Flexible and cost-effective technology for streaming high-quality underwater videos and images has been developed by researchers at KAUST. The researchers improved the bandwidth to achieve better video quality.
Oceans are a huge part of our planet -- two-thirds of Earth is covered by oceans. The oceans are a major source of biodiversity, food and medicines. They also contain reserves of oil, gas and marine aggregates that could be used for industrial processes.
Wireless technologies can produce real-time video the potential to open the oceans for further exploration and monitoring. They will be useful for the inspection and maintenance of underwater pipelines, cables and offshore oil and gas fields where waters are too shallow for remotely operating vehicles and where it is too impractical and expensive to send a diver.
Current technologies already in use, like acoustic communications and low-frequency radio waves, are limited by narrow bandwidths and the requirement for large antennae and high-transmission powers. This makes them unsuitable for streaming good-quality, real-time video.
Researchers explored underwater wireless optical communication (UWOC) systems. UWOC systems consume less power and offer the higher bandwidths that are required for streaming live video.
"We first built the real-time video transmission system and then integrated it into a UWOC setup," said Ph.D. student Abdullah Al-Halafi. "Although the design and development of the system were very challenging, its ability to be programmed enabled us to reconfigure the system into several different arrangements."
To improve the accuracy of the detected signal, the researchers used a technique called quadrature amplitude modulation to increase the representation of information carried by the signal for a bandwidth. They compared it to phase-shift keying. This changes the phase of the carrier signal and optimizes the transmission for each configuration.
To check how the system is performing, the team developed an algorithm that measures the errors that occur during transmission called the bit error rate. By passing the signal through a five-meter trough that contains water of differing turbidity, they could test the quality of the video under different types of ocean water.
"Our system produced the highest-quality video streaming so far achieved in UWOC systems and provides a reconfigurable and cost-effective communications system for underwater live video streaming," said Al-Halafi. "It could lead to advances in underwater research and the discovery of new resources."
A paper on this research was published in the journal The Optical Society.