CCD and CMOS Sensor Design
Pixel SNR, dark charge against cooling, ADC step and dynamic range of a camera sensor, with sCMOS and cooled-CCD presets.
Signal
700.0 e⁻
QE × 1000 photons
SNR
26.41
Total temporal noise 26.50 e⁻
Dark Charge
0.0111 e⁻
1.114e-1 e⁻/s at 0 °C
Noise Floor
1.511 e⁻
3.02 DN
Dynamic Range (FW/σ_read)
84.44 dB
14.02 stops, the usual datasheet figure
Dynamic Range at this exposure
84.38 dB
14.01 stops: (min(FW, ADC full scale) − D)/noise floor
ADC Full Scale
32768 e⁻
Quantization noise 0.144 e⁻
Peak SNR √FW
158.1
Shot-noise limit at the largest signal
Dark ≤ Read Noise Below
46.0 °C
Cooling further gains little at this exposure
Dark Current Density at 25 °C
0.758 pA/cm²
q·R/p² for a 6.5 µm pixel
Full-Well Density
592 e⁻/µm²
Full well per pixel area
S = QE·N; D = R₂₅·2^((T − 25 °C)/T_d)·t; σ_q = Δ/√12, Δ in e⁻/DN
SNR = S / √(S + D + σ_read² + σ_q²)
DR = 20·log₁₀((S_max − D)/σ_floor), S_max = min(FW, K·(2^bits − 1)), σ_floor = √(σ_read² + D + σ_q²)
Dark ≤ read noise for T ≤ 25 °C + T_d·log₂(σ_read²/(R₂₅·t))
Model and references
Textbook approximation. A standard approximation from the literature (for example paraxial, plane-wave or Gaussian-beam), valid within the range the page states. About the tiers
Poisson signal and dark charge, Gaussian read noise and quantization noise Δ/√12 (Δ in e⁻/DN) add in quadrature (EMVA 1288). Dark current follows the doubling law about 25 °C, the local form of the n_i scaling. Fixed-pattern noise and nonlinearity near full well are left out; the presets are representative, not a specific camera.
- Janesick J. R. (2007). Photon Transfer: DN → λ. SPIE Press, ch. 5. Read, dark and shot noise in quadrature, full well and dynamic range. doi:10.1117/3.725073
- EMVA Standard 1288, Release 3.1 (2016). Standard for Characterization of Image Sensors and Cameras, Eq. (11) and (48). Quantization noise σ_q² = 1/12 DN² and the total SNR. emva.org
- Janesick J. R. (2001). Scientific Charge-Coupled Devices. SPIE Press. Dark current temperature dependence and dark shot noise. doi:10.1117/3.374903