The kernel of the project is the mapping program that creates a representation of an occupancy-based grid-map in dynamic addressable memory. This mapping program is to operate as transparently as possible. Ideally it would be able to obtain highly detailed spatial data without noticeable interference with the primary operation. The program intermittently tasks the robot for sensor data, which it processes and stores in memory. Other processes may utilize the spatial data by directly addressing the array in memory. Included in the project package is an accessory program to aid in trouble shooting and data evaluation. It is an optionally activated software module that creates a pop-up window.
The map display program is an X-windows based program to visually display the mapping data. The window’s main feature consists of a large drawing area that presents the matrix information. A simple representation of the X-windows interface is shown in Figure 2. It is a pixmap-based graphical representation of the occupancy grid. Embedded along the left and bottom edge are the perpendicular axes with grid scales. Additionally there is a legend in the drawing area describing the shading scheme.
The display program is dynamic and periodically refreshes the displayed map to represent the current status of the memory array. The window also contains a scrollbar to adjust the threshold values for the map grid cell colors. This will permit the setting of the classification criteria for the cells in the next refresh process. The map may be tuned using this control and that will allow the selection of probability parameters for other processes. A pull-down menu is available to perform program functions such as Maximize, Minimize and Exit. A brief Help pull-down is also available. It is brief due to the simple nature of this display module.
This display program will demonstrate the dynamic accessibility of the raw data. The map will automatically re-scale the display to reflect the adjustment of the map boundaries. It will demonstrate the incremental nature of this mapping method.