  Recent advancements in text-to-image generative models have demonstrated a
remarkable ability to capture a deep semantic understanding of images. In this
work, we leverage this semantic knowledge to transfer the visual appearance
between objects that share similar semantics but may differ significantly in
shape. To achieve this, we build upon the self-attention layers of these
generative models and introduce a cross-image attention mechanism that
implicitly establishes semantic correspondences across images. Specifically,
given a pair of images -- one depicting the target structure and the other
specifying the desired appearance -- our cross-image attention combines the
queries corresponding to the structure image with the keys and values of the
appearance image. This operation, when applied during the denoising process,
leverages the established semantic correspondences to generate an image
combining the desired structure and appearance. In addition, to improve the
output image quality, we harness three mechanisms that either manipulate the
noisy latent codes or the model's internal representations throughout the
denoising process. Importantly, our approach is zero-shot, requiring no
optimization or training. Experiments show that our method is effective across
a wide range of object categories and is robust to variations in shape, size,
and viewpoint between the two input images.
