Photoresponse Non-Uniformity
PRNU measures the spatial variation in pixel sensitivity across the sensor array. σPRNU = PRNU% × mean signal; DSNU is the spatial rms of the dark image.
Total noise (one frame)
547.84 e⁻
SNR 91.3 (39.2 dB)
Spatial noise
500.00 e⁻
PRNU·S 500.0 e⁻, DSNU 2.0 e⁻
Temporal noise
223.89 e⁻
shot √(S + D) 223.83 e⁻, read 5.0 e⁻
SNR after flat-field correction
223.3
47.0 dB: the spatial terms removed
Shot = PRNU at
10000 e⁻
S = 1/PRNU²; PRNU dominates above
Map rms (below)
500.0 e⁻
spatial standard deviation of the map = PRNU·S
σ_total² = S + D + σ_read² + DSNU² + (PRNU·S)² (EMVA 1288 Eq. 48). The map shows the photo response only: white pixel-to-pixel PRNU plus a shading gradient, scaled to the PRNU you enter.
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
EMVA 1288 definitions: PRNU as a fraction of the mean photo signal, DSNU in e⁻ rms, and independent Gaussian terms σ_total² = S + D + σ_read² + DSNU² + (PRNU·S)². Quantization noise is left out. The map is an illustrative pattern (white noise plus a shading gradient) scaled to the PRNU you enter; real PRNU also has column and row structure.
- EMVA Standard 1288, Release 3.1 (2016). Standard for Characterization of Image Sensors and Cameras, Eq. (23)–(25) and (45)–(48). DSNU₁₂₈₈, PRNU₁₂₈₈ and the total SNR including spatial non-uniformity. emva.org
- Janesick J. R. (2007). Photon Transfer: DN → λ. SPIE Press, ch. 5. Fixed-pattern noise σ_FPN = P_N·S, shot = FPN at S = 1/P_N², and its removal by flat-fielding. doi:10.1117/3.725073