  Recent advances in text-to-image generation with diffusion models present
transformative capabilities in image quality. However, user controllability of
the generated image, and fast adaptation to new tasks still remains an open
challenge, currently mostly addressed by costly and long re-training and
fine-tuning or ad-hoc adaptations to specific image generation tasks. In this
work, we present MultiDiffusion, a unified framework that enables versatile and
controllable image generation, using a pre-trained text-to-image diffusion
model, without any further training or finetuning. At the center of our
approach is a new generation process, based on an optimization task that binds
together multiple diffusion generation processes with a shared set of
parameters or constraints. We show that MultiDiffusion can be readily applied
to generate high quality and diverse images that adhere to user-provided
controls, such as desired aspect ratio (e.g., panorama), and spatial guiding
signals, ranging from tight segmentation masks to bounding boxes. Project
webpage: https://multidiffusion.github.io
