The scientists took advantage of the capability of a pixel photodiode to operate both in photoconductive and photovoltaic modes. It works in photoconductive mode while recording an image and in photovoltaic mode while charging the image sensor. Such a pixel was designed by Mr. Nayar.
The image sensor contains millions of these pixels which first record and reads out the image and then harvest energy to charge the sensor’s power supply. To store the energy, the camera uses a supercapacitor.
Though the resolution isn’t great, with its recording one image per second in a well-lit indoor space, theoretically it can record video FOREVER.
The team, led by Mr. Nayar, includes Daniel Sims, a research engineer and Mikhail Fridberg, a consultant from ADSP Consulting. They used off-the-shelf components to fabricate an image sensor with 30-by-40 pixels for the prototype camera.
The photodiodes operate in photoconductive mode only when the camera is capturing an image. The rest of the time they operate in photovoltaic mode so that the generated power could be used to charge other devices like phone or watch.
“We are in the middle of a digital imaging revolution.” says Mr. Nayar who heads the computer vision laboratory at the Columbia Engineering. “Digital imaging is expected to enable many emerging fields including wearable devices, sensor networks, smart environments, personalized medicine, and the internet of things. A camera that can function as an untethered device forever—without any external power supply—would be incredibly useful.”
According to NDTV, the team is going to present its work at the international conference on computational photography at the Rice University in Houston from April 24 to 26.
If scientists can refine this technology, we could have self-powered video cameras with multi-megapixel resolution in near future.
To know more of its technical details, take a look at the project published by the University.