throwing away too much information
http://deeplearning.net/tutorial/lenet.html
http://ufldl.stanford.edu/tutorial/supervised/Pooling/
images have the “stationarity” property, which implies that features that are useful in one region are also likely to be useful for other regions.
原文：http://www.cnblogs.com/yuanjiangw/p/7550824.html
