<P> Night - useful spectral range techniques can sense radiation that is invisible to a human observer . Human vision is confined to a small portion of the electromagnetic spectrum called visible light . Enhanced spectral range allows the viewer to take advantage of non-visible sources of electromagnetic radiation (such as near - infrared or ultraviolet radiation). Some animals such as the mantis shrimp can see using much more of the infrared and / or ultraviolet spectrum than humans . </P> <P> Sufficient intensity range is simply the ability to see with very small quantities of light . </P> <P> Many animals have better night vision than humans do, the result of one or more differences in the morphology and anatomy of their eyes . These include having a larger eyeball, a larger lens, a larger optical aperture (the pupils may expand to the physical limit of the eyelids), more rods than cones (or rods exclusively) in the retina, and a tapetum lucidum . </P> <P> Enhanced intensity range is achieved via technological means through the use of an image intensifier, gain multiplication CCD, or other very low - noise and high - sensitivity array of photodetectors . </P>

Which ray are used to see object in fog