Algorithm 1 Classification algorithm

Input: ${\mathbf{A}}_{\mathbf{s}}$: smooth compressed dictionary. ${\mathit{y}}_{\mathit{i}}$: measurement value of image ${\mathit{x}}_i$ ${\mathrm{K}}_{\mathrm{s}}$: the number of iterations of the algorithm. Initialization: ${\mathit{\omega }}_i^0={\mathit{y}}_i,{\tilde{\mathbf{A}}}_i^0=\mathbf{\varnothing },{\mathsf{\Lambda }}_i^0=\mathbf{\varnothing }$ while $\mathbf{t}\le {\mathrm{K}}_{\mathrm{s}}$ do  ${\widetilde{c_1}}_i^t={argmax}_{c_1=1,\dots ,{\mathrm{C}}_1}\left|〈{\mathit{\omega }}_i^{t-1},{\mathit{a}\mathit{s}}_{c_1}〉\right|$;  ${\mathsf{\Lambda }}_i^t={\mathsf{\Lambda }}_i^{t-1}\cup {\widetilde{c_1}}_i^t$; ${\tilde{\mathbf{A}}}_i^t=\left[{\tilde{\mathit{A}}}_i^{t-1},{\mathit{a}\mathit{s}}_{{\widetilde{c_1}}_i^t}\right]$;  ${\tilde{\mathsf{\alpha }}}_i^t={\left({{\tilde{\mathbf{A}}}_i^t}^{\mathrm{T}}·{\tilde{\mathbf{A}}}_i^t\right)}^{-1}·{{\tilde{\mathbf{A}}}_i^t}^{\mathrm{T}}·{\mathit{y}}_{\mathit{i}}$;  ${\mathit{\omega }}_i^t={\mathit{y}}_i-{\tilde{\mathbf{A}}}_i^t·{\tilde{\mathsf{\alpha }}}_i^t;\mathrm{t}=\mathrm{t}+1$ end ${\mathrm{e}}_i={‖{\mathit{\omega }}_i^t‖}_2^2$ Output: ${\mathrm{e}}_i$: the residual energy of the $i$-th block’s image