1. A depth determination method, comprising steps of: acquiring a color image and a depth image from a camera; performing image identification based on the color image, and determining a first image region of the color image where a feature object is recorded; determining a second image region of the depth image corresponding to the first image region in accordance with a correspondence between pixels of the color image and the depth image; and determining a feature depth of the feature object based on depth information corresponding to the pixels at the second image region.