  Hard x-ray imaging is indispensable across diverse fields owing to its high
penetrability. However, the resolution of traditional x-ray imaging modalities,
such as computed tomography (CT) systems, is constrained by factors including
beam properties, the absence of optical components, and detection resolution.
As a result, typical resolution in commercial imaging systems is limited to a
few hundred microns. This study advances high-photon-energy imaging by
extending the concept of computational ghost imaging to multipixel ghost
imaging with x-rays. We demonstrate a remarkable enhancement in resolution from
500 microns to approximately 20 microns for an image spanning 0.9 by 1 cm^2,
comprised of 400,000 pixels and involving only 1000 realizations. Furthermore,
we present a high-resolution CT reconstruction using our method, revealing
enhanced visibility and resolution. Our achievement is facilitated by an
innovative x-ray lithography technique and the computed tiling of images
captured by each detector pixel. Importantly, this method can be scaled up for
larger images without sacrificing the short measurement time, thereby opening
intriguing possibilities for noninvasive high-resolution imaging of small
features that are invisible with the present modalities.
