We able to see color because The retina of our eye is covered by millions of light sensitive cells, some shaped like rods, and some like cones.
There are three types of cone – shaped cells , each sensitive to the long, medium, or short wavelengths of light which represent the colors red, green, and Blue. These cells, working in combination with connecting nerve cells. Give the brain enough information to interpret and name colors. In short, the human eye and brain together , translate light into color.
People who have to work in the dark often were night vision goggles. These goggles are designed on the principle that even in pitch darkness, there is some reflected light, which be cannot normally see. Moreover, all object give off ‘ Heat’ energy, which is not visible to the human eye. Night vision goggles are designed to collect and amplify all those tiny bits of available light so that our eye have enough light to see in the dark. This is called image enhancement technology.
The other technology used in night vision equipment is called terminal imagine. It takes advantage of infrared light given off by object, which is not visible to human eyes.