1. A method of calibrating a three-dimensional (3D) image in a tiled display that includes a display panel and a plurality of lens arrays, the method of comprising: capturing a plurality of structured light images displayed on the display panel; calibrating a geometric model of the tiled display based on the plurality of structured light images; generating a ray model based on the calibrated geometric model of the tiled display; and rendering an image based on the ray model, wherein the calibrating comprises: extracting principal observation ray (POR) pixels corresponding to light rays passing through an optical center of a capturing device from the plurality of structured light images; and calibrating the geometric model of the tiled display based on the extracted POR pixels.