It's About Time!

Femto Photography can capture the motion of light.

Since the introduction of digital photography, researchers have focused on increasing spatial resolution. With more megapixels of data from the sensor, a camera can better simulate the human optical system. Today, when every smart phone has a high resolution sensor, researchers are moving beyond resolution and capturing images that explore other dimensions.  One of the new dimensions discussed at SIGGRAPH this month was time.

Ramesh Raskar and a team of scientists at MIT have developed Femto Photography, a method to capture images with an exposure of a trillionth of a second. This capture is fast enough to track the propagation of light through a scene.  When a series of these frames are assembled into a slow motion video, we can actually see the path of the light.

One of the interesting potential applications for Femto-Photography is medical imaging. As light travels into a semi-transparent surface, like human skin, the light scatters beneath the surface and some of it reflects back in the direction of the camera. Analysis of this sub-surface scattering could reveal the composition of the tissue below the surface.

The method can also be used to see around corners. Light which bounces off of a door into a room will travel different distances to each of the items in the room. By comparing the times when the photons bounce back to the camera, the positions of everything in the room can be computed.

Time is just one of many new dimensions that can be explored using computational imaging. What would you like to see?

Ramesh Raskar explains Femto Photograhy at TED 2012

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