The ghost imaging approach boasts several advantages, such as with the technique enabling apparatus to form an image by illuminating an object with lower light levels when compared with conventional imaging approaches.
Ghost imaging (or “coincidence imaging”) is a method that generates an image of an object by combining information from two light detectors. The detectors are a conventional, multi-pixel detector which does not view the object, and a single-pixel detector that does view the object.
To date, ghost imaging has been limited to non-moving objects since it takes considerable time to project the necessary sequence of light patterns onto an object, so that a high-quality image can be reconstructed an image. When applied to moving objects, these have tended to be rendered blurry.
This problem has been overcome by scientists at the National University of Defense Technology in China. Here researchers have succeeded in combining information collected from the blurry images of moving objects together with data relating to an object’s location. The combination of data, when processed using digital technology, leads to high quality images of moving objects being produced through ghost imaging.
The new technique deploys light patterns to capture the position and trajectory of an object. To interpret the data, the scientists developed an algorithm which can cross correlate positional information with blurred images.
By processing the data through a computer program, a clear image is gradually formed. One advantage with this is the low-level of computing power required, and without the need for any additional technology outside of the standard ghost imaging of stationary objects.
Commenting on the research, Wei-Tao Liu, from the Chinese university, states: “Our work shows that blurred images contain useful information. With further improvements, this approach could make ghost imaging useful for applications such as biomedical imaging of human beings. If used with x-rays, for example, it could help reduce the radiation dose needed for imaging.”
The research has been published in the journal Optics Letters, where the research paper is headed “Gradual ghost imaging of moving objects by tracking based on cross correlation.”
