Just doing the same thing they do, basically. Have a tiny transducer "hit" the cheese and listen for echo back. Now, I don't think ultrasound would work (it's

Just doing the same thing they do, basically. Have a tiny transducer "hit" the cheese and listen for echo back. Now, I don't think ultrasound would work (it's a harder cheese than Swiss cheese), also the mechanical interface would be a complication (you can't gel the cheese). CT would work but be expensive But tiny percussions and analysis of echo/transmission delays would work in principle