  We propose an attention-based approach for multimodal image patch matching
using a Transformer encoder attending to the feature maps of a multiscale
Siamese CNN. Our encoder is shown to efficiently aggregate multiscale image
embeddings while emphasizing task-specific appearance-invariant image cues. We
also introduce an attention-residual architecture, using a residual connection
bypassing the encoder. This additional learning signal facilitates end-to-end
training from scratch. Our approach is experimentally shown to achieve new
state-of-the-art accuracy on both multimodal and single modality benchmarks,
illustrating its general applicability. To the best of our knowledge, this is
the first successful implementation of the Transformer encoder architecture to
the multimodal image patch matching task.
