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The University of Texas at San Antonio Online Magazine


Let there be light

For more than 30 years, UTSA associate psychology professor James Dykes has studied human visual information processing: how people read, detect visual stimuli and view color.

Over that period, most of his research focused on two areas: photopic vision, how people view the world in the daylight, and scotopic vision, how it appears to them at night.

But about 15 years ago, new research interests developed for many researchers around the country, including Dykes, in the area of mesopic vision. Mesopic vision takes place at dusk, in between the photopic and scotopic levels of light.

To conduct the research, Dykes, funded by a $143,000 Air Force Research Laboratory grant in fall 2007, set up a laboratory environment where black felt is placed over the walls and light-proof seals are applied around the doorways. Graduate students wear night vision goggles to record the responses of participants when they are shown colors on a computer monitor.

The computers are set at a lower level then what would be found at a low photopic range, as would be found in an office environment. Filters are added to progressively darken the monitors through the mesopic range and into the scotopic range. This allows the researchers to measure how acuity and color perception change as vision adapts from day through dusk to night.

According to Dykes, the Air Force is interested in the research because many of their flights take off at dusk and the cockpit displays are dimly lit to avoid detection by other aircraft.

“If a pilot can’t tell what color his warning light is, then it can be a problem,” Dykes says.

Dykes says the research is not only important to the Air Force, but the Department of Transportation is also interested because many accidents occur at dusk.

- Kris Rodriguez

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