Algorithm 2 Search for parallel straight edges

1:$d_{max}\left(px\right)=physicalmax\left(cm\right)\times {\displaystyle \frac{focal\left(px\right)}{depth\left(cm\right)}}$ 2:if $n\ge 2$ then 3:    Calculate distance $D_i$ for all $E_i$ from $(x_c,y_c)$ 4:    Sort $E_i$ by $D_i$ (ascending) 5:    for ${\theta }_{max}=min$ to $max$ do                                                ▹ user-defined min/max 6:        for $i=1$ to $n-1$ do 7:           for $j=i+1$ to n do 8:               $\mathsf{\Delta }\theta =|{\theta }_{E_i}-{\theta }_{E_j}|$ 9:               if $\mathsf{\Delta }\theta \le {\theta }_{max}$ then 10:                   Draw $line$$d_i$ between $E_i,E_j$ 11:                   Check $|{\theta }_{line}-{\theta }_i| \ge {\theta }_{diff\_min}$ 12:                   Check $d_i\le d_{max}$ 13:                   if suitable then 14:                       Break 15:                   else 16:                       $j=j+1$ 17:           if no suitable pair then 18:               $i=i+1$ 19:        if no suitable pair then 20:           ${\theta }_{max}={\theta }_{max}+step$                                                ▹ user-defined step 21:    if pair found then 22:        Optimize grasp position 23:    else 24:        Sort $E_i$ by length $l_{E_i}$ (descending) 25:        for $i=1$ to n do 26:           K = Project $(x_{E_i},y_{E_i})$ to other side of P 27:           Distance K to $(x_{E_i},y_{E_i})\le d_{max}$ 28:           if suitable then 29:               Break 30:           else 31:               $i=i+1$