Our living world is 3D naturally, and our human beings use eyes to percept this world, which are equivalent to stereo cameras in cyberspace. In this chapter, three concepts are introduced with the fundamental knowledge: stereo cameraStereo camera, stereo visionStereo vision, and 3D reconstruction3D reconstruction. Finally, the 3D scene is constructed by using sensors to observe this environment. The significance of this chapter is that we reconstruct the 3D scene and take advantage of stereo vision for probing robotic view.