This project aims at introducing Augmented Reality into the park touring carts. The key question is simultaneous localization, including 3d coordinates and azimuth. Thus, the first solution goes for the ORB-SLAM, while the second goes for the integration of UWB and imu.
AR Cart AR Prototype Two Stereo Slam
Camera Selection: The D435i camera has two Infrared cameras, one RGB camera, and one Infrared projector together with a built-in imu. Thus it can support the binocular SLAM, and use the imu to calibrate the position.
As we are using this camera outdoors and the distance of the IR projection is limited, this projector is disabled.
SoftWare Framework: The UE4 can only run smoothly in the Windows environment, however, the SLAM map saving and reloading can only be executed in the Linux environment. Therefore, we use the WSL (Windows Subsystem for Linux) to run the ORB-SLAM2, and ROS as the bridge to transmit data.
At the hardware level, the D435i stereo cam only achieves a 60° horizontal viewing angle, thus there is a risk of failure in map building when moving around places with many tourists nearby. Meanwhile, at the software level, instead of the dense point clouds, ORB SLAM uses keyframes and sparse point clouds to store the map. The content of each keyframe is strongly disturbed by the changing weather and sunlight.
Tested message: On this cart, we put different numbers and types of cameras onto this cart, to test various kinds of SLAM, visual part and imu part, indoors and outdoors.