First 3D Ghost Images From a Single Pixel
Chinese physicists use ghost imaging technique to make 3D images with a single pixel
Ghost imaging is the extraordinary technique of bouncing a laser beam off an object and making high quality images from the reflected light using a single pixel. This single pixel records many data points which must be stitched together to create the image.
But there is no scanning involved (which would be equivalent to taking an ordinary picture very slowly).
Instead, the data from the single pixel is compared against the intensity of the original laser beam, which must be randomised by passing it through frosted glass. Then any correlations between the original and reflected beam reveal information about the object in the image.
It is these correlations that physicists use to assemble the [icture, known as a ghost image.
That may sound rather fiddly and time consuming but it is actually hugely efficient. The amount of data required to create an image in this way is tiny compared to the amount that ordinary imaging requires. It is possible to record the equivalent of a 5 megapixel image using just 50,000 pixels.
Physicists have demonstrated this technique in various different ways since 1995 but it is only in the last few years that they’ve begun to understand it properly and started to exploit it.