Open-source PixArt-δ image generator spits out high-resolution AI images in 0.5 seconds


Stable Diffusion may soon have some competition when it comes to open-source image generators. In its latest iteration, PixArt becomes faster and more accurate while maintaining a relatively high resolution.

In a paper, researchers from Huawei Noah’s Ark Lab, Dalian University of Technology, Tsinghua University, and Hugging Face presented PixArt-δ (Delta), an advanced text-to-image synthesis framework designed to compete with the Stable Diffusion family.

This model is a significant improvement over the previous PixArt-α (Alpha) model, which was already able to quickly generate images with a resolution of 1024 x 1024 pixels.

High-resolution image generation in half a second

PixArt-δ integrates the Latent Consistency Model (LCM) and ControlNet into the PixArt-α model, significantly accelerating inference speed. The model can generate high-quality images with a resolution of 1,024 x 1,024 pixels in just two to four steps in as little as 0.5 seconds, seven times faster than PixArt-α.



SDXL Turbo, introduced by Stability AI in November 2023, can generate images of 512 x 512 pixels in just one step, or about 0.2 seconds.

However, PixArt-δ’s results are higher resolution and seem more consistent compared to SDXL Turbo and a four-step variant of SDXL with LCM. The images appear to have fewer errors and the model follows the instructions more accurately.

Image: Chen et al.

The new PixArt model is designed to train efficiently on V100 GPUs with 32 GB of VRAM in less than a day. In addition, its 8-bit inference capability allows it to synthesize 1024-pixel images even on 8-GB GPUs, greatly improving its usability and accessibility.

More control over image generation

The integration of a ControlNet module into PixArt-δ allows finer control of text-to-image diffusion models using reference images. The researchers have introduced a novel ControlNet architecture specifically designed for transformer-based models that provide explicit controllability while maintaining high-quality image generation.

Image: Chen et al.

The researchers have published the weights for the ControlNet variant of PixArt-δ on Hugging Face. However, an online demo seems to be available only for PixArt-α with and without LCM.


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