A Fast Map Merging Algorithm in the Field of Multirobot SLAM

Algorithm 1

Calculation process of distance-map 𝑑𝑚𝑎𝑝_𝑐 in grid map.

Input:  the grid map 𝑚 and grid value 𝑐

Output:  distance-map 𝑑𝑚𝑎𝑝_𝑐

1  for 𝑦=0  to  𝑛+1 do

2    for 𝑥=0  to  𝑛+1 do

3      if 𝑚(𝑥,𝑦)==𝑐  then

4     𝑑𝑚𝑎𝑝_𝑐[𝑥][𝑦]=0;

5      else

6     𝑑𝑚𝑎𝑝_𝑐[𝑥][𝑦]=∞;

7      end

8    end

9   end

10   for  𝑦=1  to  𝑛 do

11    for  𝑥=1  to  𝑛 do

12      ℎ=min(𝑑𝑚𝑎𝑝_𝑐[𝑛−𝑥+1][𝑛−𝑦]+1,𝑑𝑚𝑎𝑝_𝑐[𝑛−𝑥][𝑛−𝑦+1]+1);

13       𝑑𝑚𝑎𝑝_𝑐[𝑛−𝑥][𝑛−𝑦]=min(𝑑𝑚𝑎𝑝_𝑐[𝑛−𝑥][𝑛−𝑦],ℎ);

14    end

15   end

16   for 𝑦=1  to  𝑛 do

17    for 𝑥=1  to  𝑛 do

18       ℎ=min(𝑑𝑚𝑎𝑝_𝑐[𝑥−1][𝑦]+1,𝑑𝑚𝑎𝑝_𝑐[𝑥][𝑦−1]+1);

19       𝑑𝑚𝑎𝑝_𝑐[𝑥][𝑦]=min(𝑑𝑚𝑎𝑝_𝑐[𝑥][𝑦],ℎ);

20    end

21   end

22  return 𝑑𝑚𝑎𝑝_𝑐;