Most people typically think of low-light amplification technology when they think of night vision (this is the type of night vision that has that green glow to it). Essentially, it is able to intensify minimal ambient light (even from the stars and the moon) and is purposefully tinted green because our eyes are more sensitive to green light. Active night vision, on the other hand, is used mostly by commercial and residential security applications. Unlike both active and passive night vision, thermal technologies do not need any light (infrared or visible) to construct visible images. Instead, they sense minute differences in temperature levels. This technology is now being used in military, firefighting, law enforcement, medical, and security fields.