Researchers modeled virtual periscope on astronomers’ technology used to counter blurring and distortion caused by layers of atmosphere when viewing stars
“Up periscope!” may become a submarine commander's outdated order, thanks to a team of Technion-Israel Institute of Technology researchers who have developed a new technology for viewing objects above the water's surface without a periscope poking its head above the waves.
The technology behind a submerged, “virtual periscope” will be introduced in a presentation at the IEEE International Conference on Computational Photography, held May 2-4, 2014 in Santa Clara, Calif. ( http://www.iccp14.org/ ])
Associate Professor Yoav Y. Schechner, of the Technion Department of Electrical Engineering, and colleagues, developed the virtual periscope called “Stella Maris” (Stellar Marine Refractive Imaging Sensor). The heart of the underwater imaging system is a camera, a pinhole array to admit light (a thin metal sheet with precise, laser-cut holes), a glass diffuser, and mirrors. Sunrays are projected through the pinholes to the diffuser, which is imaged by the camera, beside the distorted object of interest. The latter is then corrected for distortion.
“Raw images taken by a submerged camera are degraded by water-surface waves similarly to degradation of astronomical images by our atmosphere. We borrowed the concept from astronomers who use the Shack-Hartmann astronomical sensor on telescopes to counter blurring and distortion caused by layers of atmosphere,” explains Schechner. “Stella Maris is a novel approach to a virtual periscope as it passively measures water and waves by imaging the refracted sun.”
The unique technology gets around the inevitable distortion caused by the water-surface waves when using a submerged camera, according to Schechner, because of the sharp refractive differences between water and air, random waves at the interface present distortions that are worse than the distortion atmospheric turbulence creates for astronomers peering into space.
“When the water surface is wavy, sun-rays refract according to the waves and project onto the solar image plane,” explains Schechner. “With the pinhole array, we obtain an array of tiny solar images on the diffuser.” When all of the components work together, the Stella Maris system acts as both a wave sensor to estimate the water surface, and a viewing system to see the above surface image of interest through a computerized, “reconstructed” surface.
The Stella Maris virtual periscope is just the latest technology developed by the researchers, who have also found ways to exploit “underwater flicker,” i.e., random change of underwater lighting, caused by the water surface wave motion. Members in the Schechner Hybrid Imaging Lab (http://webee.technion.ac.il/~yoav/lab-and-group/) turned the tables on underwater flicker and used the natural rapid and random motion of the light beams to obtain three-dimensional mapping of the sea floor.
According to the developers, the virtual periscope may have potential uses in addition to submarines, where they could reduce the use of traditional periscopes that have been in use for more than a century. Submerged on the sea floor, Stella Maris could be useful for marine biology research where and when viewing and imaging both beneath and above the waves simultaneously is important. Stella Maris could, for example, monitor the habits of seabirds as they fly, then plunge into water and capture prey.
“There are many ways to advance the virtual periscope,” says Schechner, who adds that while the system requires sunlight, they are currently working on a way to gather enough light from moonlight or starlight to be able to use the system at night.
Also contributing to this research were current graduate student Marina Alterman and former graduate student Dr. Yohay Swirski (who is now working in industry). The research was conducted in Schechner's Hybrid Imaging Lab in the Technion Department of Electrical Engineering.
The Technion-Israel Institute of Technology is a major source of the innovation and brainpower that drives the Israeli economy, and a key to Israel's renown as the world's “Start-Up Nation.” Its three Nobel Prize winners exemplify academic excellence. Technion people, ideas and inventions make immeasurable contributions to the world including life-saving medicine, sustainable energy, computer science, water conservation and nanotechnology. The Joan and Irwin Jacobs Technion-Cornell Innovation Institute is a vital component of Cornell NYC Tech, and a model for graduate applied science education that is expected to transform New York City's economy.
American Technion Society (ATS) donors provide critical support for the Technion - more than $1.9 billion since its inception in 1940. Based in New York City, the ATS and its network of chapters across the U.S. provide funds for scholarships, fellowships, faculty recruitment and chairs, research, buildings, laboratories, classrooms and dormitories, and more.
Kevin Hattori | newswise
Spiral arms: not just in galaxies
30.09.2016 | Max-Planck-Institut für Radioastronomie
Discovery of an Extragalactic Hot Molecular Core
29.09.2016 | National Astronomical Observatory of Japan
Heavy construction machinery is the focus of Oak Ridge National Laboratory’s latest advance in additive manufacturing research. With industry partners and university students, ORNL researchers are designing and producing the world’s first 3D printed excavator, a prototype that will leverage large-scale AM technologies and explore the feasibility of printing with metal alloys.
Increasing the size and speed of metal-based 3D printing techniques, using low-cost alloys like steel and aluminum, could create new industrial applications...
Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.
Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...
Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.
Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...
The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.
“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...
With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.
Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...
30.09.2016 | Event News
29.09.2016 | Event News
28.09.2016 | Event News
30.09.2016 | Materials Sciences
30.09.2016 | Earth Sciences
30.09.2016 | Life Sciences