Fig. 5
![Fig. 5](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs40648-020-00163-4/MediaObjects/40648_2020_163_Fig5_HTML.png)
Calibration targets placed on the floor (Top view). If four cameras are mounted on the robot, four square boards should be placed as the calibration targets on the floor so that at least two cameras can capture them
Calibration targets placed on the floor (Top view). If four cameras are mounted on the robot, four square boards should be placed as the calibration targets on the floor so that at least two cameras can capture them