Generating soft labels used for training a unified model is achieved by unification of models having respective target classes with distillation. A collection of samples is prepared. Predictions are generated by individual trained models. Individual trained models have an individual class set to form a unified class set that includes target classes. The unified soft labels are estimated for each sample over the target classes in the unified class set from the predictions using a relation connecting a first output of each individual trained model and a second output of the unified model. The unified soft labels are output to train a unified model having the unified class set.