23-April-2007, 08:50 PM
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Banned
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Join Date: Mar 2007
Posts: 68
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Everything starts with recognition
Published: 6 hours ago, 10:35 EST, April 23, 2007
http://www.physorg.com/news96543355.html
Study shows how brain interprets surfaces
http://www.physorg.com/news96299370.html
Quote:
Studying how the brain analyzes surface appearance is not only important to understanding the workings of the human brain, but could also help scientists develop better visual systems for robots.
"We know a lot about the perception of objects, but much less about the perception of the materials that the objects are made of," said Edward Adelson, an author of the paper and professor of visual science in the Department of Brain and Cognitive Sciences at MIT. "Our studies show that statistical skewness, which quantifies an asymmetry between light and dark patterns, has a strong influence on the way a material is perceived."
Analyzing visual attributes such as color, texture, and gloss, is critical in everyday tasks such as deciding whether a patch of pavement is icy, whether a pancake is cooked, or whether skin is healthy, according to the researchers.
In their experiments, the research team asked subjects to rate the lightness and glossiness of natural materials such as stucco or fabric. The surfaces have a mix of dark shadows and bright highlights, giving rise to distinctive visual patterns.
"Natural surfaces are complicated," said Adelson. "They have bumps and dips, and the light reflects in complex ways, producing characteristic statistical patterns." These patterns serve as signatures both for the shape and the material composing the surface.
The researchers quantified the images in terms of "luminance histograms," which plot the distribution of pixel values. They also estimated the histograms of responses of neurons that respond to light and dark spots in an image. In both cases, they found that the "skewness" of the histogram, which measures its asymmetry, was correlated with the subject's perceptions of surface qualities. Positive skewness led to darker and glossier surface appearance.
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To understand the big picture, give it time -- and sleep
http://www.physorg.com/news96287306.html
Mathematician suggests extra dimensions are time-like
http://www.physorg.com/news96027669.html
Last edited by South East; 23-April-2007 at 09:00 PM..
Reason: <b< statistical skewness >b>
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