In May 2011, Trimetari successfully completed a laser scanning project for a road in St. Petersburg. The client for this project was a design organization that utilizes modern design methods. The purpose of the project was to conduct a road surface repair using automated construction equipment control systems (ASUST). This specific requirement led to the selection of laser scanning as the preferred method for conducting the surveys.

 

Привзяка к точкам планово-высотного обоснования.A 1 km section of the road, including the road surface, curbstones, sidewalks, and intersections within the laser scanner’s range, was scanned during a 12-hour fieldwork session. The tie-in to survey control points was achieved using a total station instrument and the method of reciprocal observations with special targets. The post-processing of the acquired data involved data registration (alignment), noise removal, decimation, and exporting as a point cloud. Subsequently, the designers worked with the point cloud model. Since the traffic flow was not disrupted during the survey, the passing vehicles left traces on the resulting point cloud.

Участок дороги. Хорошо читаются дефекты покрытия.

This required additional efforts during the office processing stage to remove all points belonging to vehicles. Decimation was applied to achieve a uniform point density in the final point cloud. The polar measurement principle resulted in non-uniform point density distribution, with higher density near the instrument setup point and decreasing density further away from the scanner. Decimation helped optimize detail and file size, ensuring consistent point spacing throughout the surveyed section. Overall, the data processing actions were relatively straightforward and amenable to automation.

Крышка канализационного колодца на облаке точек.

The completed project demonstrated the effectiveness of terrestrial laser scanning for road surveys. Firstly, the non-contact measurement principle ensured safety, as conducting measurements with optical instruments (total stations) and placing targets on the roadway can be hazardous. Secondly, the scanning method significantly increased the level of detail, allowing for the creation of a highly detailed (down to centimeter-level) digital model of the road surface in polygonal form. Lastly, the fieldwork phase was conducted efficiently, with an average of one working day required to survey a 1 km section of an average road. The measurement accuracy remained within 1 cm of the planned survey control.