Leveraging high-resolution multibeam data to deliver 3D model with 99% automatic score
ID OCEAN is a survey company that specializes in conducting coastal surveys, specifically for ports and harbors. Its headquarters is based in La Reunion, where the company has been able to take advantage of the island's distinctive geography and survey waters as deep as 150m.
La Nouvelle Route du Littoral (NRL) is a major project in La Reunion island and the surrounding Indian Ocean. The project consists in building a new highway, at sea, on the outskirts of the northwest of the island. This project will offer an alternative to the current road which is often closed either due to rock fall or because it is submerged by the sea. 5.4km of this new highway is built on a bridge, and 6.7km on a dyke, which stands on breakwaters.
ID OCEAN has been one of the main survey contractors for NRL for the last 4 years, which is a testimony to their expertise.
The breakwaters consist of monolayer precast concrete armor units that need to be arranged in a specific pattern, with each unit having a certain number of contact points with adjacent units. During construction, inspections are required to ensure that each unit is placed correctly. Ongoing monitoring is also necessary to track any potential movement of the armor pieces caused by swell.
Previously, monitoring methods involved using subsea videos, which were costly, time-consuming, and imprecise. Multibeam bathymetric point-clouds were also used, but these could be challenging for non-experts to analyze.
Enter Sonic 2022
Steven Le Bars, co-founder of ID OCEAN, explains that the company developed an as-built digital twin algorithm called Seabim®, which "can extract the position of a large number of blocks, based on the geo-referenced point-cloud data delivered by the multibeam, all in an automatic way." He goes on to say that "Thanks to the high-quality bathymetric data delivered by the Sonic 2022, Seabim® returns information with a 99% automatic shape-matching score. This is an improvement from the 94-95% accuracy that we achieved with other multibeams ... Furthermore, by automating the inspection process, we are removing the risks associated with sending divers and streamlining access to information."
Le Bars explains that ID OCEAN acquired the Sonic 2022 at the end of 2020 with the goal of expanding globally and providing a comprehensive package that includes data acquisition combined with data processing using Seabim®. He notes that the company was looking for a multibeam that was lightweight, easy to mobilize and transport, and capable of delivering high-quality bathymetric data. According to Le Bars, "The better the data, the less time we have to spend cleaning it during post-processing, and the greater is the accuracy of the information provided by Seabim®."
“The Sonic 2022 was a good compromise between compact form factor, resolution, swath coverage and quality of data. We had experience with other small multibeams, but none delivered the resolution that we needed. The Sonic 2022 provides excellent data.”
ID OCEAN created a customized mounting that includes the IMU, along with cameras that can fit in the R2Sonic PeliCase™, which is very convenient for international projects. “We have also standardized and optimized the pole with the other sensors so that it only takes us an hour to mobilize the Sonic 2022,” says Le Bars.