Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New angle on vision

08.11.2001


We judge distance from the ground up.
© Photodisc


Our brains use angular measurements to decide how far away objects are.

Even if trigonometry wasn’t your strong suit in school, your brain uses it constantly. You judge distance by measuring the angle between the ground and your line of sight to an object, a new study shows. The finding could improve the design of robots and artificial vision systems1.

Volunteers who looked through prisms that increased this angle thought objects were closer than they really were, missing them when throwing beanbags or trying to walk to them blindfolded.



Some prism-wearing participants even leaned forward, imagining that the ground was tilted away from them. "They tried to adjust their body perpendicular to the perceived ground surface," says Teng Leng Ooi of the Southern College of Optometry in Memphis, Tennessee, a member of the research team.

After just 20 minutes, volunteers adjusted to the distortion and judged distances correctly. This suggests that the brain possesses a ’plastic’ mechanism to tune its vision system to a constantly changing environment, the researchers say. When volunteers took the prisms off, they temporarily went to the opposite extreme, overestimating distances.

The experiments take a more "ecological" approach to vision processing than a lot of previous research, says Hal Sedgwick, who studies visual perception at the SUNY College of Optometry in New York City. "Rather than thinking of perception as occurring through an empty, abstract space, this looks at it from the point of view of an organism living in an environment, locating objects relative to the ground."


The long view

The idea that humans use the angle with the ground to measure distance is an old one. Ancient Chinese artists drew distant objects higher in the field of view, unlike European artists who generally relied on perspective, in which lines meet at infinity. The eleventh-century Arabic scholar Alhazen, whom some credit with having invented the scientific method, also hypothesized that humans use angles with the ground to judge distances.

Alhazen’s idea faded from attention over the years, and was resurrected only in the middle of the twentieth century, when psychologist James Gibson independently reached the same conclusion while helping to train pilots during World War II. Since then, however, the theory has lacked direct evidence.

For this reason, "this new study is quite important work," says Sedgwick. Ooi and colleagues have, he believes, produced "convincing evidence supporting the ground theory".

Understanding how humans process vision could help engineers to design more realistic virtual-reality systems and build robots that can navigate their environment better, Ooi suggests. It could even help people suffering from brain damage that interferes with their distance estimation, she says. "Research to elucidate space vision should help us predict the problems encountered by brain-injured patients, and to fix their problems through rehabilitation or compensatory robotic devices."

References

  1. Ooi, T. L. et al. Distance determined by the angular declination below the horizon. Nature, 414, 197 - 200, (2001).


ERICA KLARREICH | © Nature News Service
Further information:
http://www.nature.com/nsu/011108/011108-11.html

More articles from Interdisciplinary Research:

nachricht Bergamotene - alluring and lethal for Manduca sexta
21.04.2017 | Max-Planck-Institut für chemische Ökologie

nachricht How to color a lizard: From biology to mathematics
13.04.2017 | Université de Genève

All articles from Interdisciplinary Research >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Physicists Design Ultrafocused Pulses

Physicists working with researcher Oriol Romero-Isart devised a new simple scheme to theoretically generate arbitrarily short and focused electromagnetic fields. This new tool could be used for precise sensing and in microscopy.

Microwaves, heat radiation, light and X-radiation are examples for electromagnetic waves. Many applications require to focus the electromagnetic fields to...

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

 
Latest News

Programming cells with computer-like logic

27.07.2017 | Life Sciences

Identified the component that allows a lethal bacteria to spread resistance to antibiotics

27.07.2017 | Life Sciences

Malaria Already Endemic in the Mediterranean by the Roman Period

27.07.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>