Most existing domain adaptation methods learn with both (labeled) samples in the source domain and (unlabeled) samples in the target domain. Relying on the availability of target domain samples, however, is not always feasible in real-world applications. In this paper, we propose a new method to address this issue, in which the target domain samples do not need to be available for the task of interest. To improve the performance of such a zero-shot domain adaptation (ZSDA), we learn with not only source samples in the task of interest, but also seek additional assistance from those dual-domain samples in an irrelevant task. To overcome the problems induced by the unavailability of target samples in the task of interest, we exploit the hypothesis that the domain correlation is consistent across tasks and learn to transfer it from the irrelevant task to the task of interest. Specifically, our method aims to learn a domain-invariant representation space in which the source-domain classifier is directly transferable to the target domain. We achieve this by restricting the two domains to share both inter-category structure and intra-category structure in the representation space. Experiment results on five benchmarking datasets indicate that our proposed method significantly outperforms the existing representative baselines.

We propose a novel approach for predicting on-going action with the assistance of a low-cost depth camera. Our approach introduces a soft regression-based early prediction framework. In this framework, we estimate soft labels for the subsequences at different progress levels, jointly learned with an action predictor. Our formulation of soft regression framework 1) overcomes a usual assumption in existing early action prediction systems that the progress level of on-going sequence is given in the testing stage; and 2) presents a theoretical framework to better resolve the ambiguity and uncertainty of subsequences at early performing stage. The proposed soft regression framework is further enhanced in order to take the relationships among subsequences and the discrepancy of soft labels over different classes into consideration, so that a Multiple Soft labels Recurrent Neural Network (MSRNN) is finally developed. For real-time performance, we also introduce a new RGB-D feature called "local accumulative frame feature (LAFF)", which can be computed efficiently by constructing an integral feature map. Our experiments on three RGB-D benchmark datasets and an unconstrained RGB action set demonstrate that the proposed regression-based early action prediction model outperforms existing models significantly and also show that the early action prediction on RGB-D sequence is more accurate than that on RGB channel.

Person reidentification in a camera network is a valuable yet challenging problem to solve. Existing methods learn a common Mahalanobis distance metric by using the data collected from different cameras and then exploit the learned metric for identifying people in the images. However, the cameras in a camera network have different settings and the recorded images are seriously affected by variability in illumination conditions, camera viewing angles, and background clutter. Using a common metric to conduct person reidentification tasks on different camera pairs overlooks the differences in camera settings; however, it is very time-consuming to label people manually in images from surveillance videos. For example, in most existing person reidentification data sets, only one image of a person is collected from each of only two cameras; therefore, directly learning a unique Mahalanobis distance metric for each camera pair is susceptible to over-fitting by using insufficiently labeled data. In this paper, we reformulate person reidentification in a camera network as a multitask distance metric learning problem. The proposed method designs multiple Mahalanobis distance metrics to cope with the complicated conditions that exist in typical camera networks. We address the fact that these Mahalanobis distance metrics are different but related, and learned by adding joint regularization to alleviate over-fitting. Furthermore, by extending, we present a novel multitask maximally collapsing metric learning (MtMCML) model for person reidentification in a camera network. Experimental results demonstrate that formulating person reidentification over camera networks as multitask distance metric learning problem can improve performance, and our proposed MtMCML works substantially better than other current state-of-the-art person reidentification methods.

The general configuration of body is a valuable cue for human identification, which is ignored by the existing approaches. In this paper, we present an approach for human identification by using body prior and the generalized Earth Mover's Distance (EMD). The common knowledge that a pedestrian is composed of upper body and the lower one is employed as a body prior. To achieve more robust body segmentation, we pursue their boundary by inducing a logistic probability map, which is approximated based on minimizing its KL divergence to the posterior probability of the observed person image. Furthermore, we generalize EMD by assigning different weights to regions of body, which are learned through logistic regression to boost discriminative power for human identification. The experimental results show that both body prior and the generalized EMD facilitate performance on human identification.