Algorithm 2: 2D Wall Lines Connection and Refining

Input: 2D Wall Lines in floor plane: $\mathbb{L}$ Angle threshold: ${\phi }_0$

Output: Connection vectors of 2D wall lines: $L$

1:  initialize: Random Select one line $L_0$ from $\mathbb{L}$ 2:  Remove $L_0$ from $\mathbb{L}$, and add $L_0$ to $L$ 3:  while $\mathbb{L}$ is not empty do 4:     for $i=1, i\le length\left(\mathbb{L}\right), i++$do 5:        For distance set $\mathbb{D}: {\mathbb{D}}_i= D_v\left(L_0, {\mathbb{L}}_i\right)$ 6:     end for 7:     Find line candidate $L_c$ referring to the minimum value in $\mathbb{D}$ 8:     Remove $L_c$ from $\mathbb{L}$, and add $L_c$ to $L$ 9:  end while 10: for $j=1, j\le length\left(L\right), j++$ do 11:    Calculate the angle between adjacent lines: $Ang=A\left(L_j,L_{j+1}\right)$ 12:     if $Ang< {\phi }_0$ then 13:       Extend lines to obtain intersection point 14:       Update the vertexes of $L_j,L_{j+1}$ 15:    else 16:       Add one new line between $L_j,L_{j+1}$ 17:    end if 18: end for 19: Return: $L$