SNR Calculator
Compute the signal-to-noise ratio for a CMOS image sensor pixel under various operating conditions. Understand the interplay between quantum efficiency, pixel size, noise sources, and scene illumination.
SNR & Photon Transfer Curve Calculator
Calculate signal-to-noise ratio and related metrics for a CMOS pixel given sensor parameters.
Signal
6000 e⁻
Total Noise
77.48 e⁻
SNR
77.4 (37.8 dB)
Dynamic Range
72.0 dB
Pixel is saturated! Signal capped at full well capacity.
Photon Transfer Curve (PTC)
SNR vs Illuminance
Noise Sources
| Source | Formula | Dominant Regime |
|---|---|---|
| Shot noise | √(signal) | Bright scenes |
| Dark current | √(I_dark × t_int) | Long exposures |
| Read noise | constant | Low light |
Total noise = √(shot² + dark² + read²)
Key Metrics
- SNR (dB) = 20 × log₁₀(signal / total_noise)
- Dynamic range = 20 × log₁₀(full_well / read_noise) — the ratio between the brightest and dimmest signals a pixel can capture