<https://forums.getpaint.net/topic/17805-tool-plugins/#comment-306350>
<http://schema.org/text>
"These techniques are really interesting! I hadn't read the papers before. \nSometimes I manually inpaint simple things by selecting the void, filling it with the average color of some small surrounding region, and then running a small-radius Gaussian blur over the void iteratively until it seems to have converged. This is roughly equivalent to solving the Laplace equation over that region with Dirichlet boundary conditions... it ensures that the levels are smooth over the inpainted region, but the solution doesn't really respect what's \"going on\" at the boundary. * \nThat's about all I can remember about partial differential equations, so understanding the one described in the first paper is a little tough. The most I can figure out is that, since the image will be constant at the steady-state solution (∂I/∂t = 0), the gradient of the Laplacian of the solution will be orthogonal (dot product of the two terms = 0) to the isophotes (curves of equal luminance). So the Laplacian of the intensity surface will be constant along the isophotes... but I'm having a tough time determining what exactly this means in terms of how it determines the structure of the final image... best guess is that it enforces constant \"sharpness\" along the isophotes, so that a crisp edge doesn't fade into a soft one or something. \n* Incidentally, it also happens to be one of the obscure cases where differences between \"true\" and \"triangular\" Gaussian blurs become apparent! "
<https://forums.getpaint.net/topic/17805-tool-plugins/?tab=comments#comment-306400>