filters.smrf¶
Filter ground returns using the Simple Morphological Filter (SMRF) approach outlined in [Pingel2013].
Note
Our implmentation of SMRF is in an alpha state. We’d love to have you kick the tires and provide feedback, but do not plan on using this in production.
The current implementation of filters.smrf
differs slightly from the
original paper. We weren’t too happy with the performance of (our implementation
of) the inpainting routine, so we started exploring some other methods.
Some warts about the current implementation:
- It writes a bunch of intermediate/debugging outputs to the current directory while processing. This should be made optional and then eventually go away.
[Pingel2013] | Pingel, T.J., Clarke, K.C., McBride, W.A., 2013. An improved simple morphological filter for the terrain classification of airborne LIDAR data. ISPRS J. Photogramm. Remote Sens. 77, 21–30. |
Example¶
The sample pipeline below uses filters.smrf
to segment ground and non-ground
returns, writing only the ground returns to the output file.
{
"pipeline":[
"input.las",
{
"type":"filters.smrf",
"extract":true
},
"output.laz"
]
}
Options¶
- cell
- Cell size. [Default: 1.0]
- classify
- Apply classification labels (i.e., ground = 2)? [Default: true]
- cut
- Cut net size (
cut=0
skips the net cutting step). [Default: 0.0] - extract
- Extract ground returns (non-ground returns are cropped)? [Default: false]
- slope
- Slope (rise over run). [Default: 0.15]
- threshold
- Elevation threshold. [Default: 0.15]
- window
- Max window size. [Default: 21.0]