Generative Latent Flow

In this work, we propose the Generative Latent Flow (GLF), an algorithm for generative modeling of the data distribution. GLF uses an Auto-encoder (AE) to learn latent representations of the data, and a normalizing flow to map the distribution of the latent variables to that of simple i.i.d noise. In contrast to some other Auto-encoder based generative models, which use various regularizers that encourage the encoded latent distribution to match the prior distribution, our model explicitly constructs a mapping between these two distributions, leading to better density matching while avoiding over regularizing the latent variables. We compare our model with several related techniques, and show that it has many relative advantages including fast convergence, single stage training and minimal reconstruction trade-off. We also study the relationship between our model and its stochastic counterpart, and show that our model can be viewed as a vanishing noise limit of VAEs with flow prior. Quantitatively, under standardized evaluations, our method achieves state-of-the-art sample quality among AE based models on commonly used datasets, and is competitive with GANs' benchmarks.

[1]  Andriy Mnih,et al.  Resampled Priors for Variational Autoencoders , 2018, AISTATS.

[2]  Jeff Donahue,et al.  Large Scale GAN Training for High Fidelity Natural Image Synthesis , 2018, ICLR.

[3]  David P. Wipf,et al.  Diagnosing and Enhancing VAE Models , 2019, ICLR.

[4]  Andrew Zisserman,et al.  Very Deep Convolutional Networks for Large-Scale Image Recognition , 2014, ICLR.

[5]  Oriol Vinyals,et al.  Neural Discrete Representation Learning , 2017, NIPS.

[6]  Jaakko Lehtinen,et al.  Progressive Growing of GANs for Improved Quality, Stability, and Variation , 2017, ICLR.

[7]  Roland Vollgraf,et al.  Fashion-MNIST: a Novel Image Dataset for Benchmarking Machine Learning Algorithms , 2017, ArXiv.

[8]  Matthias Bethge,et al.  A note on the evaluation of generative models , 2015, ICLR.

[9]  Mohammad Havaei,et al.  Learnable Explicit Density for Continuous Latent Space and Variational Inference , 2017, ArXiv.

[10]  Jimmy Ba,et al.  Adam: A Method for Stochastic Optimization , 2014, ICLR.

[11]  Yuichi Yoshida,et al.  Spectral Normalization for Generative Adversarial Networks , 2018, ICLR.

[12]  Max Welling,et al.  Auto-Encoding Variational Bayes , 2013, ICLR.

[13]  Xiaogang Wang,et al.  Deep Learning Face Attributes in the Wild , 2014, 2015 IEEE International Conference on Computer Vision (ICCV).

[14]  David Pfau,et al.  Unrolled Generative Adversarial Networks , 2016, ICLR.

[15]  Olivier Bachem,et al.  Assessing Generative Models via Precision and Recall , 2018, NeurIPS.

[16]  Yoshua Bengio,et al.  NICE: Non-linear Independent Components Estimation , 2014, ICLR.

[17]  Soumith Chintala,et al.  Unsupervised Representation Learning with Deep Convolutional Generative Adversarial Networks , 2015, ICLR.

[18]  LinLin Shen,et al.  Deep Feature Consistent Variational Autoencoder , 2016, 2017 IEEE Winter Conference on Applications of Computer Vision (WACV).

[19]  Charles A. Sutton,et al.  VEEGAN: Reducing Mode Collapse in GANs using Implicit Variational Learning , 2017, NIPS.

[20]  Stefano Ermon,et al.  Flow-GAN: Bridging implicit and prescribed learning in generative models , 2017, ArXiv.

[21]  Alexei A. Efros,et al.  Unpaired Image-to-Image Translation Using Cycle-Consistent Adversarial Networks , 2017, 2017 IEEE International Conference on Computer Vision (ICCV).

[22]  Shakir Mohamed,et al.  Variational Inference with Normalizing Flows , 2015, ICML.

[23]  Jitendra Malik,et al.  Implicit Maximum Likelihood Estimation , 2018, ArXiv.

[24]  Koray Kavukcuoglu,et al.  Pixel Recurrent Neural Networks , 2016, ICML.

[25]  Max Welling,et al.  VAE with a VampPrior , 2017, AISTATS.

[26]  Patrick van der Smagt,et al.  Learning Hierarchical Priors in VAEs , 2019, NeurIPS.

[27]  Yingyu Liang,et al.  Generalization and Equilibrium in Generative Adversarial Nets (GANs) , 2017, ICML.

[28]  Andriy Mnih,et al.  Disentangling by Factorising , 2018, ICML.

[29]  Prafulla Dhariwal,et al.  Glow: Generative Flow with Invertible 1x1 Convolutions , 2018, NeurIPS.

[30]  Samy Bengio,et al.  Density estimation using Real NVP , 2016, ICLR.

[31]  Mario Lucic,et al.  Are GANs Created Equal? A Large-Scale Study , 2017, NeurIPS.

[32]  Navdeep Jaitly,et al.  Adversarial Autoencoders , 2015, ArXiv.

[33]  Daan Wierstra,et al.  Stochastic Backpropagation and Approximate Inference in Deep Generative Models , 2014, ICML.

[34]  David Lopez-Paz,et al.  Optimizing the Latent Space of Generative Networks , 2017, ICML.

[35]  Max Welling,et al.  Sylvester Normalizing Flows for Variational Inference , 2018, UAI.

[36]  Roger B. Grosse,et al.  Isolating Sources of Disentanglement in Variational Autoencoders , 2018, NeurIPS.

[37]  Li Fei-Fei,et al.  Perceptual Losses for Real-Time Style Transfer and Super-Resolution , 2016, ECCV.

[38]  Christian Ledig,et al.  Photo-Realistic Single Image Super-Resolution Using a Generative Adversarial Network , 2016, 2017 IEEE Conference on Computer Vision and Pattern Recognition (CVPR).

[39]  Ruslan Salakhutdinov,et al.  Importance Weighted Autoencoders , 2015, ICLR.

[40]  Iain Murray,et al.  Masked Autoregressive Flow for Density Estimation , 2017, NIPS.

[41]  Dumitru Erhan,et al.  Going deeper with convolutions , 2014, 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR).

[42]  Honglak Lee,et al.  Attribute2Image: Conditional Image Generation from Visual Attributes , 2015, ECCV.

[43]  Shakir Mohamed,et al.  Distribution Matching in Variational Inference , 2018, ArXiv.

[44]  Bernhard Schölkopf,et al.  A Kernel Method for the Two-Sample-Problem , 2006, NIPS.

[45]  Ian J. Goodfellow,et al.  NIPS 2016 Tutorial: Generative Adversarial Networks , 2016, ArXiv.

[46]  Sepp Hochreiter,et al.  GANs Trained by a Two Time-Scale Update Rule Converge to a Local Nash Equilibrium , 2017, NIPS.

[47]  Yoshua Bengio,et al.  Generative Adversarial Nets , 2014, NIPS.

[48]  Jitendra Malik,et al.  Non-Adversarial Image Synthesis With Generative Latent Nearest Neighbors , 2018, 2019 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR).

[49]  Yoshua Bengio,et al.  What regularized auto-encoders learn from the data-generating distribution , 2012, J. Mach. Learn. Res..