"When light hits a glass of milk, a cloud, or our tissues, some of it is absorbed, but most of it is scattered," said Gigan. "You would think that this light is scattered beyond recovery, but it's not."
It's not imaging as we are used to seeing with X-rays or ultrasounds, said Changhuey Yang, a scientist at Cal Tech familiar with the new research. The image that comes through is grainy and can only work through think opaque surfaces. Nonetheless, Yang said it was "fascinating" that the French scientists could detect an image through a opaque medium.
When doing traditional imaging, like using X-rays to find hidden weapons at airports, "we assume that we know nothing about what is on the other side," said Yang. "In this scenario, this is not the case."
In other words, the French scientists knew what image is supposed to come through. If it were a totally random image coming through the glass it would be much more difficult to detect with their existing technique.
That should be possible one day, said Gigan, but right now its not. When it happens however, the technique could lead to a huge variety of applications.