1. A system of revising depth of a three-dimensional (3D) image pair, comprising: a depth generator configured to generate at least one initial depth map associated with one image of the 3D image pair based on stereo matching technique, wherein the one image comprises a plurality of pixels, and the initial depth map carries an initial depth value of each pixel; and a depth revisor, comprising: an inconsistence detection unit configured to detect the inconsistence among the pixels based on two-directional occlusion detection technique and estimate a reliable map according to the detected inconsistence, wherein the reliable map is composed of a group of reliable points and a group of unreliable points, the reliable points comprises the pixels, a cost value of which is lower than a pre-defined threshold, and the unreliable points comprises the pixels, a cost value of which is higher than the pre-defined threshold; and an interpolation unit configured to interpolate the initial depth value according to the reliable map and a plurality of proximate pixels of the image, so as to generate a revised depth map by revising the initial depth value.