Example of minimization result. This example is from data with Gman = 76.7, the expected gain from the manufacturer calibration. The parameters that minimize the are F = 0.46, G = 52.2, and ENF = 1.38. Diagonal: minimum as a function of ENF (top left), G (middle), and F (bottom right), the two other parameters being free. Lower left: maps of minimum . Upper right: histogram for the data with illumination in blue, histogram of the background in light green, and histogram obtained with the parameters that minimize the in orange.