Effect of measurement reduction on synthetic aperture x-ray ghost imaging

The unique advantage of x-ray ghost imaging (XGI) is its potential in low dose radiology. One of the practical ways to reduce the radiation exposure is to reduce the measurements while remaining sufficient image quality. Synthetic aperture x-ray ghost imaging (SAXGI) is invented to achieve megapixel XGI with limited measurements, which is expected to implement XGI simultaneously with large field of view and low radiation exposure. In this paper, we experimentally investigate the effect of measurements reduction on the spatial resolution and image quality of SAXGI with standard sample and biomedical specimen. The results with a resolution chart demonstrated that at 360 measurements, SAXGI successfully retrieved the sample image of 1960 × 1960 pixels with spatial resolution of 4 μm. With measurement reduction, the spatial resolution deteriorates but the sparser structures are still discernable. Even with measurements reduced to 10, a spatial resolution of 10 μm can still be achieved by SAXGI. A biomedical sample of a fish specimen is employed to evaluate the method and the fish image of 2000 × 1000 pixels with an SSIM of 0.962 is reconstructed by SAXGI with 770 measurements, corresponding to an accumulative exposure reduction of more than 2 times. With the measurements reduced to 10 which corresponds to 1/160 of the accumulative radiation exposure for conventional radiology, bulky structure like the fish skeleton can still be definitely discerned and the SSIM for the reconstructed image still retained 0.9179. Results of this paper demonstrate that measurements reduction is practicable for the radiation exposure reduction of the sample, which implicates that SAXGI with limited measurements is an efficient solution for low dose radiology.