98 research outputs found
Relating Objective and Subjective Performance Measures for AAM-based Visual Speech Synthesizers
We compare two approaches for synthesizing visual speech using Active Appearance Models (AAMs): one that utilizes acoustic features as input, and one that utilizes a phonetic transcription as input. Both synthesizers are trained using the same data and the performance is measured using both objective and subjective testing. We investigate the impact of likely sources of error in the synthesized visual speech by introducing typical errors into real visual speech sequences and subjectively measuring the perceived degradation. When only a small region (e.g. a single syllable) of ground-truth visual speech is incorrect we find that the subjective score for the entire sequence is subjectively lower than sequences generated by our synthesizers. This observation motivates further consideration of an often ignored issue, which is to what extent are subjective measures correlated with objective measures of performance? Significantly, we find that the most commonly used objective measures of performance are not necessarily the best indicator of viewer perception of quality. We empirically evaluate alternatives and show that the cost of a dynamic time warp of synthesized visual speech parameters to the respective ground-truth parameters is a better indicator of subjective quality
Modelling talking human faces
This thesis investigates a number of new approaches for visual speech
synthesis using data-driven methods to implement a talking face.
The main contributions in this thesis are the following. The accuracy
of shared Gaussian process latent variable model (SGPLVM)
built using the active appearance model (AAM) and relative spectral
transform-perceptual linear prediction (RASTAPLP) features is improved
by employing a more accurate AAM. This is the first study
to report that using a more accurate AAM improves the accuracy of
SGPLVM. Objective evaluation via reconstruction error is performed
to compare the proposed approach against previously existing methods.
In addition, it is shown experimentally that the accuracy of AAM
can be improved by using a larger number of landmarks and/or larger
number of samples in the training data.
The second research contribution is a new method for visual speech
synthesis utilising a fully Bayesian method namely the manifold relevance
determination (MRD) for modelling dynamical systems through
probabilistic non-linear dimensionality reduction. This is the first time
MRD was used in the context of generating talking faces from the
input speech signal. The expressive power of this model is in the ability
to consider non-linear mappings between audio and visual features
within a Bayesian approach. An efficient latent space has been learnt
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Abstract iv
using a fully Bayesian latent representation relying on conditional nonlinear
independence framework. In the SGPLVM the structure of the
latent space cannot be automatically estimated because of using a maximum
likelihood formulation. In contrast to SGPLVM the Bayesian approaches
allow the automatic determination of the dimensionality of the
latent spaces. The proposed method compares favourably against several
other state-of-the-art methods for visual speech generation, which
is shown in quantitative and qualitative evaluation on two different
datasets.
Finally, the possibility of incremental learning of AAM for inclusion
in the proposed MRD approach for visual speech generation is
investigated. The quantitative results demonstrate that using MRD in
conjunction with incremental AAMs produces only slightly less accurate
results than using batch methods. These results support a way of
training this kind of models on computers with limited resources, for
example in mobile computing.
Overall, this thesis proposes several improvements to the current
state-of-the-art in generating talking faces from speech signal leading
to perceptually more convincing results
TEXT-DRIVEN MOUTH ANIMATION FOR HUMAN COMPUTER INTERACTION WITH PERSONAL ASSISTANT
International audiencePersonal assistants are becoming more pervasive in our environments but still do not provide natural interactions. Their lack of realism in term of expressiveness and their lack of visual feedback can create frustrating experiences and make users lose patience. In this sense, we propose an end-to-end trainable neural architecture for text-driven 3D mouth animations. Previous works showed such architectures provide better realism and could open the door for integrated affective Human Computer Interface (HCI). Our study shows that such visual feedback improves users' comfort for 78% of the candidates significantly while slightly improving their time perception
Perceptually Valid Facial Expressions for Character-Based Applications
This paper addresses the problem of creating facial expression of mixed emotions in a perceptually valid way. The research has been done in the context of a âgame-likeâ health and education applications aimed at studying social competency and facial expression awareness in autistic children as well as native language learning, but the results can be applied to many other applications such as games with need for dynamic facial expressions or tools for automating the creation of facial animations. Most existing methods for creating facial expressions of mixed emotions use operations like averaging to create the combined effect of two universal emotions. Such methods may be mathematically justifiable but are not necessarily valid from a perceptual point of view. The research reported here starts by user experiments aiming at understanding how people combine facial actions to express mixed emotions, and how the viewers perceive a set of facial actions in terms of underlying emotions. Using the results of these experiments and a three-dimensional emotion model, we associate facial actions to dimensions and regions in the emotion space, and create a facial expression based on the location of the mixed emotion in the three-dimensional space. We call these regionalized facial actions âfacial expression units.
