How can I convert a raster image to a vector one?

I'd like to know if is it possible to convert a raster image to a vector one.

I have different file, that are prints from Autocad or other similar program, in .pdf or other image format file and I need to convert them in vector format or in DWG or DXF files in order to modify them in DS.

I konw that I can import the Image into my workspace and then I can draw new line over them, btu I don't like to much this way of works.

Thanks for your attention.

Best Regards

Pier Alessandro