vesicles
Colonel
Looks like they are using the Velcro. Not sure how wound that is. Unless the shell was modified with the helmet bolted through.
Well, it looks like they have a frame, with all sides angled inward, built on the helmet. The bottom of the camera should have a protrusion that angles outward and should click into the frame on the helmet.
A typical camera tripod would have a similar two-piece device on the top to hold the camera in place. I used to have a two-piece GPS holder in my car with a similar design.