Abstraction is at the heart of sketching due to the simple and minimal nature
of line drawings. Abstraction entails identifying the essential visual
properties of an object or scene, which requires semantic understanding and
prior knowledge of high-level concepts. Abstract depictions are therefore
challenging for artists, and even more so for machines. We present an object
sketching method that can achieve different levels of abstraction, guided by
geometric and semantic simplifications. While sketch generation methods often
rely on explicit sketch datasets for training, we utilize the remarkable
ability of CLIP (Contrastive-Language-Image-Pretraining) to distill semantic
concepts from sketches and images alike. We define a sketch as a set of
B\'ezier curves and use a differentiable rasterizer to optimize the parameters
of the curves directly with respect to a CLIP-based perceptual loss. The
abstraction degree is controlled by varying the number of strokes. The
generated sketches demonstrate multiple levels of abstraction while maintaining
recognizability, underlying structure, and essential visual components of the
subject drawn.
Authors
Yael Vinker, Ehsan Pajouheshgar, Jessica Y. Bo, Roman Christian Bachmann, Amit Haim Bermano, Daniel Cohen-Or, Amir Zamir, Ariel Shamir