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Hierarchical Quantized Autoencoders (arxiv.org)
6 points by dfwallace on Mar 5, 2020 | hide | past | pdf | discuss on HN

In plain words: Images are squeezed through stacked layers that snap each patch to one of a few reusable code words, with randomness added to keep the picture faithful. At very low bitrates it keeps faces and digits sharp and recognizable, where usual neural compressors blur what matters.

Abstract

Despite progress in training neural networks for lossy image compression, current approaches fail to maintain both perceptual quality and abstract features at very low bitrates. Encouraged by recent success in learning discrete representations with Vector Quantized Variational Autoencoders (VQ-VAEs), we motivate the use of a hierarchy of VQ-VAEs to attain high factors of compression. We show that the combination of stochastic quantization and hierarchical latent structure aids likelihood-based image compression. This leads us to introduce a novel objective for training hierarchical VQ-VAEs. Our resulting scheme produces a Markovian series of latent variables that reconstruct images of high-perceptual quality which retain semantically meaningful features. We provide qualitative and quantitative evaluations on the CelebA and MNIST datasets.

Will Williams, Sam Ringer, Tom Ash, John Hughes, David MacLeod, Jamie Dougherty
arXiv:2002.08111 · cs.LG, cs.CV, cs.NE, stat.ML · submitted Feb 19, 2020 · updated Oct 16, 2020
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