A Baseline-Free Lamb Wave Damage Localization Method Based on Compressed Sensing

Algorithm 1

Construction method of sub-Nyquist sampling matrix.

	Initialize:
	int a: the length of original data
	int b: the number of sub-Nyquist sampling points.
	mat Φ: sub-Nyquist sampling matrix.
	Ensure: a > b
(1)	Φ ⟵ zeros (b, a) % initialize Φ as a b × a zero matrix.
(2)	array pset ⟵ randperm (a, b) % randperm(a, b) returns an array containing b unique integers selected randomly from 1 to a.
(3)	array pset ⟵ sort (pset) % sort the elements of pset.
(4)	for (row = 1 to b) do
(5)	col ⟵ pset [i]
(6)	Φ [row, col] ⟵ 1
(7)	end for
(8)	return Φ