A simple classifier

1
A simple classifier

• Ridge regression
• A variation on standard linear regression
• Adds a ridge term that has the effect of
• smoothing the weights
• Equivalent to training a linear network with
  weight decay.

2
A Strong ClassifierSNoW Sparse Network of
Winnows

• Roth et al. 2000 Currently best reported face
  detector
• 1. Turn each pixel into a sparse, binary vector

• 2. Activation sign( )
• 3. Train with the Winnow update rule

3
AdaBoost for Feature Selection

• Viola and Jones (2001) used AdaBoost as a feature
  selection method

• For each round of AdaBoost
• For each patch, train a classifier using only
  that one patch.
• Select the best one as the classifier for this
  round
• reweight distribution based on that classifier.

4
Results
5
AdaBoost consistently improves performance
6
AdaBoost consistently improves performance