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Technology that combines sound and light to map the ocean

Stanford University engineers have developed a method to create images of underwater objects by combining sound and light, allowing for high-resolution ocean mapping.

An “optical-sound system locates underwater objects from the air” can be installed underneath drones to survey the ocean. This invention by a group of engineers, published in IEEE Access magazine, breaks the barriers that previous technologies have encountered.

Oceans cover about 70% of the Earth’s surface, however only a fraction of their depth is captured and mapped in high resolution.

The main reason is because sound waves pass from air to water, and vice versa, more than 99.9% of energy will be lost due to reflection phenomenon. Therefore, if the observing device uses sound waves, it consumes twice the energy when transmitting and receiving the signal, which means 99.9999% of the energy is reduced.

As for electromagnetic radiation waves like light, microwave and radar signals, water will absorb them. It is therefore also difficult for devices to use these waves to propagate from air to water. This could explain why sunlight cannot travel far under the ocean, and smartphones cannot be called underwater because telephone waves are a form of electromagnetic radiation.

According to SciTechDaily, the team removed those barriers with an innovation. The idea comes from envisioning a hybrid system of light and sound that could help survey the oceans from the air, detect shipwrecks and crashes, map ocean depths at speed and the same level of accuracy when performed on the ground.

“We have developed a system that is sensitive enough to compensate for the energy loss while still allowing the signal to detect and generate images,” said Associate Professor Amin Arbabian at Stanford Technical University, which led the study, identify.

The reflected ultrasonic waves are recorded by the transducers. Computer software assembles pieces of audio signals together and reconstructs a hologram of terrain features or underwater objects.

“Just as light is refracted or” broken “when passed from air to water or any denser medium, the ultrasound is refracted. Our image reconstruction algorithm corrects the correction. Fracturing occurs when ultrasonic waves travel backwards from water to the air, “Arbabian said.

“We expect this technology to be installed on helicopters or drones, which can operate at an altitude of tens of meters above water,” said Aidan Fitzpatrick, lead author of the study.

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