Featured Research

from universities, journals, and other organizations

Submarine: 'Virtual periscope' sees above-surface/airborne objects from underwater view

Date:
April 29, 2014
Source:
American Technion Society
Summary:
Researchers have developed an underwater imaging system that allows submariners to view objects above the water's surface - without a periscope. The unique technology gets around the inevitable distortion caused by the water-surface waves when using a submerged camera 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.

Distorted (left) and corrected views from underwater. 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.
Credit: Image courtesy of American Technion Society

"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 may become a submarine commander's outdated order, thanks to a team of Technion-Israel Institute of Technology researchers who have developed a new technology for viewing objects above the water's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.

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 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.


Story Source:

The above story is based on materials provided by American Technion Society. The original article was written by Kevin Hattori. Note: Materials may be edited for content and length.


Cite This Page:

American Technion Society. "Submarine: 'Virtual periscope' sees above-surface/airborne objects from underwater view." ScienceDaily. ScienceDaily, 29 April 2014. <www.sciencedaily.com/releases/2014/04/140429092545.htm>.
American Technion Society. (2014, April 29). Submarine: 'Virtual periscope' sees above-surface/airborne objects from underwater view. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2014/04/140429092545.htm
American Technion Society. "Submarine: 'Virtual periscope' sees above-surface/airborne objects from underwater view." ScienceDaily. www.sciencedaily.com/releases/2014/04/140429092545.htm (accessed October 21, 2014).

Share This



More Matter & Energy News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gulfstream G500, G600 Unveiling

Gulfstream G500, G600 Unveiling

Flying (Oct. 20, 2014) Watch Gulfstream's public launch of the G500 and G600 at their headquarters in Savannah, Ga., along with a surprise unveiling of the G500, which taxied up under its own power. Video provided by Flying
Powered by NewsLook.com
Japanese Scientists Unveil Floating 3D Projection

Japanese Scientists Unveil Floating 3D Projection

Reuters - Innovations Video Online (Oct. 20, 2014) Scientists in Tokyo have demonstrated what they say is the world's first 3D projection that floats in mid air. A laser that fires a pulse up to a thousand times a second superheats molecules in the air, creating a spark which can be guided to certain points in the air to shape what the human eye perceives as an image. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
What We Know About Microsoft's Rumored Smartwatch

What We Know About Microsoft's Rumored Smartwatch

Newsy (Oct. 20, 2014) Microsoft will reportedly release a smartwatch that works across different mobile platforms, has a two-day battery life and tracks heart rate. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins