Learning Data Mining with Python

Classifying Objects in Images Using Deep Learning
The following screenshot shows the Mars rover designed and used by NASA; it
made significant use of computer vision:
Deep neural networks
The neural networks we used in Chapter 8, Beating CAPTCHAs with Neural Networks,
have some fantastic theoretical properties. For example, only a single hidden layer is
needed to learn any mapping (although the size of the middle layer may need to be
very, very big). Neural networks were a very active area of research in the 1970s and
1980s, and then these networks were no longer used, particularly compared to other
classification algorithms such as support vector machines. One of the main issues
was that the computational power needed to run many neural networks was more
than other algorithms and more than what many people had access to.
Another issue was training the networks. While the back propagation algorithm has
been known about for some time, it has issues with larger networks, requiring a very
large amount of training before the weights settle.
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