lidaRtRee (version 4.0.8)

tree_matching: 3D matching of detected tree top positions with reference positions

Description

First computes a matching index for each potential pair associating a detected with a reference tree. This index is the 3D distance between detected and reference points, divided by a maximum matching distance set by user-defined parameters. Pairs with the lowest index are then iteratively associated.

Usage

tree_matching(lr, ld, delta_ground = 2.1, h_prec = 0.14, stat = TRUE)

Value

A data.frame with matched pairs (row of reference positions in first column, and row of detected positions in second column) and corresponding 3D distances

Arguments

lr

data.frame or matrix. 3D coordinates (X Y Height) of reference positions

ld

data.frame or matrix. 3D coordinates (X Y Height) of detected positions

delta_ground

numeric. buffer around trunk position : absolute value

h_prec

numeric. buffer around apex position : proportion of reference tree height

stat

boolean. should matching stats be computed

References

Monnet, J.-M. 2011. Using airborne laser scanning for mountain forests mapping: Support vector regression for stand parameters estimation and unsupervised training for treetop detection. Ph.D. thesis. University of Grenoble, France. pp. 53-55 https://theses.hal.science/tel-00652698/document

Monnet, J.-M., Mermin, E., Chanussot, J., Berger, F. 2010. Tree top detection using local maxima filtering: a parameter sensitivity analysis. Silvilaser 2010, the 10th International Conference on LiDAR Applications for Assessing Forest Ecosystems, September 14-17, Freiburg, Germany, 9 p. https://hal.science/hal-00523245/document

See Also

plot_matched, hist_detection

Examples

# create reference and detected trees
ref_trees <- cbind(c(1, 4, 3, 4, 2), c(1, 1, 2, 3, 4), c(15, 18, 20, 10, 11))
def_trees <- cbind(c(2, 2, 4, 4), c(1, 3, 4, 1), c(16, 19, 9, 15))
#
# match trees
match1 <- tree_matching(ref_trees, def_trees)
match2 <- tree_matching(ref_trees, def_trees, delta_ground = 2, h_prec = 0)
match1
match2

# 2D display of matching result
plot_matched(ref_trees, def_trees, match1, xlab = "X", ylab = "Y")
plot_matched(ref_trees, def_trees, match2, xlab = "X", ylab = "Y")