Algorithm 1 Fast strip clustering algorithm.

1:Initialize cluster set $C_1=\left\{{\mathbf{S}}_1\right\}$, $R=1$. 2:for$u=1$ to U do 3: for each ${\mathbf{S}}_i$ in column u do 4:  Calculate the distance $d_{i,C_r}$ from this strip to the last inserted strip in each cluster $C_r$, where $r\in \{1,...,R\}$. 5:  if $\underset{r}{min}{d}_{i,C_r}<d^{th}$ then 6:   Insert strip ${\mathbf{S}}_i$ into cluster $C_r$. 7:  else 8:   $R=R+1$, create a new cluster $C_R$. 9:   Insert strip ${\mathbf{S}}_i$ into the new cluster $C_R$. 10:  end if 11: end for 12:end for