3D face reconstruction and facial expression analytics using 3D facial data are new
and hot research topics in computer graphics and computer vision. In this proposal, we first
review the background knowledge for emotion analytics using 3D morphable face model, including
geometry feature-based methods, statistic model-based methods and more advanced
deep learning-bade methods. Then, we introduce a novel 3D face modeling and reconstruction
solution that robustly and accurately acquires 3D face models from a couple of images
captured by a single smartphone camera. Two selfie photos of a subject taken from the
front and side are used to guide our Non-Negative Matrix Factorization (NMF) induced
part-based face model to iteratively reconstruct an initial 3D face of the subject. Then, an
iterative detail updating method is applied to the initial generated 3D face to reconstruct
facial details through optimizing lighting parameters and local depths. Our iterative 3D
face reconstruction method permits fully automatic registration of a part-based face representation
to the acquired face data and the detailed 2D/3D features to build a high-quality
3D face model. The NMF part-based face representation learned from a 3D face database
facilitates effective global and adaptive local detail data fitting alternatively. Our system
is flexible and it allows users to conduct the capture in any uncontrolled environment. We
demonstrate the capability of our method by allowing users to capture and reconstruct their
3D faces by themselves.
Based on the 3D face model reconstruction, we can analyze the facial expression and
the related emotion in 3D space. We present a novel approach to analyze the facial expressions
from images and a quantitative information visualization scheme for exploring this
type of visual data. From the reconstructed result using NMF part-based morphable 3D face
model, basis parameters and a displacement map are extracted as features for facial emotion
analysis and visualization. Based upon the features, two Support Vector Regressions (SVRs)
are trained to determine the fuzzy Valence-Arousal (VA) values to quantify the emotions.
The continuously changing emotion status can be intuitively analyzed by visualizing the
VA values in VA-space. Our emotion analysis and visualization system, based on 3D NMF
morphable face model, detects expressions robustly from various head poses, face sizes and
lighting conditions, and is fully automatic to compute the VA values from images or a sequence
of video with various facial expressions. To evaluate our novel method, we test our
system on publicly available databases and evaluate the emotion analysis and visualization
results. We also apply our method to quantifying emotion changes during motivational interviews.
These experiments and applications demonstrate effectiveness and accuracy of
our method.
In order to improve the expression recognition accuracy, we present a facial expression
recognition approach with 3D Mesh Convolutional Neural Network (3DMCNN) and a visual
analytics guided 3DMCNN design and optimization scheme. The geometric properties of the
surface is computed using the 3D face model of a subject with facial expressions. Instead of
using regular Convolutional Neural Network (CNN) to learn intensities of the facial images,
we convolve the geometric properties on the surface of the 3D model using 3DMCNN. We
design a geodesic distance-based convolution method to overcome the difficulties raised from
the irregular sampling of the face surface mesh. We further present an interactive visual
analytics for the purpose of designing and modifying the networks to analyze the learned
features and cluster similar nodes in 3DMCNN. By removing low activity nodes in the network,
the performance of the network is greatly improved. We compare our method with the regular CNN-based method by interactively visualizing each layer of the networks and
analyze the effectiveness of our method by studying representative cases. Testing on public
datasets, our method achieves a higher recognition accuracy than traditional image-based
CNN and other 3D CNNs. The presented framework, including 3DMCNN and interactive
visual analytics of the CNN, can be extended to other applications
