  Various stuff and things in visual data possess specific traits, which can be
learned by deep neural networks and are implicitly represented as the visual
prior, e.g., object location and shape, in the model. Such prior potentially
impacts many vision tasks. For example, in conditional image synthesis, spatial
conditions failing to adhere to the prior can result in visually inaccurate
synthetic results. This work aims to explicitly learn the visual prior and
enable the customization of sampling. Inspired by advances in language
modeling, we propose to learn Visual prior via Generative Pre-Training, dubbed
VisorGPT. By discretizing visual locations of objects, e.g., bounding boxes,
human pose, and instance masks, into sequences, VisorGPT can model visual prior
through likelihood maximization. Besides, prompt engineering is investigated to
unify various visual locations and enable customized sampling of sequential
outputs from the learned prior. Experimental results demonstrate that VisorGPT
can effectively model the visual prior, which can be employed for many vision
tasks, such as customizing accurate human pose for conditional image synthesis
models like ControlNet. Code will be released at
https://github.com/Sierkinhane/VisorGPT.
