A self-powered video camera system is under development at Columbia University. Columbia University computer science professor, Shree Nayar, fashioned the self-powered camera with his colleague, research engineer Daniel Sims, plus Mikhail Fridberg, who founded ADSP Consulting in Sharon, Mass. The revolutionary research project is funded by the U.S. Office of Naval Research, and could eventually result in battery-free cameras that never have to shut down.
This spring, Nayar presented his team’s research findings at the IEEE International Conference on Computational Photography at Rice University in Houston. Nayar pre-released a video showing the results of the team’s work. The images presented appear underwhelming at first glance, looking more similar to the output of a C19th moving daguerreotype to a contemporary camera using up-to-the minute technology. In low light, a man alters his facial expression as he moves his head up and down, then side to side. The current version of the camera captures black-and-white 30-by-40 pixel images every second in a scene that is approximately 300 lux in brightness.
The image may look crude; however the remarkable part is the technology behind it. The few self-powered cameras available on the market currently use solar cell batteries. By comparison, Nayar’s prototype camera instead uses a supercapacitor, which is charged continuously by energy derived from the image sensor’s pixels. This new light-powered technology could eventually result in battery-free cameras.
The camera system uses a sensor array, which collects and measures light in the same way that a traditional camera does; the novel part is that it combines this function with a photovoltaic cell’s ability to convert some of that light into energy. This results in a basic, yet self-sufficient digital camera. While image capture takes place, the pixels in the sensor that have recorded and produced the image then harvest energy and charge the sensor’s power supply.
The camera could function in extended periods of darkness through storing and using excess power harvested during the daytime to produce images at night. Shree Nayar described the rationale behind the project in relation to the growing need for cameras to be part of wearable devices and an increasingly crucial part of networks and the Internet of Things: “you want a device that is really small, high quality and can capture images untethered – and can do it forever”.