A collaborative research team has made improvements to a new camera technology capable of imaging at speeds 100 times faster than today’s commercial cameras, while also capturing more image frames. The new technology will allow for new possibilities when it comes to studying extremely fast processes, such as neurons firing, chemical reactions, fuel burning or exploding chemicals.
The new single-shot compressed ultra-fast photography (CUP) camera can image at speeds of 100 billion frames per second in a single camera exposure—fast enough to capture traveling light pulses. The camera is the world’s fastest camera that is receive-only, which means it can use available light to snap images, without requiring any additional illumination from a laser or other light source.
Though that camera had extreme capabilities, the team, led by Lihong V. Wang, Gene K. Beare Distinguished Professor of Biomedical Engineering at Washington University, St. Louis, thought they could improve upon it even more. The researchers’ new method upgrades the resolution and quality of images captured with CUP. They demonstrate the CUP upgrades by capturing a movie of a picosecond laser pulse traveling through the air, as well as by pointing laser light onto a printout of a toy car to create a movie of the light reaching different portions of the car at different times.
Wang and the team are interested in understanding how the brain’s neural networks operate. Their new camera, along with a microscope, could allow them to watch neurons fire by capturing extremely fast chemical processes called action potentials that travel through an axon at speeds that can reach more than 100 meters per second.
“We want to use our new camera to study a living animal’s neural network in action,” said Wang. “This would reveal how the neural network functions, not just how the neurons are connected. If you were to think of the neural network as streets in a city, right now we can see the layout of the streets, but we want to see the traffic to understand how the whole system functions.”
The improved image resolution and quality mean that the camera could better capture entire action events.
“Biological reactions can occur very fast, faster than standard cameras can image,” said Wang. “When people study events like that now, they use a pump-probe method, which requires them to repeat the event many times. Our camera can be used for real-time imaging of a single event, capturing it all in one shot at extremely high speeds.”
In addition to medical applications, the camera’s ability to image with just the light available to it, makes it a potential tool to be used in conjunction with telescopes to record activities of a supernova that occur light years away. According to Wang, the CUP camera could, for example, add high-speed imaging to space telescopes like the Hubble.
Another application area could include imaging explosives.
“For explosions, the chemical reactions may not be repeatable, so it is important to capture everything with a single event in real time,” said Wang. “The camera could also help scientists studying combustion so that they could improve the fuel efficiency of cars, for example.”
How It Works
The original version of the CUP camera adds a second dimension to the one-dimensional view of a streak camera—an extremely fast type of camera that measures the intensity variation of a pulse of light over time. Computer algorithms are employed to convert this data into an image because the approach cannot directly create an image.
The team’s upgrade includes an additional external charge-coupled device (CCD) that provides more information for the image to be constructed out of. This leads to higher-quality images. The researchers also developed a new algorithm to combine the data from the external CCD with the data from the streak camera. These improvements generated images with finer spatial resolution, higher feature contrast and cleaner background.