koraykv / unsup

Some unsupervised learning modules using Torch
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ZCA Epsilon #10

Closed clementfarabet closed 11 years ago

clementfarabet commented 11 years ago

In the ZCA whitening function, would it be a good idea to expose the epsilon as an argument (with default value)?

It seems that it's an important knob to control the effect of noise / high-frequency content on the whitening.

Here are screenshots demonstrating that. This is k-means on image patches. The first screenshot is with the default epsilon (1e-5), the second with a higher epsilon of 1e-3, the third with and epsilon of 1e-1. These are completely empirical observations of course. Here it seems that the second one yields the best basis.

screen shot 2013-06-07 at 2 24 10 pm

screen shot 2013-06-07 at 2 23 18 pm

screen shot 2013-06-07 at 12 48 03 pm