The Robot Artist
The Robot Artist is a 7-DoF robot arm developed in our laboratory. The high number of joints allows it to have enough flexibility to operate more like a human artist. At the end of the manipulator, the robot is equipped with a three-finger gripper actuated by a single motor. An acrylic clamp is stick to two fingers to help the gripper fetch brushes stably.
The Robot Artist is endowed with the ability to create colorful artworks using the visual feedback just like all human artists. An external camera is attached at the gripper of the Robot Artist. The eye-in-hand configuration gives the robot a precise view of the scene and allows it to monitor the mixing color at any time.
In the beginning of the painting, most artists do not directly focus on the details of the picture. Instead, they usually cover the canvas with an initial layer of paint, which serves as a base for subsequent layers. This technique can greatly facilitate the realization of finely balanced compositions, and accurate depictions of lightness and chromatic subtleties.
We introduce the idea to the Robot Artist by partitioning the input image into several segments having similiar colors and taking them as the underpainting layer.
Generally, most of the colors can be mixed using three primary colors (cyan, magenta, yellow) and black. But unlike printers, human cannot precisely determine how much a color is needed for obtaining a desired color, so they usually start mixing with the most similar one to the desired color. Later, they sequentially add the colors which can make current color look more alike.
Based on this strategy, the Robot Artist repeatedly mixes colors using five basic colors (three primary colors, black and white) until getting desired color. With this mechanism, it can mix a varity of different colors.
Once the underpainting is finished, the Robot Artist will repeatedly compare the picture drawn on the canvas with the original image and find out most different area. A set of hand-painted strokes is then generated using the technology of non-photorealistic rendering (NPR) and painted on the canvas to refine the artworks.