  Facial sketch synthesis (FSS) aims to generate a vivid sketch portrait from a
given facial photo. Existing FSS methods merely rely on 2D representations of
facial semantic or appearance. However, professional human artists usually use
outlines or shadings to covey 3D geometry. Thus facial 3D geometry (e.g. depth
map) is extremely important for FSS. Besides, different artists may use diverse
drawing techniques and create multiple styles of sketches; but the style is
globally consistent in a sketch. Inspired by such observations, in this paper,
we propose a novel Human-Inspired Dynamic Adaptation (HIDA) method. Specially,
we propose to dynamically modulate neuron activations based on a joint
consideration of both facial 3D geometry and 2D appearance, as well as globally
consistent style control. Besides, we use deformable convolutions at
coarse-scales to align deep features, for generating abstract and distinct
outlines. Experiments show that HIDA can generate high-quality sketches in
multiple styles, and significantly outperforms previous methods, over a large
range of challenging faces. Besides, HIDA allows precise style control of the
synthesized sketch, and generalizes well to natural scenes and other artistic
styles. Our code and results have been released online at:
https://github.com/AiArt-HDU/HIDA.
