Universal Correspondence Network
We present a deep learning framework for accurate visual correspondences and demonstrate its effectiveness for both geometric and semantic matching, spanning across rigid motions to intra class shape or appearance variations. In contrast to previous CNN based approaches that optimize a surrogate patch similarity objective, we use deep metric learning to directly learn a feature space that preserves either geometric or semantic similarity. Our fully convolutional architecture, along with a novel correspondence contrastive loss allows faster training by effective reuse of computations, accurate gradient computation through the use of thousands of examples per image pair and faster testing with $O(n) feed forward passes for $n$ keypoints, instead of $O(n^2) for typical patch similarity methods. We propose a convolutional spatial transformer to mimic patch normalization in traditional features like SIFT, which is shown to dramatically boost accuracy for semantic correspondences across intra class shape variations. Extensive experiments on KITTI, PASCAL, and CUB 2011 datasets demonstrate the significant advantages of our features over prior works that use either hand constructed or learned features.
NIPS