Energy-based Calibrated VAE with Test Time Free Lunch

In this paper, we propose a novel Energy-Calibrated Generative Model that utilizes a Conditional EBM for enhancing Variational Autoencoders (VAEs). VAEs are sampling efficient but often suffer from blurry generation results due to the lack of training in the generative direction. On the other hand, Energy-Based Models (EBMs) can generate high-quality samples but require expensive Markov Chain Monte Carlo (MCMC) sampling. To address these issues, we introduce a Conditional EBM for calibrating the generative direction during training, without requiring it for test time sampling. Our approach enables the generative model to be trained upon data and calibrated samples with adaptive weight, thereby enhancing efficiency and effectiveness without necessitating MCMC sampling in the inference phase. We also show that the proposed approach can be extended to calibrate normalizing flows and variational posterior. Moreover, we propose to apply the proposed method to zero-shot image restoration via neural transport prior and range-null theory. We demonstrate the effectiveness of the proposed method through extensive experiments in various applications, including image generation and zero-shot image restoration. Our method shows state-of-the-art performance over single-step non-adversarial generation.