Stipple Placement using Distance in a Weighted Graph

We present a stipple placement method which provides extra emphasis to image features, especially edges. Our algorithm transforms an image into a regular graph, with edge weights given by the local gradient magnitude of the input image. Then, a variant of Disjkstra’s algorithm is used to place stipples: new stipples are placed along the frontier, which tends to be aligned with image edges. The resulting stipple distribution approximates a blue noise distribution, but emphasizes edges from the input image. We also show how irregular mosaics can be organized and the mosaic tiles shaped using the same underlying mechanism.