This is so cool. Awesome work!

I used a JS library a long time ago to make this, for taking a smartphone photo of a drawing and making it into an SVG on a JS-only web interface: http://jywarren.github.io/vectorcam

the new release of the library (https://github.com/jankovicsandras/imagetracerj) has more features but dunno if it has centerline tracing… still, could be interesting for potentially instantly converting a drawing into a cuttable SVG from a smartphone camera, which would be rad.