The Null Device

Heterodyne Light Field Camera

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.
The article has a slideshow, including some sample images. For some reason, they seem a bit dull, a bit like the images taken with digital cameras from 10 years ago; I wonder whether this is a result of the image reconstruction algorithm.

There are 2 comments on "Heterodyne Light Field Camera":

Posted by: toby Mon Apr 23 00:49:31 2007

It still relies on extracting a relatively low resolution image from an extrmely high resolution CCD, so I don't see it being particularly useful. Even if you want to play with multiply focussed images (have you seen Haeberli's work on that?: http://groups.csail.mit.edu/graphics/pubs/npar2004_imagefusion.pdf) it's easier to just take several images with your camera on a tripod.

This bit is particularly interesting:

Q. How do you print these masks?

For Coded Focus Camera, the broadband mask is a binary 7 by 7 pattern (49 holes, approximately half opaque and half transparent). The size of each hole is >1mm^2 (to avoid diffraction). This can be printed easily as a standard emulsion based transparency. Printing cost is cheap, one can get 20 of these masks printed on a single A4 size transparency for $50. For amateur photography, one can print the mask on a standard overhead transparency on home printer.

Posted by: toby Mon Apr 23 00:50:43 2007

That URL is completely wrong, although it's on a smilar topic.

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