[Cause]
The number of 3-dimensional points within the measurement area is at or below the threshold. Possible causes are:
1. The location or size of the measured area is incorrect.
2. There is little 3-dimensional map data.
3. The threshold for the number of 3-dimensional points is incorrect.
[Countermeasure]
For their respective reasons, the response is as follows:
1. Set the measurement region again.
2. Parameters for adjusting 3-D wide-area sensors.
3. Adjust [Minimum valid score].