Ctrl-X: Controlling Structure and Appearance for Text-To-Image Generation Without Guidance
Kuan Heng Lin1*    Sicheng Mo1*    Ben Klingher1    Fangzhou Mu2    Bolei Zhou1
*Equal contribution
We present Ctrl-X, a simple training-free and guidance-free framework for text-to-image (T2I) generation with structure and appearance control. Given user-provided structure and appearance images, Ctrl-X designs feedforward structure control to enable structure alignment with the structure image and semantic-aware appearance transfer to facilitate the appearance transfer from the appearance image. Ctrl-X supports novel structure control with arbitrary condition images of any modality, is significantly faster than prior training-free appearance transfer methods, and provides instant plug-and-play to any T2I and text-to-video (T2V) diffusion model.
How does it work?   Given clean structure and appearance latents, we first obtain noised structure and appearance latents via the diffusion forward process, then extracting their U-Net features from a pretrained T2I diffusion model. When denoising the output latent, we inject convolution and self-attention features from the structure latent and leverage self-attention correspondence to transfer spatially-aware appearance statistics from the appearance latent to achieve structure and appearance control. We name our method "Ctrl-X" because we reformulate the controllable generation problem by 'cutting' (and 'pasting') structure preservation and semantic-aware stylization together.
Results: Structure and appearance control
Results of training-free and guidance-free T2I diffusion with structure and appearance control, where Ctrl-X supports a diverse variety of structure images, including natural images, ControlNet-supported conditions (e.g., canny maps, normal maps), and in-the-wild conditions (e.g., wireframes, 3D meshes). The base model here is Stable Diffusion XL v1.0.
Results: Prompt-driven conditional generation
Ctrl-X also supports prompt-driven conditional generation, where it generates an output image complying with the given text prompt while aligning with the structure of the structure image. Ctrl-X continues to support any structure image/condition type here as well. The base model here is Stable Diffusion XL v1.0.
Results: Extension to video generation
We can directly apply Ctrl-X to text-to-video (T2V) models. We show results of AnimateDiff v1.5.3 (with base model Realistic Vision v5.1) here.
    title = {Ctrl-X: Controlling Structure and Appearance for Text-To-Image Generation Without Guidance}, 
    author = {Lin, {Kuan Heng} and Mo, Sicheng and Klingher, Ben and Mu, Fangzhou and Zhou, Bolei},
    year = {2024},
    eprint = {2406.07540},
    archivePrefix = {arXiv},
    primaryClass = {cs.CV}
Related Work
Sicheng Mo, Fangzhou Mu, Kuan Heng Lin, Yanli Liu, Bochen Guan, Yin Li, Bolei Zhou. FreeControl: Training-Free Spatial Control of Any Text-to-Image Diffusion Model with Any Condition. CVPR 2024.
Comment: Training-free conditional generation by guidance in diffusion U-Net subspaces for structure control and appearance regularization.
Yuval Alaluf, Daniel Garibi, Or Patashnik, Hadar Averbuch-Elor, Daniel Cohen-Or. Cross-Image Attention for Zero-Shot Appearance Transfer. SIGGRAPH 2024.
Comment: Guidance-free appearance transfer to natural images with self-attention key + value swaps via cross-image correspondence.