Investigation of the Efficiency of Unsupervised Learning for Multi-task Classification in Convolutional Neural Network

In this paper, we analyze the efficiency of unsupervised learning features in multi-task classification, where the unsupervised learning is used as initialization of Convolutional Neural Network (CNN) which is trained by a supervised learning for multi-task classification. The proposed method is based on Convolution Auto Encoder (CAE), which maintains the original structure of the target model including pooling layers for the proper comparison with supervised learning case. Experimental results show the efficiency of the proposed feature extraction method based on unsupervised learning in multi-task classification related with facial information. The unsupervised learning can produce more discriminative features than those by supervised learning for multi-task classification.