Alternative to X-Rays Uses Visible Light : Discovery News: "The laser created the light, which was sent through the modulator, and illuminated the image (in their tests, a rose). The green light bounced off the image and through a glass slide that was painted white, which scatters the light in all kinds of different directions.
Ordinarily that would be the end of it; the image captured by the digital camera would be blurred beyond all recognition. The French scientists got around this limitation by taking picture after picture of the blurred image, and then applying a program that accounts for how the light is scattered by the white glass. That way they could reassemble a grainy image of the flower."