A computer implemented method constructs a classifier for classifying test
data. High-level features are generated from low-level features extracted
from training data. The high level features are positive definite
matrices in a form of an analytical manifold. A subset of the high-level
features is selected. An intrinsic mean matrix is determined from the
subset of the selected high-level features. Each high-level feature is
mapped to a feature vector onto a tangent space of the analytical
manifold using the intrinsic mean matrix. Then, an untrained classifier
model can be trained with the feature vectors to obtain a trained
classifier. Subsequently, the trained classifier can classify unknown
test data.