This is an image visualizing a discrete 2D signed distance field (SDF). The original represented shape (duck) is in grey. Crosses mark pixel centers where SDF values are stored. From each pixel center a circles expands that visualizes the value stored at the pixel. The radius represents magnitude, the color represents a sign (red is negative, inside the shape; green is positive, outside the shape). Unification of green areas define the set of points that are definitely outside the shape, the unification of red ones define the set of points that are definitely inside. We can see that although the SDF representation may be better than classical raster image at this resolution, with a limited number of pixels in the raster the image is still represented imperfectly, with areas that are neither green nor red, defining a set of points whose belonging to the shape is unknown and for which a separate algorithm has to be used to estimate this. The picture also shows how more pixels further away from the shape improve accuracy of the representation.
Own work
Drummyfish