Kin S. Yen

Testing and Performance Evaluation of Fixed Terrestrial Three-Dimensional Laser Scanning Systems for Highway Applications

In many three-dimensional (3-D) laser scanner applications, high relative precision (relative dimensions within the registered point cloud) is sufficient; in contrast, highway infrastructure (HI) applications require good relative precision and high absolute accuracy. Thus, precise and robust georeferencing is critical, and robust work flows are needed to reduce the likelihood and impact of human errors. HI applications have a fairly unique combination of challenges, including longer-range requirements, long linear geometry for complete jobs, tall structures, and dark pavement scanned at a high incidence angle. These factors motivate standardized protocols and metrics to characterize and evaluate scanner performance and to develop confidence limits for the scanner data in such applications. The primary contribution in this study is a set of standard test protocols for the characterization and evaluation of 3-D laser scanner performance that users can conduct in easily accessible facilities. These evaluations focus on issues significant in HI survey applications, work flows, and data flows. An example performance evaluation is provided for several commercially available 3-D laser scanners. This study provides the needed scientific basis for data-driven deployment of this valuable measurement tool in HI applications. It also provides recommendations and guidelines that will promote consistent and correct use of 3-D laser scanners. The guidelines clarify the common limitations of 3-D laser scanners and recommend mitigation methods; this information will help engineers and surveyors to select the right scanner and determine optimum scanning settings for highway applications.

Cost-Benefit Analysis of Mobile Terrestrial Laser Scanning Applications for Highway Infrastructure

This paper presents a cost-benefit analysis of mobile terrestrial laser scanning (MTLS), specifically in highway infrastructure (HI) applications using data and requirements from the western United States. MTLS can be used for rapid data collection in a digital point-cloud format. This data can then be analyzed for mapping and feature inventory in several applications including asset management, preservation, maintenance, and operational planning performed by State Department of Transportation agencies. In this paper, data and requirements related to some of the operations of Washington State Department of Transportation and the California Department of Transportation are used as the basis for this cost-benefit analysis.

Analysis of the Multipass Approach for Collection and Processing of Mobile Laser Scan Data

AbstractThe standard method in surveying practice for adjusting mobile terrestrial laser scan (MTLS) data to correct for global navigation satellite system (GNSS) positioning errors consists of pla...