Inputs: CS matrix D, measurement , upward extending coefficient l, weighting value c, and
iterative number K, wavelet transform level J, =
Outputs: approximated signal
Initialize: = , = , k = 0, = {1,2,…, (= N/2J)}
While halting criterion false do
   (1) k = k +1
   (2)
   (3)
   (4) construct upside-down tree
     (i) =
   (5)
   (6)
   (7)
end while
return
Algorithm 1: Upside-down tree orthogonal matching pursuit.