Incorporating Exemplar Optimization into Training with Dual Networks for Human Mesh Recovery

We propose a novel optimization-based human mesh recovery method from a single image. Given a test exemplar, previous approaches optimize the pre-trained regression network to minimize the 2D re-projection loss, which however suffer from over-/under-fitting problems. This is because the ``exemplar optimization'' at testing time has too weak relation to the pre-training process, and the exemplar optimization loss function is different from the training loss function. (1) We incorporate exemplar optimization into the training stage. During training, our method first executes exemplar optimization and subsequently proceeds with training-time optimization. The exemplar optimization may run into a wrong direction, while the subsequent training optimization serves to correct the deviation. Involved in training, the exemplar optimization learns to adapt its behavior to training data, thereby acquires generalibility to test exemplars. (2) We devise a dual-network architecture to convey the novel training paradigm, which is composed of a main regression network and an auxiliary network, in which we can formulate the exemplar optimization loss function in the same form as the training loss function. This further enhances the compatibility between the exemplar and training optimizations. Experiments demonstrate that our exemplar optimization after the novel training scheme significantly outperforms state-of-the-art approaches.