As they drew, the artists’ individual strokes were recorded. Factors such as length, curvature, stylus pressure, stylus speed, and directionality were taken into account. The strokes were then divided into two groups – shading strokes and contour strokes. Contour strokes were further sub-divided into complex and simple strokes. The computer noted the order in which the strokes were drawn, too – different artists use different facial features as their starting, middle and end points.
Additionally, the computer model noted each artist’s distinctive tendencies to deviate from the geometry of the faces in the photos. Whether an intentional aspect of their style or simply a mistake, some of the artists repeatedly drew subjects’ eyes closer together than they were in the photos, or gave them squarer jawlines.
via Gizmag
