Joint learning of semantic and latent attributes

As mid-level semantic properties shared across object categories, attributes have been studied extensively. Recent approaches have attempted joint modelling of multiple attributes together with class labels so as to exploit their correlations for better attribute prediction and object recognition. However, they often ignore the fact that there exist some shared properties other than nameable/semantic attributes, which we call latent attributes. Basically, they can be further divided into discriminative and non-discriminative parts depending on whether they can contribute to an object recognition task. We argue that learning the latent attributes jointly with user-defined semantic attributes not only leads to better representation for object recognition but also helps with semantic attribute prediction. A novel dictionary learning model is proposed which decomposes the dictionary space into three parts corresponding to semantic, latent discriminative and latent background attributes respectively. An efficient algorithm is then formulated to solve the resultant optimization problem. Extensive experiments show that the proposed attribute learning method produces state-of-the-art results on both attribute prediction and attribute-based person re-identification.