China team brings X-ray vision to life with a compact high-speed ghost video cam

Chinese scientists have developed a compact tabletop X-ray ghost imaging system capable of capturing real-time "see-through" video of rapidly moving objects, such as rotating aircraft engines or beating hearts. The innovative method requires less radiation and is simpler to set up than traditional X-ray techniques. According to a paper published in Communications Physics on August 15, the system can produce high-resolution images at a rate of up to 200 frames per second.

The researchers from the Chinese Academy of Sciences and Shanghai Jiao Tong University claim their method has significant potential for medical imaging and non-destructive inspection of moving mechanical components. Conventional tabletop X-ray imaging, while useful for static objects, suffers from operational limitations that restrict its applicability to dynamic objects.

Traditional X-ray imaging works by shooting radiation through an object, which different materials absorb to varying degrees, and capturing the resulting image with a detector. In contrast, X-ray ghost imaging is an indirect technique that uses an object lit with X-rays passing through a patterned filter. A single-pixel detector measures the total intensity of light that reaches it, and a computer uses this data to reconstruct the final image.

Existing X-ray ghost imaging methods are hampered by long acquisition times, making them unsuitable for real-world applications. To address this issue, the Chinese team's method employs a rapidly rotating filter or mask with tiny patterns, allowing for faster image acquisition. Their method successfully imaged a spinning copper disk with letters, although the image quality deteriorated as the disk spun faster.

While the ghost imaging system produced lower-quality images than traditional X-ray cameras, it was able to continuously record the full motion of the moving letters without frame gaps or distortion. The imaging speed of the ghost approach is primarily limited by the rotation speed of the spinning mask and the sampling frequency of the detection system.

The team believes that improving both factors could lead to even faster and better imaging. The new method is applicable to any wavelength and is particularly suitable for situations where array cameras are cumbersome, expensive, and difficult to maintain.