Keyphrases
- feature extraction
- face recognition
- preprocessing
- pattern classification
- linear discriminant analysis
- discriminant analysis
- image processing
- image classification
- coarse to fine
- hierarchical structure
- frequency domain
- feature selection
- dimensionality reduction
- dimension reduction
- feature vectors
- feature space
- pattern recognition
- hierarchical structures
- hierarchical classification
- unsupervised learning
- image preprocessing
- texture feature extraction
- linear feature extraction
- feature representation
- palmprint
- principal component analysis
- wavelet transform
- knn
- knowledge base