97 The second method is plagued by issues unique to acoustic sensing in the underwater environment, such as moving shadows, pulses echoing or reverberating, and low signal-to-noise ratios, which makes it very challenging to stitch together sonar images into a high-quality mosaic as if they were simply normal camera photographs. IQUA Robotics’ SoundTiles software generates sonar mosaics quite differently to both approaches, and it is enabling the creation of accurate underwater maps using FLSs. At the heart of the software is a pairwise image registration algorithm that does not require positioning information to function and builds consistent mosaics purely on sequences of images taken from any compatible sonar file format. It is empowering the use of smaller UUVs with lighter payload complements and lower-end navigation systems. Making SoundTiles SoundTiles and its core algorithm originated from a PhD thesis on FLS mosaic processing, researched and published at the University of Girona in Spain. Its development has since been led by a team under Natalia Hurtós, software product manager at IQUA. “High-quality mosaics are critical to ocean and waterway analysts across many industries for showing trustworthy maps and spatial arrangements of features across assets and areas important to them, and because by accurately aligning multiple close images across an underwater area, you can hugely improve the signal-to-noise ratio across your reconstruction of that area, compared with what you get in your initial, individual images,” Hurtós explains. “After receiving funding to turn the algorithm and workflow into a product, the technology was licensed to IQUA, being a spinout from the same university. We then formed a team in the company for developing SoundTiles further. “Testing and refining the algorithm took huge amounts of data. We started collecting data since my PhD days using sensors and tools at the University of Girona, and as soon as we began engineering the software at IQUA, we had different people and organisations knocking on our doors to offer sonar datasets that we could use for demonstrating and improving the system.” These offers ramped up and continued beyond the first official release of SoundTiles in 2020, enabling ongoing optimisation and patching of the software post-release, which has been particularly important for IQUA when updating the product for compatibility with new sonar file types. Naturally, further data has come to Hurtós’ team through IQUA’s own surveys, conducted for customers using its Sparus II or Girona 500 autonomous underwater vehicles (AUVs). “Since licensing the algorithm to IQUA, a lot of work has also gone into tailoring the user interface [UI] into something that customers could digest and get to grips with, with much owed to efforts in finding ideal tools and programming libraries to optimise that UI,” Hurtós says. Before 2020, IQUA’s own engineers had alpha-tested the UI for the first critiques of its usability, workflows and mosaic quality, which was soon followed by betatesting for early adopters to provide their own valuable feedback. Such suggestions are still collected today, and fed into the development roadmap that Hurtós and her team follow for future updates. Today, SoundTiles is compatible with FLSs from Blueprint Subsea, Kongsberg Discovery, Norbit, Sound Metrics, Teledyne Reson and Tritech, thereby covering most of the systems available to UUV manufacturers, and the list will continue to grow in future. IQUA Robotics SoundTiles | In operation Uncrewed Systems Technology | June/July 2024 Considerable software engineering has gone into optimising the steps by which SoundTiles creates mosaics and making its user interface easier to work with High-quality mosaics are critical to ocean and waterway analysts across many industries for showing trustworthy maps and spatial arrangements
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