Adaptive networks 1 Adaptive perception 1 Condition 1 Constrained conditions 1 Face sketch synthesis 1 Facial components 1 Facial regions 1 History of engineering and technology 1 New benchmark 1 Unconstrained scenario 1 Unconstrained scenarios 1 Visual computing 1 article 1 ethnic group 1 face 1 feature extraction 1 feature learning (machine learning) 1 human 1 illumination 1 perception 1 synthesis 1