3-D holograms will be employed for battlefield intelligence, military planning and explosives disposal

We see things because our eyes are sophisticated light detectors: they constantly capture the light rays bouncing off nearby objects so our brain can construct an ever-changing impression of the world around us. When our eyes see a three-dimensional image such as apple, Light reflects off the surface of the apple into two eyes and your brain merges their two pictures into a single stereoscopic (three-dimensional) image. If you move your head slightly, the rays of light reflected off the apple have to travel along slightly different paths to meet your eyes, and parts of the apple may now look lighter or darker or a different color.