1. An X-ray imaging apparatus comprising: a first X-ray generator which is configured to emit first X-rays toward a target object at a first emission angle; at least a second X-ray generator which is configured to emit second X-rays toward the target object at a second emission angle which is different from the first emission angle; a detector which is configured to detect the first X-rays and the second X-rays which have propagated through the target object; an image processor which is configured to acquire a first X-ray image from the detected first X-rays and to acquire at least a second X-ray image from the detected second X-rays, and to generate a stereoscopic image by using the acquired first X-ray image and the acquired at least second X-ray image; and a display which is configured to display the generated stereoscopic image.