An algorithm that simplifies the labor-intensive task of colorizing black-and-white motion pictures has been created at Hebrew University in Jerusalem. The algorithm lets simple scribbles accomplish what would otherwise demand exacting definition. "Our colorization algorithm does not require precise image segmentation or accurate region tracking," said Dani Lischinski, an assistant professor at the university's School of Computer Science and Engineering. Instead of precisely defining areas, as computer-generated techniques require, he said, the algorithm allows an artist simply scribble over areas with "crayons" of different colors. The algorithm then takes over, filling in the regions with the various colors and tracking them from frame to frame.