DualTalker: A Cross-Modal Dual Learning Approach for Speech-Driven 3D Facial Animation
In recent years, audio-driven 3D facial animation has gained significant
attention, particularly in applications such as virtual reality, gaming, and
video conferencing. However, accurately modeling the intricate and subtle
dynamics of facial expressions remains a challenge. Most existing studies
approach the facial animation task as a single regression problem, which often
fail to capture the intrinsic inter-modal relationship between speech signals
and 3D facial animation and overlook their inherent consistency. Moreover, due
to the limited availability of 3D-audio-visual datasets, approaches learning
with small-size samples have poor generalizability that decreases the
performance. To address these issues, in this study, we propose a cross-modal
dual-learning framework, termed DualTalker, aiming at improving data usage
efficiency as well as relating cross-modal dependencies. The framework is
trained jointly with the primary task (audio-driven facial animation) and its
dual task (lip reading) and shares common audio/motion encoder components. Our
joint training framework facilitates more efficient data usage by leveraging
information from both tasks and explicitly capitalizing on the complementary
relationship between facial motion and audio to improve performance.
Furthermore, we introduce an auxiliary cross-modal consistency loss to mitigate
the potential over-smoothing underlying the cross-modal complementary
representations, enhancing the mapping of subtle facial expression dynamics.
Through extensive experiments and a perceptual user study conducted on the VOCA
and BIWI datasets, we demonstrate that our approach outperforms current
state-of-the-art methods both qualitatively and quantitatively. We have made
our code and video demonstrations available at
https://github.com/sabrina-su/iadf.git
Facial Modelling and animation trends in the new millennium : a survey
M.Sc (Computer Science)Facial modelling and animation is considered one of the most challenging areas in the animation
world. Since Parke and Watersâs (1996) comprehensive book, no major work encompassing the entire
field of facial animation has been published. This thesis covers Parke and Watersâs work, while also
providing a survey of the developments in the field since 1996. The thesis describes, analyses, and
compares (where applicable) the existing techniques and practices used to produce the facial
animation. Where applicable, the related techniques are grouped in the same chapter and described in
a chronological fashion, outlining their differences, as well as their advantages and disadvantages.
The thesis is concluded by exploratory work towards a talking head for Northern Sotho. Facial
animation and lip synchronisation of a fragment of Northern Sotho is done by using software tools
primarily designed for English.Computin
A framework for automatic and perceptually valid facial expression generation
Facial expressions are facial movements reflecting the internal emotional states of a character or in response to social communications. Realistic facial animation should consider at least two factors: believable visual effect and valid facial movements. However, most research tends to separate these two issues. In this paper, we present a framework for generating 3D facial expressions considering both the visual the dynamics effect. A facial expression mapping approach based on local geometry encoding is proposed, which encodes deformation in the 1-ring vector. This method is capable of mapping subtle facial movements without considering those shape and topological constraints. Facial expression mapping is achieved through three steps: correspondence establishment, deviation transfer and movement mapping. Deviation is transferred to the conformal face space through minimizing the error function. This function is formed by the source neutral and the deformed face model related by those transformation matrices in 1-ring neighborhood. The transformation matrix in 1-ring neighborhood is independent of the face shape and the mesh topology. After the facial expression mapping, dynamic parameters are then integrated with facial expressions for generating valid facial expressions. The dynamic parameters were generated based on psychophysical methods. The efficiency and effectiveness of the proposed methods have been tested using various face models with different shapes and topological representations
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