The News Herald (Willoughby, OH)
Your pupils could one day control office lights
Your pupils could one day control the lights in your office
An advanced webcam captures data that is used to calculate each person’s optimal lighting comfort level.
When researcher Joon Ho Choi taps on his keyboard, his computer looks deep into his eyes.
No, this is not a Skype call. And it’s definitely not some sci-fi, man-meets-machine rom-com scenario as depicted in the 2013 Hollywood movie “Her.”
Using a computer’s camera, Choi’s advanced webcam — his pupilo meter — captures eye pupil-size data that are then used to calculate each person’s optimal lighting comfort level in real time. The USC professor’s experimental model is the first in the nation to connect indoor climate controls with physiological data.
The applications are eagerly eyed by industry giants such as Siemens, maker of automated room controls, and Buro Happold, a global engineering firm, as a way to advance hightech home and office indoor climate systems. And environmental agencies are interested in the energy savings possible from integrating building system controls with living, breathing humans.
Reduction in greenhouse gases
If Choi’s system was used in all 5.6 million commercial buildings in the United States that have lighting, the energy load would be reduced by 8.2 billion kilowatt-hours. That’s around the amount of energy used by more than 760,000 residential customers in the United States in 2016, according to averages supplied by the U.S. Energy Information Administration.
That kind of energy savings would result in a reduction of nearly 80 million metric tons of carbon dioxide, the main greenhouse gas contributing to global climate change. In 2015, California emitted 364 million metric tons of CO2.
An assistant professor of the building science division of the USC School of Architecture, Choi said that offices easily can cut down on energy use by at least 50 percent — and help their workers feel more comfortable since most offices are over-lit.
“They work under toobright conditions and then they are exposed to glare,” Choi said. “That means it can cause eye fatigue or eye strain and you can damage your visual acuity and lower your productivity.”
Better lighting for both paper and computer workstations increases productivity, decreases sick-building syndrome symptoms and reduces visual stress that leads to eye injuries. The result is fewer employees becoming ill and missing work, Choi said.
Are everyone’s eyes different?
Choi says measuring eye pupil size while a person is working helps him generate a value for “optimal visual comfort.”
That value, or personal number, is calculated by a computer program that tracks and stores eye data while the person works. Then the workstation can be equipped with a dimmer switch to ratchet up or down the desk station lighting according to that number.
Choi is working on a prototype that uses a device resembling ski goggles, a micro-camera and a specially designed circuit board to detect pupil sizes and assess light levels.
He’s perfecting the system’s sensors that will automatically adjust lighting based on the user’s realtime pupil-size data.
“Sometimes they’ll use the interface at the beginning, say, the first and second days they enjoy using the controller, but a week later they don’t. That’s why we believe it should be automatic,” Choi said.
While stimuli such as stress are averaged out of the calculations, Choi had to accommodate eye color, ethnicity, age and myopia into the algorithms.
Are people with blue eyes and light skin tones more susceptible to the effects from bright indoor lights, just as they are with sunlight? “Right now we cannot tell. We are still connecting the data,” he said.
But research has shown that older people need different light levels than younger people. “Senior citizens need higher lighting levels than younger groups, so we cannot say the same lighting levels will work for everyone. That’s why we have to base it on the individual,” Choi said.
Data is not published or sold, Choi said. To ensure privacy, he’s working with a data security expert and USC professor Shri Narayanan, he said. He hopes to publish his study in the Journal of Building and Environment in June.
EPA funding granted
Choi received a $299,000 grant on Aug. 27, 2017, from the National Science Foundation for his research. Later, he was awarded $15,000 from the EPA with the possibility of a grant of up to $75,000 to test his lighting system in a realworld setting.
“The support from the National Science Foundation affirms the potential groundbreaking work of Professor Choi and his collaborators. We are excited for Professor Choi, our school, and for the impacts that his research will deliver in the coming years,” said Milton Curry, dean of the USC architecture school, in a statement.
Choi will present his work at the U.S. Environmental Protection Agency’s National Sustainable Design Expo, a kind of science fair for scientists, today and Sundayin Washington, D.C. He and four graduate students will demonstrate the system and discuss their findings.
The potential applications of the system could one day expand beyond office lighting — to heating, air conditioning, color schemes and more.
“Nobody has tried this,” Choi said.