Human of eyes apart 6~7cm, has must of distance, so in observation a three dimensional objects Shi, due to two eye level separate in two a different of location Shang, by observation to of objects image is different of, they Zhijian exists with a like poor, due to this like poor of exists, through human of brain, we can was a three dimensional world of depth stereo changes, this is so-called of stereo Visual principle. According to the theory of stereo vision, if we like our left and right eyes see two images taken at different locations, respectively, from which we should be able to feel a solid three dimensional space of two images.
From the preceding analysis, we can know the different point of view and will be able to see different images. If we place the grating perpendicular to the two eyes, due to a grating observation angle of eye, two eyes would see two different images, resulting in the icing. For best stereo I just made two images, but with a set of stereo image sequences, and given the circumstances, based on location, as long as both the two images in the sequence, you can feel the three-dimensional effect.