Anyone who’s taken a picture of birthday candles being blown out or a selfie during a romantic candlelit dinner knows how disappointing it is when the photo comes out dark and grainy.
But University of Utah Electrical and Computer Engineering professor Rajesh Menon has developed a new camera color filter that lets in three times more light than conventional filters, resulting in much cleaner, more accurate pictures taken in lowlight. The new filter can be used for any kind of digital camera, but Menon is developing it specifically for smartphone cameras. Menon and doctoral student Peng Wang describe the invention today in the journal, Optica.
“Overall, camera phones are very good, but they are not very good in lowlight,” says Menon. “If you go out on a hike in the evening and take a picture of the sky you will see that it’s very grainy. Lowlight photography is not quite there and we are trying to fix that. This is the last frontier of mobile photography.”
Traditional digital cameras, whether they are point-and-shoot cameras or the now-ubiquitous smartphone cameras, use an electronic sensor that collects the light to make the picture. Over that sensor is a filter designed to allow in the three primary colors: red, blue and green. But by doing so, natural light hits the filter, and the filter absorbs two thirds of the color spectrum in order to let through each of the three primary colors.
“If you think about it, this is a very inefficient way to get color because you’re absorbing two thirds of the light coming in,” Menon says. “But this is how it’s been done since the 1970s. So for the last 40 years, not much has changed in this technology.”
Menon’s solution is to use a color filter that lets all light pass through to the camera sensor. He does this with a combination of software and hardware.
Read the full press release in the U News Center.