Hi,

Perhaps it could help you.
Vector graphic software like Inkscape, is able to digitalize bitmap pictures.
So, you can
- import your pdf file in Inkscape
- you have to ungroup your object (because Inkscape see in a pdf a group)
- select the picture
- use the function Path/vectorize bitmap
- use a single path option and validate
- you have now a bitmap and a vector object.
- delete the bitmap
- save your file as SVG file or pdf (this pdf will be a vector pdf)

Moi can import SVG files or pdf vector files.

Test it. It could be part of your need.