of tolerance ellipses in the blue region (around 275°), vastly improving accuracy for deep blues.
Geometric Logic
Prevents discontinuities in calculation. Specifically handles the cyclical nature of hue angles crossing the 0°/360° boundary.
Algorithm Architecture
Implementation of the G-factor for blue correction. Recalculation of the adjusted a', C', and hue angle h'.
- a' = (1 + G) * a*
- C' = √(a'² + b*²)
- h' = atan2(b*, a')
Calculation of deltas for lightness, chroma, and hue, using complex geometric logic for angular differences.
- ΔL' = L₂* - L₁*
- ΔC' = C₂' - C₁'
- ΔH' = 2√(C₁'C₂') * sin(Δh'/2)
Computing SL, SC, SH and the rotation factor RT to arrive at the final perceptual distance.
- SC = 1 + 0.045 * C'bar
- SH = 1 + 0.015 * C'bar * T
- RT = -sin(2Δθ) * RC
Gamification Logic
In Dialed Color Game, the system converts player's HSB inputs to CIELAB, calculates the dE (perceptual distance) against the target, and maps it to a 0-10 score via a **Sigmoid curve**.
- Midpoint 25.25: Where dE = 25.25, the player gets 5 points. Adjusted down from ~38 as CIEDE2000 yields smaller values than CIE76.
- Slope 1.55: Controls competitiveness. High tolerance for low dE, intense mid-range competition, and prevents scores from dropping to zero on large errors.