Color Accuracy Analyzer
Evaluate color reproduction accuracy of a sensor by computing the Color Correction Matrix and measuring color error against standard ColorChecker patches.
Color Accuracy Analyzer
Compute color reproduction accuracy (deltaE) for ColorChecker patches using TMM-based QE spectra and a least-squares Color Correction Matrix.
Average deltaE
28.73
Max deltaE
58.59
Excellent (deltaE < 3)
0%
Sensor QE Spectrum
Color Correction Matrix (CCM)
| Rin | Gin | Bin | |
|---|---|---|---|
| Rout | 0.0217 | -0.0004 | -0.0007 |
| Gout | -0.0170 | 0.0237 | 0.0001 |
| Bout | 0.0035 | -0.0155 | 0.0151 |
ColorChecker Patches (24)
Dark Skin
18.9
Light Skin
29.2
Blue Sky
40.8
Foliage
24.8
Blue Flower
36.4
Bluish Green
41.6
Orange
24.0
Purplish Blue
27.1
Moderate Red
12.3
Purple
19.2
Yellow Green
58.6
Orange Yellow
35.5
Blue
21.4
Green
20.0
Red
6.7
Yellow
49.6
Magenta
23.4
Cyan
44.5
White
29.1
Neutral 8
28.5
Neutral 6.5
27.8
Neutral 5
26.1
Neutral 3.5
23.6
Black
20.4
deltaE per Patch
a*b* Chromaticity Diagram
CIE xy Gamut Coverage
sRGB: 100% DCI-P3: 100% BT.2020: 100%
Physics
A sensor's raw RGB response does not directly correspond to human color perception. Color accuracy analysis bridges this gap through a calibrated pipeline:
Pipeline
- Spectral sensitivity — the sensor's RGB spectral response is convolved with each ColorChecker patch reflectance spectrum under D65 illumination to produce raw RGB triplets.
- Color Correction Matrix (CCM) — a 3x3 matrix maps raw sensor RGB to CIE XYZ tristimulus values. The CCM is computed via least-squares regression against known patch XYZ values.
- Delta E (DE*ab) — the perceptual color error is computed in CIELAB space. DE*ab < 1 is imperceptible; DE*ab > 3 is noticeable.
What Affects Color Accuracy
- Filter spectral shape — narrower filters improve color separation but reduce sensitivity
- IR contamination — silicon responds to NIR light that the eye does not see, causing color shifts without an IR-cut filter
- Illuminant mismatch — a CCM optimized for D65 may perform poorly under tungsten or fluorescent lighting
INFO
The 24-patch Macbeth ColorChecker is the industry standard target for camera color calibration and the basis for most published sensor color accuracy benchmarks.