Fig 1. Nonstationary poisson signal preserves its variance after detrending.
a) A model signal with Poisson distribution, linearly increasing trend t[n] (white line) according to equation t[n] = 0.5 ⋅ n + 10 for each sample of signal n = 1, 2…1000; b) the detrended signal is created by subtraction of the trend from the model signal; c) the pre-processed model signal after Z-score normalization.