Infrared and Ultraviolet Flash Cameras Make Appearance

Everyone has had that experience at one time or another in their life. You go on vacation with your family, or take the camera to your child's graduation or wedding. Maybe, you just want to take some pictures of your family at the local park. You get so excited, because you know you get some great shots. You plug the camera into your computer and realize the awful truth. Sure, you took some great shots. Sure, you had some photos that would rival Ansel Adams. However, your pictures are either too dark when you turned the flash off, or the glare made it impossible to tell what your picture even showed.

According to newscientist.com, that problem could be a thing of the past. Dilip Krishnan and Rob Fergus, heads of the photography department at New York University, have created a camera that uses infrared and ultraviolet light to do away with the troublesome flash while still lighting the .picture perfectly.

Basically, the infrared or Ultraviolet light is delivered in a less concentrated form than a regular flash, so the pulse of light appears up to two hundred times less bright than a normal flash.

While the "dark flash" delivers a crisp image, it distorts the color balance, giving the image a yellowish-green color something akin to a picture taken in night-vision. To correct this, Fergus and Krishnan use a second image taken with natural lighting, taken quickly after the first. Using special software and a fairly complex post process operation within the camera, the photos are combined to make a natural-looking image with great lighting.

However, as with any new technology, there are some bugs that remain. Because some objects absorb UV and infrared light instead of reflecting it, certain things don't appear in the final image. For example, in a test run of the camera, Fergus took a picture of himself, and found that his freckles and some minor skin blemishes were invisible in the computer-reconstructed image. Most would consider this an advantage rather than a fall back. However, Fergus and Krishnan are more concerned with photographic accuracy.

The original paper, in which Dilip Krishnan and Rob Fergus detail the processes that the camera uses can be found here.

The creators of this prototypical technology plan to present their work at the SIGGRAPH (Special interest group on GRAPHics and interactive techniques) Conference in New Orleans in August 2009.

Source: http://cs.nyu.edu/~fergus/papers/dark_flash.pdf