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Explanation

This error message arises when the chessboard calibration trial does not contain sufficient frames of overlapping visibility of the chessboard in 3 or cameras throughout the trial. This prevents the camera system from being properly calibrated, as there is insufficient information to calculate the position and orientation of all cameras in the system in 3D space.

Possible Solutions

1. Reduce the Frame Grab Step
   If the chessboard was detected in too few overlapping frames between camera groupings to form a continuous volume, it may be possible to calibrate the system with a lower Frame Grab Step value. Lower the Frame Grab Step value and run the calibration again.
2. Collect a new calibration trial.
   If it is not possible to reduce the Frame Grab Step to increase the overlapping visibility of the chessboard, it will be required to record a new calibration trial. If the camera system has not been taken down or modified since the data were collected and the data were collected relatively recently, a new calibration trial can be recorded. When recording the new calibration trial(s), be sure to focus on achieving an overlap in visibility of the chessboard surface in 3 or more cameras throughout the trial, and ensure that all camera groupings are linked by this overlap.