1. An x-ray imaging method, comprising: causing an x-ray source and an x-ray detector to move about an object to a plurality of different positions; generating a two-dimensional x-ray image of the object at each of the plurality of different positions; generating a plurality of optical images of the object using an optical camera during the movement of the x-ray source and the x-ray detector about the object; determining a movement trajectory of the object relative to the x-ray detector based on the plurality of optical images; and calculating a three-dimensional x-ray image of the object based on the plurality of two-dimensional x-ray images and the movement trajectory of the object relative to the x-ray detector.