Keyphrases
- sparse coding
- gradient ascent
- sparse representation
- natural images
- linear combination
- unsupervised learning
- generative model
- image classification
- image representation
- expectation maximization
- cross entropy
- visual words
- high dimensional
- image patches
- feature space
- exponential family
- higher order
- em algorithm
- feature selection
- supervised learning
- multiscale
- training data