Dilip Krishnan and Rob Fergus at New York University have developed a dark or invisible flash which uses infrared and UV light to take photos in dark places without the nasty glare of a standard flash. Their dark flash camera is made by modifying a flashbulb so that it emits light over a wider range of frequencies and filters out the visible light, and removes filters that prevent the silicon image sensor from detecting IR and UV rays. This flash results in a crisp image which does not have correct color balance, and looks like night vision photography. To correct the colors of the image, the camera also takes a quick color image sans flash right after the dark flash image. The image produced in this second image is predictably grainy and unclear, but the colors are correct. Software is then used
