

Depixelizing Pixel Art Android App - tosic
https://play.google.com/store/apps/details?id=de.theappguys.depixelizer

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tosic
We implemented the "Depixelizing Pixel Art" Algorithm by Kopf & Lischinski [1]
in Java and made an Android Pixel-Painter App out of it.

At some points we departed a bit from the original paper:

For the (approximate) Voronoi diagram we do not use a lookup table but look at
the orientation of each neighboring edge to determine the resulting pixel
shape because of that we have a special step that makes cell containing a
single pixel surrounded by another color a bit bigger, as otherwise single
pixel features appear too small (e.g. the dolphin from the original paper
would otherwise get tiny Howard-Moon-Style eyes) we use Catmull-Rom Splines
instead of B-Splines. As CR Splines go through their control points, we do not
need the correction step for spline positions mentioned in the paper.

We have not figured out how to add the shading for non-contour edges yet. SVG
(which is our target format) only allows Radial and Linear Gradients. We
thought about using Mesh Gradients or diffusion curves, but they are not part
of SVG yet... Also, the energy minimization step is still quite slow. We use
local relaxation as recommended in the paper, which works but is not very
fast. We want to try out some global methods that will hopefully speed the
process up.

What do you think?

[1] ([http://research.microsoft.com/en-
us/um/people/kopf/pixelart/](http://research.microsoft.com/en-
us/um/people/kopf/pixelart/))

