Tham khảo tài liệu 'mechatronics for safety, security and dependability in a new era - arai and arai part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 224 We use the SAD Sum of Absolute Difference algorithm for the area-based stereo matching in order to extract disparity image Moon et al. 2002 . In this study the walls of buildings are extracted from the regions with a same value in the disparity image. The Building regions are extracted using the height information from the disparity information with a priori knowledge of the one-floor height of building. Vanishing Points A non-vertical skyline caused by the roof of a building can provide information on the relative orientation between the robot and the building. What is necessary for estimating the relative orientation is the vanishing point. We first calculate the vanishing points of the non-vertical skylines with the horizontal scene axis. And we estimate an angle between the image plane and the line from the camera center to a vanishing point which is parallel to the direction of a visible wall in the building. Corners of Buildings The boundary lines are the vertical skylines of buildings adjoining to the sky regions Katsura et al. 2003 . The boundary lines correspond to the comers of buildings on the given map. Figure 1 A boundary line and two vanishing points. Figure 1 shows an extraction result of a comer of building CB from a vertical skyline and two vanishing points VP1 and VP2 from two non-vertical skylines respectively. The vertical and nonvertical skylines are adjoining to the sky region at the top right of the image. ROUGH MAP Although an accurate map provides accurate and efficient localization it needs a lot of cost to build and update Tomono et al. 2001 . A solution to this problem would be to allow a map to be defined roughly since a rough map is much easier to build. The rough map is defined as a 2D segment-based map that contains approximate metric information about the poses and dimensions of buildings. It also has rough metric information about the distances and the relative directions between the buildings present in the environment. The .
