Non-linear blending techniques can be incorporated to handle more exaggerated facial expressions by introducing more complex relationships between the blendshapes and expression coefficients. Some ways to incorporate non-linear blending techniques include:
Non-linear Weighting Functions: Instead of linearly interpolating between blendshapes based on expression coefficients, non-linear weighting functions can be used to assign varying degrees of influence to each blendshape. Functions like sigmoid, exponential, or polynomial functions can introduce non-linearities in the blending process.
Piecewise Blending: Dividing the range of expression coefficients into segments and applying different blending functions to each segment can allow for non-linear transformations in specific regions of the expression space. This approach can handle exaggerated expressions more effectively by focusing on critical areas of the face.
Deep Learning Models: Utilizing deep learning models, such as neural networks, can learn complex non-linear mappings between expression coefficients and blendshapes. These models can capture intricate relationships and nuances in facial expressions that may not be adequately represented by linear blending.
The potential limitations of the linear blending approach used in this work include:
Limited Expressiveness: Linear blending may not capture the full range of facial expressions and deformations, especially when dealing with exaggerated or extreme expressions. Non-linear blending can provide more flexibility in representing these complex variations.
Artifacts and Discontinuities: Linear blending may lead to artifacts or discontinuities in the animation when transitioning between blendshapes, particularly in regions where non-linear deformations are required. Non-linear blending can smooth out these transitions and improve the overall visual quality.
Difficulty in Fine Detail Representation: Linear blending may struggle to represent fine details and subtle nuances in facial expressions, as it relies on a simple linear combination of blendshapes. Non-linear techniques can better capture these intricate details and improve the fidelity of the animation.
By incorporating non-linear blending techniques, the representation of facial expressions can be enhanced to handle more exaggerated deformations and improve the overall realism of the avatar animations.