Discriminative Subspace Alignment for Unsupervised Visual Domain Adaptation

We address the problem of unsupervised visual domain adaptation for transferring category models from one visual domain or image data set to another. We present a new unsupervised domain adaptation algorithm based on subspace alignment. The core idea of our approach is to reduce the discrepancy between the source domain and the target domain in a latent discriminative subspace. Specifically, we first generate pseudo-labels for the target data by applying spectral clustering to a cross-domain similarity matrix, which is built from sparse coefficients found in a low-dimensional latent space. This coarse alignment between the two domains exploits the assumption that the collection of data of different classes from both domains can be viewed as samples from a union of low-dimensional subspaces. Then, we create discriminative subspaces for both domains using partial least squares correlation. Finally, a mapping which aligns the discriminative source subspace into the target one is learned by minimizing a Bregman matrix divergence function. Experimental results on benchmark cross-domain visual object recognition data sets and cross-view scene classification data sets demonstrate that the proposed method outperforms the baselines and several state-of-the-art competing methods.