1. A 3D image generating method comprising: estimating depths of a 2D image to generate a 2D depth map having estimated depths; correcting the estimated depths of the 2D depth map to generate a corrected 2D depth map, by merging blocks neighboring to a marked figure line on the 2D depth map; creating a 3D model by connecting lines between pixels on the corrected 2D depth map having a depth difference smaller than a lower bound depth difference; determining at least one location; virtually positioning at least one virtual camera at the at least one location; and virtually recording the 3D model using the at least one virtual camera virtually positioned at the at least one location to generate a 3D image.