Optical Inspection Of Ports And Harbors: Laser-Line Sensor Model Applications In 2 And 3 Dimensions

There are 361 ports of interest to the US Coast Guard regarding homeland security issues. Speed and accuracy of inspections there for "foreign objects" is critical to maintaining the flow of commerce through these ports. A fusion of acoustic and optical imaging technologies has been implemented to rapidly locate anomalies acoustically and inspect them optically. Results of field tests are presented. Effective deployment of AUV- or ROV-mounted optical sensors to inspect ship hulls and port facilities will depend on accurate, real-time prediction of the sub-surface optical environment and upon accurate sensor models parameterized for the time and place of inspection. For bi-static laser-line scanner sensors such as the Real-time Ocean Bottom Optical Topographer (ROBOT), ambient light decreases the range to the inspection object (e.g. hull) for which laser-line contrast is adequate for ranging and imaging in 3-D. Reduced range implies narrower swaths and longer inspection times. A 2-D and 3-D hybrid marine optical model (HyMOM) of the environment beneath ships or adjacent to sea walls and pilings has been developed, applied and validated in eutrophic and mesotrophic settings, and a Monte Carlo sensor model of ROBOT has been developed. Both are discussed and combined to evaluate sensor performance in different environments. To provide the inherent optical properties needed to run such models, data from the Autonomous Marine Optical System (AMOS) were collected and transmitted back to the laboratory. Examples of AMOS results and model outputs are presented.