Sensing Buried Items

I remember an agricultural problem where we needed to sense buried cables in sandy soil.  Recall there were easy methods to sense them,  not sure how this differs, but might be used in conjunction with other methods. Perhaps determining density of roots.    Other apps for buried objects in granular matter.

Slender Robotic Finger Senses Buried Items

MIT News, Daniel Ackerman, May 26, 2021

Massachusetts Institute of Technology (MIT) researchers have developed a slender robot finger with a sharp tip and tactile sensing capabilities that can help identify buried objects. Dubbed "Digger Finger," the robot can sense the shape of items submerged within granular materials like sand or rice. The researchers adapted their GelSight tactile sensor for the Digger Finger, and added vibration to make it easier for the robot to clear jams in the granular media that occur when particles lock together. MIT’s Radhen Patel said the Digger Finger's motion pattern must be adjusted based on the type of media in which it is searching, and the size and shape of its grains. MIT’s Edward Adelson said the Digger Finger “would be helpful if you’re trying to find and disable buried bombs, for example.”