How can I merge all the lidar readings into 1 point cloud?
- Find extrinsic between the sensors using a calibration target or any other methods.
- Now that you know the relative locations of the sensors, transform the points in each sensor to the first LiDAR coordinate(e.g top left LiDAR in your figure). All the points are merged into the first LiDAR coordinate now.
You need to learn 1. rigid transformation of 3d points, the transformation matrix 2. LiDAR extrinsic calibration.
2 could be difficult if the lidars do not have enough overlap or if you don't have the base knowledge. Request it to the maker if possible.
Not very accurate but ICP could be used to find out the extrinsic which can be found in a point cloud viewer like meshlab or cloud compare. Save scan from all the sensors and load it to the sw above. By aligning using ICP you will have the extrinsic. Save the found extrinsic and next time when you have new point cloud, just apply the same transformation. This could be used only when the LiDARs have enough overlap.