Figure 2
From: Unsupervised estimation of signal-dependent CCD camera noise
![Figure 2](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1687-6180-2012-231/MediaObjects/13634_2011_Article_347_Fig2_HTML.jpg)
Original piecewise-smooth test image taken from [[5]]: (a) noise-free original; (b) corrupted with simulated optoelectronic noise (77% photon, 23% electronic, SNR=17 dB); (c) variance-to-mean scatterplot of original; (d) variance-to-mean scatterplot of noisy version.