Subsampling training data during artificial neural network training

Perplexity scores are computed for training data samples during ANN training. Perplexity scores can be computed as a divergence between data defining a class associated with a current training data sample and a probability vector generated by the ANN model. Perplexity scores can alternately be computed by learning a probability density function ("PDF") fitting activation maps generated by an ANN model during training. A perplexity score can then be computed for a current training data sample by computing a probability for the current training data sample based on the PDF. If the perplexity score for a training data sample is lower than a threshold, the training data sample is removed from the training data set so that it will not be utilized for training during subsequent epochs. Training of the ANN model continues following the removal of training data samples from the training data set.