Algorithm 1: Rules of line fitting

Input: $\left\{\mathrm{L}\right\}$, $\epsilon$, $\theta$ Output: { lineclasses } 1.foreach line ${\mathrm{L}}_{\mathrm{i}}$ in $\left\{\mathrm{L}\right\}$ do 2. initialize lineclass; 3. flag = false; 4. foreach lineclass in { lineclasses } 5.      if distance < $\epsilon$, angle < $\theta$ 6.           flag = true; 7.              calculate new start point and end point of new lineclass 8.           break; 9.      end 10.     if flag = false 11.        pushback lineclass into {lineclasses}; 12.      end 13.end 14.end