Set a minimum number of 3D points to use for measuring plane. The valid point means a 3D point that is included in the measurement area excluding the window mask and is on a plane. When the number of valid 3D points in the measurement area is lower than this value, a finding of a plane is failed. Set a value between 3 and 45888. By setting a small value to the parameter, it is easy to succeed a finding but measurement accuracy is likely to degrade.