Title
Motion Prediction Under Multimodality with Conditional Stochastic Networks.
Abstract
Given a visual history, multiple future outcomes for a video scene are equally probable, in other words, the distribution of future outcomes has multiple modes. Multimodality is notoriously hard to handle by standard regressors or classifiers: the former regress to the mean and the latter discretize a continuous high dimensional output space. In this work, we present stochastic neural network architectures that handle such multimodality through stochasticity: future trajectories of objects, body joints or frames are represented as deep, non-linear transformations of random (as opposed to deterministic) variables. Such random variables are sampled from simple Gaussian distributions whose means and variances are parametrized by the output of convolutional encoders over the visual history. We introduce novel convolutional architectures for predicting future body joint trajectories that outperform fully connected alternatives cite{DBLP:journals/corr/WalkerDGH16}. We introduce stochastic spatial transformers through optical flow warping for predicting future frames, which outperform their deterministic equivalents cite{DBLP:journals/corr/PatrauceanHC15}. Training stochastic networks involves an intractable marginalization over stochastic variables. We compare various training schemes that handle such marginalization through a) straightforward sampling from the prior, b) conditional variational autoencoders cite{NIPS2015_5775,DBLP:journals/corr/WalkerDGH16}, and, c) a proposed K-best-sample loss that penalizes the best under a fixed prediction budget. We show experimental results on object trajectory prediction, human body joint trajectory and video under varying future uncertainty, validating quantitatively and qualitatively our architectural choices and training schemes.
Year
Venue
Field
2017
arXiv: Computer Vision and Pattern Recognition
Random variable,Image warping,Pattern recognition,Computer science,Stochastic neural network,Gaussian,Artificial intelligence,Sampling (statistics),Encoder,Optical flow,Machine learning,Trajectory
DocType
Volume
Citations 
Journal
abs/1705.02082
0
PageRank 
References 
Authors
0.34
22
6
Name
Order
Citations
PageRank
Katerina Fragkiadaki142421.57
Jonathan Huang277747.66
Alexander A. Alemi3709.92
Sudheendra Vijayanarasimhan497243.15
Susanna Ricco51195.85
Rahul Sukthankar66137365.45