Data Preprocessing

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Next, one needs to select the value of <math>epsilon</math> to use when performing [[Whitening | PCA/ZCA whitening]] (recall that this was the regularization term that has an effect of ''low-pass filtering'' the data). It turns out that selecting this value can also play an important role for feature learning, we discuss two cases for selecting <tt>epsilon</tt>:
Next, one needs to select the value of <math>epsilon</math> to use when performing [[Whitening | PCA/ZCA whitening]] (recall that this was the regularization term that has an effect of ''low-pass filtering'' the data). It turns out that selecting this value can also play an important role for feature learning, we discuss two cases for selecting <tt>epsilon</tt>:
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In PCA whitening, one also has the option of performing dimension reduction while whitening the data. This is usually an excellent idea since it can greatly speed up the algorithms (less computation and less parameters). A simple rule of thumb to choose how many principle components to retain is to keep enough components to have 99% of the variance retained (more details at [[PCA#Number_of_components_to_retain PCA PCA]])
=== Reconstruction Based Models ===
=== Reconstruction Based Models ===

Revision as of 07:00, 29 April 2011

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