The Null Device

Scientists at Mitsubishi have developed a camera which allows photos to be refocussed after being taken. Unlike previous experiments in this field, this system retains the full resolution of the camera's image sensor in the resulting image. It uses a special lens with a semi-transparent patterned mask (resembling a crossword puzzle) in the middle:

Using the combination of the mask and the post-processing software, MERL researchers were able to reconstruct a 4D light field from the standard 2D camera, explained MERL Visiting Scientist Amit Agrawal. Instead of bending light rays, the patterned mask attenuates the rays inside the camera. The post-processing software reconstructs the light field using an inverse computation of the Fourier transform equation, allowing the user to refocus the image.

(via gizmodo) ¶ light field photography photography research science tech 2

Scientists have developed a camera that takes pictures that can be refocussed afterward, by keeping track not only of the intensity of incoming light but of its angle as well.

Now, Pat Hanrahan and his team at Stanford University have figured out how to adjust the light rays after they have reached the camera. They inserted a sheet of 90,000 lenses, each just 125 micrometres across, between the camera's main lens and the image sensor. The angle of the light rays that strike each microlens is recorded, as well as the amount of light arriving along each ray. Software can then be used to adjust these values for each microlens to reconstruct what the image would have looked like if it had been properly focused. That also means any part of the image can be refocused - not just the main subject.

Applications of this technology include surveillance (where being able to change focus after the fact would often be useful) and motion photography; I imagine we may see this in films, music videos and ads soon enough as well.

¶ camera light field photography photography 4