NEXT face embedding demo

Start the demo with bokeh serve myapp.

TODOs

1. make the feature finding of the face local (see stsievert#1)
2. use webcam instead of file upload (see stsievert#2)

This will mean that

1. make the feature finding of the face local

   • Images will not have to uploaded to dropbox
   • Face++ API will not be used
   • embedding new images will be much quicker (no upload)

2. use webcam instead of file upload

   • can have live updates, not discrete updates
   • might change threat model?