Research Article

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