Automatic roller path tracking and mapping for pavement compaction using infrared thermography

Compaction is an important task in asphalt pavement construction. It ensures high quality of the pavement to provide required long-term performance. Intelligent compaction (IC) integrated with global positioning system (GPS) is an innovative technology to help control the compaction quality of asphalt pavement by continuously providing the operator with the roller's current position and the number of rolling passes. However, the high equipment cost and signal disturbance are two identified issues when adopting the GPS for position estimation. This paper proposed a thermal-based method for real-time roller path tracking and mapping in pavement compaction operations. In this method, first, the incremental roller motion between each two consecutive frames was jointly estimated via calculation of the roller's heading direction by exploiting the pavement boundary information and the roller's translation using the optical flow technique. Then, the accuracy of the estimated incremental motion was optimized by incorporation of the roller's lateral position estimated by a position optimization model proposed by the authors. Finally, the roller's global location was estimated by chaining frame-by-frame roller motions recursively. Both laboratory and field validations were conducted to examine the performance of the proposed method, leading to the maximum mean absolute errors along the lateral direction to be 5.2 mm and 3.3 cm, respectively, and the maximum cumulative error rates along the longitudinal direction to be 0.85% and 0.73%, respectively. The validation results signified the method's potential as a low-cost and applicable alternative to the GPS in the current IC technology for roller's position tracking and mapping.