High resolution optical imaging system development and testing of shallow water Lagrangian floats in a riverine salt wedge
Abstract
High resolution visual and bathymetric maps at centimeter scales are valuable data products for characterizing complex sites by providign quantitative information about the texture and shape of the seafloor. These data products are also important for assessing change and capturing small scale localized phenomena such as diffuse hydrothermal venting. This project will address three research the"mes related to data driven survey refinement, detecting near bottom fluid anomalies and measuring change between observations space"d in time. To improve data collection an adaptive survey methodology will be developed to generate survey patterns in real-time based on for navigation and classification approaches to determine survey paths and patterns that balance the collection of new data with reacquisition of previously visiting locations provide constraints that help improve the overall navigation solution. This will help ensure that areas of variable compexity are sufficiently sampled and that the resulting map products are robust to potential errors in direct navigation measurements. This project will also address improvements to a structured light imaging system that is capa"ble of sub-centimeter scale mapping and fluid detection. The effective range, calibration and data classifiction will be addressed t"o transition the laser imaging system to autonomous platforms operating at faster speeds and higher altitudes off of the seafloor. The improved laser system and survey design approach will be used to develop a change detection method to cmopare surveys taken at different times. This approach will also use a SLAM framework and seek to merge acoustic and photographic information to highlight areas of the seafloor that have been disturbed or changed in the intervening time interval. The mapping work in this project will be carried out in collaboration with the Ocean Exploration Trust and the University of Rhode Island (URI) Graduate School of Oceanography (GSO). Field work for the project will utilize the E/V Nautilus and Hercules remotely operated vehicle (ROV) system during annual field seasons. Data collectoin will be completed using an existing imaging and sonar system built and operated by C. Roman for the He"rcules vehicle. THe system will be modified over the course of the project to increase the effective acoustic and laser ranges, and" provide better camera resolution. An optional phase of the project will build and test a new independent system for the large diameter AUV program. A second portion of the project will involve the adaptation of an existing shallow water Lagrangian float for investigating salt wedges in river inlets. This portion of the project will make modifications to a current shallow water Lagrangian float system and complete field work to assess the ability of the float to characterize a salt wedge front and track water moving up a river. The floats will be made to operate in the transition region between oceanic and fresh water. Various depth control and profiling modes will be evaluated to allow the float to operate in areas of large density gradients and variable bathymetry. This research program will entail training opportunities for a post doctoral scholar and several graduate students specializing in marine autonomy and sensing.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 05, 2017
- Source ID
- N000141712467
Entities
People
- Christopher Roman
Organizations
- Office of Naval Research
- United States Navy
- University of Rhode Island