extract .jpg from .pdf

I have some scanned books. One full page scanned image per pdf page.
Internal images stored in the pdf files in jpg ormat.

When I use the ImageMagic command

  convert foo.pdf foo.jpg

I believe that ImageMagick is rendering the pdf pages through
ghostscript. Resolution is coming out in 72x72 (pdf unit) resolution.

I suppose I could specify a higher sampling resolution, but I don't
want to do that.

I would like to extract the .jpg images directly, without going
through the internal ghostscript rendering process.

Q: How do I use ImageMagick to directly extract embedded .jpg images
from .pdf files?


Thanks,
Michael