Researchers have created a new wireless camera that can generate power by itself to be able to take pictures underwater without the need for a battery, which will allow researchers to explore and photograph the depths of the oceans that were not previously accessible and photographed.
The camera will allow scientists to search remote parts of the ocean to find new species, and it can also be used to track ocean pollution, monitor fish health and growth, and build more accurate climate models.
95% of the world's oceans are still mysterious to humans and have not yet been explored, and this percentage is greater than the unexplored area of the far side of the moon or the surface of Mars.
One of the biggest obstacles to deep ocean exploration is the high cost of operating an underwater camera for a long time, due to the need to connect it to a research vessel or send a ship to recharge its batteries, which constitutes a major challenge preventing the expansion of undersea exploration to a large scale.
Wireless camera without battery
In new research published in Nature Communications, MIT researchers have taken a big step toward overcoming this problem by developing a wireless, battery-free underwater camera that has the power to save up to 100 percent. A thousand times more than other undersea cameras.
According to the press release published by Eurek Alert, the device captures color images even in dark underwater environments, and transmits image data wirelessly through the water.
The camera derives the energy needed to work from sound, as it converts mechanical energy from sound waves traveling through the water into electrical energy that powers its imaging and communications equipment, and after capturing and encoding image data, the camera also uses sound waves to transmit data to a receiver that reconstructs the image.
Building accurate climate models
The statement also states that because it does not require a power source, the camera can run for weeks on end before it can be retrieved, allowing scientists to search remote parts of the ocean to find new species of organisms, and it can also be used to take pictures of ocean pollution or monitor ocean pollution. Fish health and growth in aquaculture farms.
“One of the most exciting applications of this camera to me personally is in the context of video surveillance,” says Fadel Adib, associate professor in the Department of Electrical Engineering and Computer Science and director of the Signal Kinetics group at the MIT Media Lab, and senior author of the paper. Climate. We build climate models, but we're missing data from more than 95% of the ocean, and this technology can help us build more accurate climate models and give a better understanding of how climate change is affecting the underwater world."
Adeeb is joined on the paper by co-authors and research assistants in the Signal Kinetics Group: Syed Saad Afzal, Walid Akbar, and Osfi Rodriguez, as well as research scientist Ansu Ha, and former researchers in the group: Mario Dumet and Reza Ghaffarivardavag.
piezoelectricity
The camera works by generating the necessary energy for it using transducers made of piezoelectric materials placed around the outside of it. Piezoelectric materials produce an electrical signal when a mechanical force is applied to them. When a sound wave traveling through water hits the transducers, it vibrates and converts that mechanical energy into energy. electric.
The statement also states that these sound waves can come from any source, such as a passing ship or marine life, and then the camera stores the harvested energy until it accumulates enough to power the electronics that take the images and deliver the data.
To keep power consumption as low as possible, the researchers used very low-power off-the-shelf imaging sensors.
The problem is that these sensors only capture grayscale images, and because most underwater environments lack a light source they also needed to develop a low-power flash.
“We were trying to reduce the hardware as much as possible, and that creates new limitations on how we build the system, send information and do the image reconstruction. It took a fair amount of creativity to figure out how to do that,” says Dr. Adeeb.
Merge photos to rebuild the scene
The researchers solved both problems simultaneously using red, green and blue LEDs. When the camera takes a picture, it lights a red LED and then uses the sensors to take the picture, then repeats the same process with the green and blue LEDs.
Dr. Akbar explains that although the image appears to be black and white, the red, green and blue colored light is reflected in the white part of each image, and when the image data is combined in post-processing the color image can be reconstructed.
"When we were kids in art class, we were taught that we can make all colors using 3 primary colors. We follow the same rules of color images we see on our computers, we only need red, green and blue - these three channels - to create color images."
Sending data by voice
Once the image data is captured, it is encoded in bits (1 and 0) and sent to a receiver one bit at a time using a process called underwater backscattering. The receiver transmits sound waves through the water to a camera, which acts as a mirror to reflect those waves. Either the camera reflects a wave back to the receiver or changes its mirror to an absorber so that the wave is not reflected back.
A microphone next to the transmitter senses the signal's reflection from the camera. When a signal is received, it's bit -1, and if there's no signal, it's bit 0. The system uses this binary information to reconstruct and process the image.
"This whole process, because it only requires one key to switch the device from a non-reflective state to a reflective state, it consumes 5 orders of magnitude less than normal underwater communication systems," Afzal says.
The statement states that the researchers tested the camera in different underwater environments, where they took color pictures of plastic bottles floating in a New Hampshire pond, and were able to take high-quality pictures of an African sea star so that the small tubercles along its arms were clearly visible, and the device was also effective in photographing Repeat plant underwater in a dark environment for a week to monitor its growth.
Important improvements
After demonstrating the success of the prototype in practice, the researchers plan to improve the device so that it is ready to operate in real-world conditions. They want to increase the camera's memory so you can take real-time photos, stream photos, or even shoot underwater video.
These researchers want to expand the camera's range. They have successfully transmitted data up to 40 meters from the receiver, but expanding this range will enable them to use the camera in more underwater environments.
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