Algorithm 1 L1-norm penalization for spectral reflectance reconstruction

1:Initialization: ${\mathbf{W}}^0,{\mathbf{Z}}^0,{\mathbf{T}}^0,k\leftarrow 0$ and $\mu \leftarrow 0.1$ 2:repeat 3: Update ${\mathbf{W}}^{k+1}$ based on Equation (14) 4: Update ${\mathbf{Z}}^{k+1}$ based on Equation (15) 5: Update ${\mathbf{T}}^{k+1}$ based on Equation (16) 6: $k\leftarrow k+1$ 7:until$\left|\right|{\mathbf{W}}^k|-|{\mathbf{W}}^{k-1}\left|\right|<\epsilon$ Output:$\mathbf{W}\leftarrow {\mathbf{W}}^k$