pitfill_stonge2008 {lidR}

Pits and spikes filling

Description

Pits and spikes filling for raster. Typically used for post-processing CHM. This algorithm is from St-Onge 2008 (see reference).

Usage

pitfill_stonge2008(
  x,
  lap_size = 3L,
  thr_lap = 0.1,
  thr_spk = -0.1,
  med_size = 3L,
  dil_radius = 0L
)

Arguments

x

raster. SpatRaster, RasterLayer, stars.

lap_size

integer. Size of the Laplacian filter kernel (integer value, in pixels).

thr_lap

numeric. Threshold Laplacian value for detecting a cavity (all values above this value will be considered a cavity). A positive value.

thr_spk

numeric. Threshold Laplacian value for detecting a spike (all values below this value will be considered a spike). A negative value.

med_size

integer. Size of the median filter kernel (integer value, in pixels).

dil_radius

integer. Dilation radius (integer value, in pixels).

References

St-Onge, B., 2008. Methods for improving the quality of a true orthomosaic of Vexcel UltraCam images created using alidar digital surface model, Proceedings of the Silvilaser 2008, Edinburgh, 555-562. https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=81365288221f3ac34b51a82e2cfed8d58defb10e

Examples

LASfile <- system.file("extdata", "MixedConifer.laz", package="lidR")
las <- readLAS(LASfile)
chm <- rasterize_canopy(las, 0.5, dsmtin())
sto <- pitfill_stonge2008(chm)

#terra::plot(c(chm, sto), col = lidR::height.colors(25))