论文标题
用分层经验贝叶斯概括变分的自动编码器
Generalizing Variational Autoencoders with Hierarchical Empirical Bayes
论文作者
论文摘要
通过使用简单的体系结构,不需要对超参数进行大量微调的简单体系结构,变化自动编码器(VAE)最近获得了作为数据生成模型的成功。但是,已知VAE会遭受过度验证,这可能导致无法逃脱局部最大值。这种现象被称为后倒塌,可防止学习数据的有意义的潜在编码。最近的方法通过确定性力矩匹配汇总的后验分布到骨料先验,从而减轻了这一问题。但是,放弃概率框架(因此依靠点估计值)都可以导致不连续的潜在空间并产生不现实的样本。在这里,我们提出了分层经验贝叶斯自动编码器(HEBAE),这是概率生成模型的计算稳定框架。我们的主要贡献是两个方面。首先,我们通过在编码分布上放置层次结构来取得收益,从而使我们能够在最小化重建损失函数和避免过度验证之间的权衡平衡。其次,我们表明,假设潜在空间中变量之间的一般依赖性结构会产生更好的收敛到平均场假设上,以改善后验推断。总体而言,与类似的VAE相比,HEBAE对广泛的高参数初始化更为强大。使用MNIST和Celeba的数据,我们说明了HEBAE根据FID得分生成更高质量样本的能力,而不是现有的基于自动编码器的方法。
Variational Autoencoders (VAEs) have experienced recent success as data-generating models by using simple architectures that do not require significant fine-tuning of hyperparameters. However, VAEs are known to suffer from over-regularization which can lead to failure to escape local maxima. This phenomenon, known as posterior collapse, prevents learning a meaningful latent encoding of the data. Recent methods have mitigated this issue by deterministically moment-matching an aggregated posterior distribution to an aggregate prior. However, abandoning a probabilistic framework (and thus relying on point estimates) can both lead to a discontinuous latent space and generate unrealistic samples. Here we present Hierarchical Empirical Bayes Autoencoder (HEBAE), a computationally stable framework for probabilistic generative models. Our key contributions are two-fold. First, we make gains by placing a hierarchical prior over the encoding distribution, enabling us to adaptively balance the trade-off between minimizing the reconstruction loss function and avoiding over-regularization. Second, we show that assuming a general dependency structure between variables in the latent space produces better convergence onto the mean-field assumption for improved posterior inference. Overall, HEBAE is more robust to a wide-range of hyperparameter initializations than an analogous VAE. Using data from MNIST and CelebA, we illustrate the ability of HEBAE to generate higher quality samples based on FID score than existing autoencoder-based approaches.