Evolutionary Reproduction of Dutch Masters: The Mondriaan and Escher Evolvers

Creative evolutionary systems are often concerned with producing images of high artistic quality. A key challenge to such a system is to be humancompetitive by producing the same quality. Then, mimicking existing human artists could be seen as a canonical benchmark, not unlike the Turing test for intelligence. This chapter discusses two applications aimed at evolving images in the styles of two well-known Dutch painters: Mondriaan and Escher. For both cases we have an evaluation criterion based on “style-fidelity” as perceived and judged by the users. In other words, here we have a target style, which makes the (subjective) selection less free than in applications solely aiming at nice images. Technically, the Mondriaan evolver is less difficult, given that his most popular style “simply” uses horizontal and vertical lines, and primary colours to fill the resulting rectangles. The Escher evolver project is more challenging. First, because Escher’s style is less simple to capture. Second, the system is tested in vivo, in a real museum, posing requirements on the interface. We describe how to meet the style challenge based on the mathematical system behind Escher’s tiling. Designing a suitable representation and the corresponding variation operators based on this system specifies an appropriate search space guaranteeing the Escher style to some extent and leaving enough freedom for the selection. As for the second objective, we describe two versions that differ in the way the images are presented to, respectively evaluated by the visitors. The experiences gained during a six-month exhibition period in the City Museum in The Hague, The Netherlands, are discussed from the visitors’ perspective as well as from the algorithmic point of view and are illustrated with some “evolved Escher’s”.