13,043 research outputs found
Generating 3D faces using Convolutional Mesh Autoencoders
Learned 3D representations of human faces are useful for computer vision
problems such as 3D face tracking and reconstruction from images, as well as
graphics applications such as character generation and animation. Traditional
models learn a latent representation of a face using linear subspaces or
higher-order tensor generalizations. Due to this linearity, they can not
capture extreme deformations and non-linear expressions. To address this, we
introduce a versatile model that learns a non-linear representation of a face
using spectral convolutions on a mesh surface. We introduce mesh sampling
operations that enable a hierarchical mesh representation that captures
non-linear variations in shape and expression at multiple scales within the
model. In a variational setting, our model samples diverse realistic 3D faces
from a multivariate Gaussian distribution. Our training data consists of 20,466
meshes of extreme expressions captured over 12 different subjects. Despite
limited training data, our trained model outperforms state-of-the-art face
models with 50% lower reconstruction error, while using 75% fewer parameters.
We also show that, replacing the expression space of an existing
state-of-the-art face model with our autoencoder, achieves a lower
reconstruction error. Our data, model and code are available at
http://github.com/anuragranj/com
Self-Supervised Feature Learning by Learning to Spot Artifacts
We introduce a novel self-supervised learning method based on adversarial
training. Our objective is to train a discriminator network to distinguish real
images from images with synthetic artifacts, and then to extract features from
its intermediate layers that can be transferred to other data domains and
tasks. To generate images with artifacts, we pre-train a high-capacity
autoencoder and then we use a damage and repair strategy: First, we freeze the
autoencoder and damage the output of the encoder by randomly dropping its
entries. Second, we augment the decoder with a repair network, and train it in
an adversarial manner against the discriminator. The repair network helps
generate more realistic images by inpainting the dropped feature entries. To
make the discriminator focus on the artifacts, we also make it predict what
entries in the feature were dropped. We demonstrate experimentally that
features learned by creating and spotting artifacts achieve state of the art
performance in several benchmarks.Comment: CVPR 2018 (spotlight
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