This reminds me of Trigrad ('Tringle Gradient Image Compression'), which compresses images by sampling points (at locations biased by the results of sobel edge detection); de-compression is performed by delaunay triangulation, then colouring the triangles using some scheme (the 'nearest neighbour' scheme, which coloured each triangle in a single color, is most similar to this).<p><a href="https://ruarai.github.io/Trigrad/old.html" rel="nofollow">https://ruarai.github.io/Trigrad/old.html</a><p><a href="https://ruarai.github.io/Trigrad/" rel="nofollow">https://ruarai.github.io/Trigrad/</a><p><a href="https://news.ycombinator.com/item?id=9828962" rel="nofollow">https://news.ycombinator.com/item?id=9828962</a>