Resample
This command allows to keep points regularly spaced on cloud(s).
Requirements
Select at least one cloud and launch the command.
Set the value for Average distance. This value is used to define the size of the grid cells projected on the point cloud. In each cell, a small part of the surface is computed and the closest point to the surface is considered as the best one and is kept.
Locally, if the density of points is not sufficient to calculate a surface, the grid spacing is increased to an optional size that can be defined by the parameter Max distance.
Notes
If no Max distance size is set, the cells can grow to the size of the cloud itself.
To ensure a good result, if Max distance is used, it can't be lower than twice the Average distance.
Technical information
Comparison between Reduce and Resample:
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Reduce |
Resample |
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Reduction factor (ratio between the number of input points and output points) |
The reduction factor is "under control" and can be low. |
The reduction factor is not known in advance. |
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Noise measurement elimination |
No measurement noise removal. Points in low density areas are all preserved unlike the high density areas where points are primarily destroyed. |
If a maximum distance is fixed, the points in low density areas are destroyed, because they are suspected of being noisy points. |
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Point selection |
No point is "qualified". The processing is purely statistical. |
Each point is singly "qualified" to keep only the best ones. |