This is short overview of research paper. We present a practical algorithm for the automatic generation of a map that describes the operation environment of an indoor mobile service robot. The input is a CAD description of a building consisting of line segments that represent the walls. The algorithm is based on the exact cell decomposition obtained when these segments are extended to infinite lines, resulting in a line arrangement. The cells are represented by nodes in a connectivity graph. The map consists of the connectivity graph and additional environmental information that is calculated for each cell. The method takes into account both the path planning and position verification requirements of the robot and has been implemented.

1. Exact Cell Decomposition of
Arrangements used for Path
Planning in Robotics
Nora H. Sleumer / Nadine Tschichold-Gurman
Institute of Theoretical Computer Science
Institute of Robotics
Swiss Federal Institute of Technology
Zurich, Switzerland

2. Abstract
We present a practical algorithm for the automatic generation of a
map that describes the operation environment of an indoor mobile
service robot. The input is a CAD description of a building
consisting of line segments that represent the walls. The algorithm
is based on the exact cell decomposition obtained when these
segments are extended to infinite lines, resulting in a line
arrangement. The cells are represented by nodes in a connectivity
graph. The map consists of the connectivity graph and additional
environmental information that is calculated for each cell. The
method takes into account both the path planning and position
verification requirements of the robot and has been implemented.

3. Problem Statement
A CAD representation of a building defined by 39 line segments representing the
walls. The robot A moves in the white workspace outlined by grey obstacles.

4. Existing Solutions
RoadMap(Visibility Graphs)
Approximate Cell Decomposition

5. Existing Solution
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Exact Cell decomposition

6. The Arrangement Method
The 39 line segments (walls) result in an arrangement of 26
lines that decompose the free space into 76 cells.

7. Algorithm Steps
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Extend the line segments representing the
walls to lines.
Compute the arrangement and store in an
appropriate data structure
Merge the cells that are split unnecessarily
Calculate the environmental information for
each cell

9. Final Output
Arrangement decomposition with corresponding graph after
cell merging. The number of cells inside the building has been
reduced from 76 to 39.

10. Experimental Results

11. Questions ???