The Effect of Noise and Brightness on Convolutional Deep Neural Networks

Abstract

The classification performance of Convolutional Neural Networks (CNNs) can be hampered by several factors. Sensor noise is one of these nuisances. In this work, a study of the effect of noise on these networks is presented. The methodological framework includes two realistic models of noise for present day CMOS vision sensors. The models allow to include separately Poisson, Gaussian, salt & pepper, speckle and uniform noise as sources of defects in image acquisition sensors. Then, synthetic noise may be added to images by using that methodology in order to simulate common sources of image distortion. Additionally, the impact of the brightness in conjunction with each selected kind of noise is also addressed. This way, the proposed methodology incorporates a brightness scale factor to emulate images with low illumination conditions. Based on these models, experiments are carried out for a selection of state of the art CNNs. The results of the study demonstrate that Poisson noise has a small impact on the performance of CNNs, while speckle and salt & pepper noise together the global illumination level can substantially degrade the classification accuracy. Also, Gaussian and uniform noise have a moderate effect on the CNNs.