New York University researchers have developed a camera that uses ultraviolet (UV) and infrared (IR) light to take photos in the dark without the use of a traditional flash. To create the "dark flash" camera, Dilip Krishnan and Rob Fergus modified a flashbulb to emit light over a wide range of frequencies and filter out visible light. The researchers also removed the filters that usually prevent a camera's silicon image sensor from detecting IR and UV rays.
The dark flash is capable of creating a crisp image without disturbing the picture's subjects, but the image does have an odd color balance that looks as though the camera was using a night-vision scope. To create more normal hues, Krishnan and Fergus used color information from a brief, flash-free photograph of the same scene taken shortly after the dark flash photograph. The second image is dim and blurry, but software is used to combine the sharp detail from the first image with the natural colors from the second to create a clean, natural-looking final image.
A few problems still remain in the system, as some materials or objects absorb both UV and IR light and do not appear in the dark flash image or the final image. The researchers say that this type of camera could be used to remove unwanted reflections from images or to make instant three-dimensional models.
View an image gallery explaining the dark flash system.
From New Scientist
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