1,218 research outputs found
Dynamic Variational Autoencoders for Visual Process Modeling
This work studies the problem of modeling visual processes by leveraging deep
generative architectures for learning linear, Gaussian representations from
observed sequences. We propose a joint learning framework, combining a vector
autoregressive model and Variational Autoencoders. This results in an
architecture that allows Variational Autoencoders to simultaneously learn a
non-linear observation as well as a linear state model from sequences of
frames. We validate our approach on artificial sequences and dynamic textures
Biologically Inspired Dynamic Textures for Probing Motion Perception
Perception is often described as a predictive process based on an optimal
inference with respect to a generative model. We study here the principled
construction of a generative model specifically crafted to probe motion
perception. In that context, we first provide an axiomatic, biologically-driven
derivation of the model. This model synthesizes random dynamic textures which
are defined by stationary Gaussian distributions obtained by the random
aggregation of warped patterns. Importantly, we show that this model can
equivalently be described as a stochastic partial differential equation. Using
this characterization of motion in images, it allows us to recast motion-energy
models into a principled Bayesian inference framework. Finally, we apply these
textures in order to psychophysically probe speed perception in humans. In this
framework, while the likelihood is derived from the generative model, the prior
is estimated from the observed results and accounts for the perceptual bias in
a principled fashion.Comment: Twenty-ninth Annual Conference on Neural Information Processing
Systems (NIPS), Dec 2015, Montreal, Canad
Learning Dynamic Generator Model by Alternating Back-Propagation Through Time
This paper studies the dynamic generator model for spatial-temporal processes
such as dynamic textures and action sequences in video data. In this model,
each time frame of the video sequence is generated by a generator model, which
is a non-linear transformation of a latent state vector, where the non-linear
transformation is parametrized by a top-down neural network. The sequence of
latent state vectors follows a non-linear auto-regressive model, where the
state vector of the next frame is a non-linear transformation of the state
vector of the current frame as well as an independent noise vector that
provides randomness in the transition. The non-linear transformation of this
transition model can be parametrized by a feedforward neural network. We show
that this model can be learned by an alternating back-propagation through time
algorithm that iteratively samples the noise vectors and updates the parameters
in the transition model and the generator model. We show that our training
method can learn realistic models for dynamic textures and action patterns.Comment: 10 page
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