A sketch interface for understanding hand-drawn route maps

Sketching as a communications tool is an important medium that can convey a large amount of information in a simple diagram. We are interested in using sketches of route maps as input to a mobile robot for easily communicating a desired path. Such a system should be portable and easy to use for the novice user. For this reason, we chose a handheld PDA (personal digital assistant) computer as our platform. We describe a sketch interface designed for this PDA platform that is intuitive and simple to use without the need for point and click menus. The interface captures the stroke marks of the user and intelligently interprets the marks as intended features of the route map. Adding and removing landmarks is accomplished by simply drawing or crossing them out. A single path is sketched through the field of landmarks. The route direction is designated by either the sketched order or by explicitly designating one path end as the starting point. Additional options for undoing operations and moving landmarks are also provided. Sound and color provide feedback on the recognition of landmarks. A TCP-IP communications system allows the sketched route map to be wirelessly input into the robot navigation system.; A user evaluation of the sketch interface was performed. Users were divided into two groups and performed similar tasks with different scenes. Few significant differences were found between the groups, and the interface was rated highly by both groups; each surveyed question rated an average of 4.2 or higher out of a possible 5 points. Student volunteers found the system as easy to use as pencil and paper by a two-to-one margin.