Mounted on underwater vehicles, forward looking sonars offer critical situational awareness to operators navigating the challenges of low-visibility environments. Whether employed for obstacle avoidance, navigation through turbid waters, or conducting detailed surveys and inspections, sonar provides real-time imaging capability which can significantly improve the safety and efficiency of subsea operations.
The raw data captured by multibeam imaging sonars is displayed as video-style imagery, which can be analyzed in real time or recorded for later review. Despite the undeniable advantages of utilizing sonar in subsea operations, the data collected does have limitations for certain applications. While excellent for live viewing and post-operation analysis the data captured is innately restricted to the sonar’s immediate field of view.
When the goal is to create detailed maps of larger underwater environments, additional processing known as ‘mosaicking’ is required. This is where Iqua Robotics’ SoundTiles technology makes its mark, transforming the capability of multibeam imaging sonar into powerful tool for underwater mapping.
MOSAICKING CHALLENGES
Traditional methods for constructing acoustic mosaics typically rely on the vehicle’s positioning system to determine the location at which each image was recorded and then use this information to place each image onto a map. However, this approach is constrained by the accuracy of the vehicle’s positioning system, often leading to less consistent acoustic maps.
Moreover, this reliance on positioning data also complicates the generation of mosaics for vertical surfaces or walls, which can otherwise be effectively rendered by aligning the images based on their content. Traditional image registration methods usually rely on identifying a series of common features in overlapping images to determine how they align.
However, when working with acoustic images, this process is prone to errors due to noise, variations in position, or changes in perspective. Without advanced processing methods, the resulting mosaics can present fragmented data that fails to convey the true nature of the surveyed area.
A NEW APPROACH
SoundTiles represents a significant advancement in underwater mapping, addressing the challenges of traditional mosaicking techniques when using raw sonar data for comprehensive environmental surveys. By leveraging advanced algorithms, the software creates high-resolution, seamless maps from multibeam imaging sonar data.
Pivotal to SoundTiles’ mapping capability is its innovative image registration algorithm, which operates without the need for positioning data (one of the key limitations in conventional mosaicking techniques) and without relying on feature-based image alignment. This allows for the creation of accurate, consistent mosaics from any compatible sonar data, making the software highly versatile and beneficial to a multitude of survey applications.
Once their data has been uploaded into the software, users are guided through the process by an advanced wizard tool. Beginning with the automated alignment of temporally consecutive sonar images, the software estimates the trajectory in which the images were captured.
This process is efficient, taking anywhere from seconds to only a few minutes depending on the computer’s processing capacity and the number of images. Based on this initial estimation, the software adds further image alignments of overlapping images, ensuring they fit together cohesively.
PRECISE RENDERING
To tackle potential disruptions caused by noise or distortions in the sonar data, SoundTiles offers several rendering options to address a variety of issues that might otherwise compromise the quality of the final mosaic. In most instances, particularly when the survey has produced high-quality data, the software can automatically generate a clear and accurate mosaic.
However, in some cases extra refinement may be required and additional tools are available within the software to help achieve optimum results. The software is supported by comprehensive user training, where operators will be provided with guidelines for best practice when collecting sonar data to help ensure the software can produce high quality mosaics.
The ability to create detailed underwater mosaics has transformative implications across various industries and research fields. SoundTiles is particularly impactful in subsea infrastructure inspection, where it enables operators to generate precise maps of underwater assets such as pipelines, cables, and mooring chains. These maps highlight areas of wear, damage, or potential failure, supporting more effective maintenance planning, reducing downtime, and lowering operational costs.
STREAMLINING WORKFLOWS
Traditional underwater mapping often requires multiple passes and extensive manual processing, but SoundTiles streamlines this workflow, and by following the guidelines for data collection and post processing, users can efficiently produce reliable underwater maps. This advancement improves planning by reducing uncertainty and minimizing risks, optimizes resources by eliminating the need for repeat surveys, and enhances safety by providing clear and accurate environmental understanding to prevent accidents and equipment damage.
The development of SoundTiles is a testament to the growing collaboration between hardware and software in underwater technology. While multibeam imaging sonar has long been a powerful tool for subsea operations, the addition of intelligent software solutions like SoundTiles expands its functionality and unlocks new possibilities for exploration and documentation.
This feature appeared in ON&T Magazine’s 2025 Special Edition, The Future of Ocean Technology, Vol. 5, to read more access the magazine here.
