Automated Localization and Classification of Expressway Pole-Like Road Facilities from Mobile Laser Scanning Data

Algorithm 1

Cylindrical growing algorithm.

	Input:
	Q1: pole trunk points in Slicek (=Sliceinitial)
	Q2: pole trunk points in Slicem (=Sliceinitial−1)
	Parameters:
	i: current slice
	Start:
	Initialize: i = k − 2
	Compute Ck and Rk of points in Q1
	Compute Cm and Rm of points in Q2
	Repeat
	(1) Find R = max(Rk; Rm)
	(2) Extract and count the number of points n in slice i where distance to is less than R + ∆
	(3)  if 0 <n < N
	(4)   Add these points to pole trunks (cluster T)
	(5)   i = i − 1
	(6)  else
	(7)   Add these points to pole trunks (cluster T)
	(8)   Compute center Ci and radius Ri of points in the current slice i
	(9)   i = i − 1
	(10)   k = m
	(11)   m = i + 1
	Until no points were found
	Output: T: pole trunk points.