  Vision Transformer (ViT) has gained increasing attention in the computer
vision community in recent years. However, the core component of ViT,
Self-Attention, lacks explicit spatial priors and bears a quadratic
computational complexity, thereby constraining the applicability of ViT. To
alleviate these issues, we draw inspiration from the recent Retentive Network
(RetNet) in the field of NLP, and propose RMT, a strong vision backbone with
explicit spatial prior for general purposes. Specifically, we extend the
RetNet's temporal decay mechanism to the spatial domain, and propose a spatial
decay matrix based on the Manhattan distance to introduce the explicit spatial
prior to Self-Attention. Additionally, an attention decomposition form that
adeptly adapts to explicit spatial prior is proposed, aiming to reduce the
computational burden of modeling global information without disrupting the
spatial decay matrix. Based on the spatial decay matrix and the attention
decomposition form, we can flexibly integrate explicit spatial prior into the
vision backbone with linear complexity. Extensive experiments demonstrate that
RMT exhibits exceptional performance across various vision tasks. Specifically,
without extra training data, RMT achieves **84.8%** and **86.1%** top-1 acc on
ImageNet-1k with **27M/4.5GFLOPs** and **96M/18.2GFLOPs**. For downstream
tasks, RMT achieves **54.5** box AP and **47.2** mask AP on the COCO detection
task, and **52.8** mIoU on the ADE20K semantic segmentation task. Code is
available at https://github.com/qhfan/RMT

Computer Vision and Pattern Recognition