Vector Quantized Diffusion Model for Text-to-Image Synthesis

TL;DR

The paper introduces VQ-Diffusion, a novel text-to-image generation model that leverages vector quantization and diffusion processes to produce higher quality images more efficiently than previous methods.

Contribution

It proposes a new latent-space diffusion approach using VQ-VAE and a mask-and-replace strategy, significantly improving image quality and generation speed over existing models.

Findings

VQ-Diffusion outperforms autoregressive models in image quality.

The method handles complex scenes better than GAN-based approaches.

Generation speed is fifteen times faster with reparameterization.

Abstract

We present the vector quantized diffusion (VQ-Diffusion) model for text-to-image generation. This method is based on a vector quantized variational autoencoder (VQ-VAE) whose latent space is modeled by a conditional variant of the recently developed Denoising Diffusion Probabilistic Model (DDPM). We find that this latent-space method is well-suited for text-to-image generation tasks because it not only eliminates the unidirectional bias with existing methods but also allows us to incorporate a mask-and-replace diffusion strategy to avoid the accumulation of errors, which is a serious problem with existing methods. Our experiments show that the VQ-Diffusion produces significantly better text-to-image generation results when compared with conventional autoregressive (AR) models with similar numbers of parameters. Compared with previous GAN-based text-to-image methods, our VQ-Diffusion can handle more complex scenes and improve the synthesized image quality by a large margin. Finally, we show that the image generation computation in our method can be made highly efficient by reparameterization. With traditional AR methods, the text-to-image generation time increases linearly with the output image resolution and hence is quite time consuming even for normal size images. The VQ-Diffusion allows us to achieve a better trade-off between quality and speed. Our experiments indicate that the VQ-Diffusion model with the reparameterization is fifteen times faster than traditional AR methods while achieving a better image quality.