Convert a raster image containing blobs to svg.
Assumptions:
- Single channel image
- Blobs are defined by given levels (e.g. 0=background 1-255=blobs)
- Blobs have genus-0 topologies (holes and enclosed shapes are ignored)
- Output blobs are single color
Requirements:
- numpy
- scipy
- opencv
- wand (optional, for saving a png copy)