EP018: Turning Digital Static Into Images With Diffusion

"Denoising Diffusion Probabilistic Models" by Jonathan Ho, Ajay Jain, and Pieter Abbeel demonstrates that diffusion probabilistic models can generate high-quality images, achieving results competitive with or better than other leading generative models like GANs.Key points from the paper include:• High-Quality Synthesis: The authors show that diffusion models, which operate by gradually adding Gaussian noise to data (forward process) and then learning to reverse this process (reverse process), can produce state-of-the-art image samples. They achieved a state-of-the-art FID score of 3.17 on the CIFAR10 dataset.• Theoretical Connections: The paper establishes a novel connection between diffusion models and denoising score matching with Langevin dynamics. They show that a specific parameterization of the diffusion model reveals this equivalence, providing a strong theoretical foundation for their approach.• Simplified Training Objective: The authors propose a simplified training objective where the model is trained to predict the noise (ϵ) added to the image, rather than the posterior mean. This simplified weighted variational bound was found to produce better sample quality than the standard objective.• Progressive Coding: The research suggests that diffusion models have an inductive bias that makes them excellent lossy compressors, with the sampling procedure acting as a form of progressive decoding similar to autoregressive models.