- Get a nice resolution image to work with
- Open the image in Inkscape
- Path -> Trace Bitmap
- Play with settings here -- this really depends
- e.g. Brightness Cutoff .45 or 2 or 3 by color
- Click Start
- Ungroup (Ctrl-Shift-G) on the result
- Delete the white background and other imperfect traces
*. Ctrl-Shift-K to break apart the image if you want to fine tune it, sometimes black spot will show up, that's ok. (Ctrl-K to recombine)
*. I also use the Object "Difference" command to clip out unnecessary parts.