Research duo develop a means for people to conceptualize polarized light

Dec 18, 2013 by Bob Yirka report

(Phys.org) —Two researchers from Queensland University in Australia have developed a way to describe polarizing objects in a way that can be visualized by the human eye. In their paper published in Proceedings of the Royal Society B: Biological Sciences, Martin How and Justin Marshall describe a technique they have developed for using attributes of polarization to describe what they call "polarization distance."

It's a well-known fact that animals other than humans can see polarized and that many use it as a means of navigation, terrain discrimination or even as a form of communication. Recent studies have even found that some organisms, such as shrimp, are able to communicate with one another using polarized light that is reflected off a part of their bodies, in this case, their tails. Many scientists believe that there likely exists a hidden world of communication going on in natural world, where only those who can see polarized light are able to join in. How and Marshall describe it as a secret language—one where prey are able to communicate silently, for example, unseen by a predator, without fear of being overheard.

Unfortunately, because it is invisible to the , researchers have had a hard time studying the impact of on animals and the ways they use it. To help in this area, How and Marshall have come up with a way to use several attributes of polarization to mimic what is known as "color distance," which in normal light is calculated by quantifying saturation, hue and intensity. In this case, they instead use attributes of polarized light—percentage, intensity and angle—to provide a means for estimating the discriminability of objects in .

Creating a characteristic of polarization based on actual attributes allows for calculating polarization distance, which in turn can be used to convert polarized reflections into false colors the human eye can see. That in turn, the researchers hope, will lead to the creation of devices that will allow scientists to study the hidden world of communications used by animals in a more natural way—by "listening in" on their secret signals and noting how those that can see them respond.

Explore further: Narrow channel that acts as polarization filter adds new dimension to optical data transmission

More information: Polarization distance: a framework for modelling object detection by polarization vision systems, Published 18 December 2013 DOI: 10.1098/rspb.2013.1632

Abstract
The discrimination of polarized light is widespread in the natural world. Its use for specific, large-field tasks, such as navigation and the detection of water bodies, has been well documented. Some species of cephalopod and crustacean have polarization receptors distributed across the whole visual field and are thought to use polarized light cues for object detection. Both object-based polarization vision systems and large field detectors rely, at least initially, on an orthogonal, two-channel receptor organization. This may increase to three-directional analysis at subsequent interneuronal levels. In object-based and some of the large-field tasks, the dominant e-vector detection axes are often aligned (through eye, head and body stabilization mechanisms) horizontally and vertically relative to the outside world. We develop Bernard and Wehner's 1977 model of polarization receptor dynamics to apply it to the detection and discrimination of polarized objects against differently polarized backgrounds. We propose a measure of 'polarization distance' (roughly analogous to 'colour distance') for estimating the discriminability of objects in polarized light, and conclude that horizontal/vertical arrays are optimally designed for detecting differences in the degree, and not the e-vector axis, of polarized light under natural conditions.

Related Stories

Capturing an octopus-eye view of the Great Barrier Reef

Jan 27, 2012

A specialized camera that allows scientists to see as reef-dwelling animals do has been built by a team of researchers at the University of Bristol. The team will travel to Lizard Island off the coast of Queensland this year ...

Measuring magnetic fields

Apr 09, 2012

(Phys.org) -- Polarized light is a familiar phenomenon, as people who prefer polarized sunglasses can testify. The electric field in a beam of light can vibrate either left-right or up-down, and the scattering ...

Recommended for you

Male monkey filmed caring for dying mate (w/ Video)

Apr 18, 2014

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Orchid named after UC Riverside researcher

Apr 17, 2014

One day about eight years ago, Katia Silvera, a postdoctoral scholar at the University of California, Riverside, and her father were on a field trip in a mountainous area in central Panama when they stumbled ...

In sex-reversed cave insects, females have the penises

Apr 17, 2014

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but re ...

Fear of the cuckoo mafia

Apr 17, 2014

If a restaurant owner fails to pay the protection money demanded of him, he can expect his premises to be trashed. Warnings like these are seldom required, however, as fear of the consequences is enough to ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Plants with dormant seeds give rise to more species

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.