I don't know specs of the HERO4, but the GoPro HERO3 has a 170 degree view angle - so that 16 camera rig has a _significant_ overlap. I suspect you could generate both "adjacent camera" and "every second camera" stereoscopic pairs without too much difficulty, and you can probably even extract useable data out of the "every third camera" pairs and their ~30 degree view overlap. My guess is everything seen by that rig is viewed by 3 distinct pairs (a&a+1, a&a+3, and a&a+3), and that the entire scene from a 16 camera 170fov rig could be considered to have 16 a&a+1 pairs, 16 a&a+2 pairs and 16 a&a+3 pairs giving you three stereo views with different baselines for every point in the scene. I'm guessing there's a _lot_ of spatial information in there.