Unsupervised Cluster Generation

A method that may include (a) feeding multiple tagged media units to a neural network to provide, from one or more intermediate layers of the neural network, multiple feature vectors of segments of the media units; wherein the neural network was trained to detect current objects within media units; wherein the new category differs from each one of the current categories; wherein at least one media unit comprises at least one segment that is tagged as including the new object; (b) calculating similarities between the multiple feature vectors; (c) clustering the multiple feature vectors to feature vector clusters, based on the similarities; and (d) finding, out of the feature vector clusters, a new feature vector cluster that identifies media unit segments that comprise the new object.