We are looking for a 3-D scanner for a project which is mounted at a distribution center where trucks are monitored. The trucks are viewed from the top and the goal is to estimate the 3-D pose of the truck. We tried with the ZED stereo camera first, but they are terrible in long range accuracy. I'm looking now for suggestions for stereo cameras that can perform well at a longer range, around 15 meters at an accuracy of +/- 5 cm in the pose. Other options include lidars, but it would be great if the community can help us choose the model that can fit this requirement.
Stereo cameras perform well at short distances, indeed: when using binocular vision, it is much harder to determine whether the object is, say, 50 meters away or 50.1 meters away, than to know whether it's 1 meter away or 1.1 meter away, despite the difference of 10 cm. in both cases. Here's a diagram which may help; the bigger the difference between α1 and α2, the easier it is to determine the distance Δ1.
In order to make it easier, you should increase the distance between the “eyes.”
In other words, instead of using a stereo camera, where the distance between the sensors is usually just a few centimeters, you can use two ordinary cameras put at a distance of a few meters from each other.
Then, you can use, for instance, OpenCV in order to create a 3D scene. The terms you may look at are disparity map and 3D reconstruction.