Improving the Safety and Efficiency of Roadway Maintenance Phase II: Developing a Vision Guidance System for the Robotic Roadway Message Painter

Repainting existing roadway markings (turn arrows, STOP messages, railroad crossings, etc.) is an important task for transportation maintenance organizations. MnDOT estimates that over 75% of symbol and message painting is the repainting of existing markings. It would be extremely valuable for an automated painting system to have a vision guidance capability whereby an existing mark could be repainted accurately with little operator input. In this project a vision system was developed that is capable of identifying existing painted pavement markings and determining their dimensions, location, and orientation. Techniques were also developed whereby this information could be used to determine the location of the marking in the workspace of a painting robot to enable it to accurately repaint the marking. The vehicle-mounted robotic painter is still being built and tested, so final test results will not be available until the vision system can be completely integrated with the painter, and the two can be tested together. The accuracy of the projection produced using the techniques developed in this project would suggest that the final system will be capable of repainting pavement markings almost exactly where they appear on the roadway. Expected benefits of the deployment of a vision-guided robotic painting device include improved operator safety, improved productivity, and improved flexibility in roadway marking and repainting operations. Eventual users of a device using this technology could be city, county, state, and federal government agencies and private companies or contractors.