Researchers at Oxford University have hacked an off-the-shelf digital camera to capture stills at 400 frames per second, which can then be sown together to produce high-speed video.
Physiologist Dr Peter Kohl studies the human heart. His team is currently using an animated computer model of the organ, which details its many angles and layers, right down to cellular level.
However, gathering the photographic evidence of, for example, heart cells in action, was proving difficult, as the cameras being used could not capture frames fast enough. Kohl says: “We may miss really vital information like very rapid changes in intensity of light from fluorescent molecules that tell us about what is happening inside a cell.”
To upgrade to higher speed cameras was not a viable, financial option and so instead, one of the researchers has managed to combine the technology from an average digital compact camera with a component from a home cinema projector.
Dr Gil Bub took the digital chip from within the projector and fixed this between the lens and image sensor in the camera. As New Scientist explains: The projector chip is “studded with tiny, moving mirrors, each of which controls the brightness of a pixel in the projected image”. These mirrors act within the camera as a kind of shutter, cutting every frame captured by the camera into 16 frames.
While Bub admits these frames are much lower resolution than the originals captured by the camera — 62,500 pixels instead of 1m pixels — they nevertheless boost the camera’s speed from 25 frames per second to 400 frames per second. The team could then either view the frames captured as one high-resolution still image or play the sub images one after the other to deliver a video.
And, most importantly, the set-up achieves these speeds at just a fraction of the cost of buying a suitable camera or video camera.
The team adds that the frame rate can be boosted further by simply adding a chip with even more mirrors in its arrays, and it has so far achieved capture at more than 6,000 frames per second.
The findings of the Oxford team have now attracted the attention of Cairn Research, a UK-based scientific instrument manufacturer, which has developed a product line for fast imaging of optical slices though cells. And a parallel project could see similar technology brought to consumer cameras.
Dr Mark Pitter from the University of Nottingham has created a custom-built solid state sensor that will perform the same role as the adapted mirror-array but for even less money.
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