  The problem of deforming an artist-drawn caricature according to a given
normal face expression is of interest in applications such as social media,
animation and entertainment. This paper presents a solution to the problem,
with an emphasis on enhancing the ability to create desired expressions and
meanwhile preserve the identity exaggeration style of the caricature, which
imposes challenges due to the complicated nature of caricatures. The key of our
solution is a novel method to model caricature expression, which extends
traditional 3DMM representation to caricature domain. The method consists of
shape modelling and texture generation for caricatures. Geometric optimization
is developed to create identity-preserving blendshapes for reconstructing
accurate and stable geometric shape, and a conditional generative adversarial
network (cGAN) is designed for generating dynamic textures under target
expressions. The combination of both shape and texture components makes the
non-trivial expressions of a caricature be effectively defined by the extension
of the popular 3DMM representation and a caricature can thus be flexibly
deformed into arbitrary expressions with good results visually in both shape
and color spaces. The experiments demonstrate the effectiveness of the proposed
method.
