@dillthekraut
Accelerometers give you rotational angles and acceleration along the vector. Even with 4 it will be very hard to get good tracking over space - angles of rotation will be great so if the object is attached to a singular point then this would work really well. Movement will be difficult.
If the screen moves freely accelerometers will be much less accurate and hard to combine than other methods that track from a fixed point (mocap or camera with marker). They measure acceleration and are often paired with gyroscopes. The combination can give you some useful data but even with a lot it will drift pretty fast. Some of this is from the hardware and interference and some of this is from the maths you need to do.
Things like skeleton suits that use accelerometers gain a lot of accuracy from inverse kinematics (IK). They are attached to a skeleton with defined angular relationships. The skeleton actually makes the maths harder but more reliable. You have some limits as to how things can move and with walking you get a reliable ground plane confirmation. This means that due to the fixed angular relationship between points multiple accelerometers can be used to confirm or reinforce the tracking. Even then the most common issues you see are drift. There have been a lot of accelerometer based mocap suits come and go over time. They are getting better but drift is something you see in all the early versions. Then after some r and d time eventually they solve the planar shift that lets you track people as they climb.
Without the skeleton (so tracking a single rigid object) you lose the IK solver that helps stabilise the movement model. With a single rigid body technically all your accelerometers will give you the same reading as it’s a single rigid body they are all attached to. Having more might help get rid of some interference but cannot add accuracy they way it does with IK.
Here is a reasonable article on the issues with this kind of tracking https://www.embedded.com/achieving-accurate-motion-tracking-in-consumer-portables.
If this worked well there would be a lot of cheap object tracking devices on the market. Although it is kind of possible there afaik no products that do this as it kind of doesn’t work. What you want to do is AR tracking and re-projection. Take a look at AR tracking methods. They almost all use cameras and different kinds of tracking.
Another thought is that you could stick and iPhone to the screen and try write an app that uses apples ARKit to output position and rotation data it will still drift and have issues though as you need to correlate the moving objects relative position with the projectors fixed position as well as its throw and lens distortion at different distances
This would be a cool problem to apply machine learning to. If you had great synchronised recordings of accelerometer movements and mocap data you could make a model that would likely do much better at rigid body tracking with accelerometers
Fred
