Night vision technology isn't just for the military anymore. Though the best equipment is typically affordable only for military or police use, cheaper night vision gadgets are easily obtainable for everyday citizens to turn what used to be the dark into a whole new playground.
Though some night vision equipment used for government applications also harnesses thermal imaging technology, which captures infrared light being created by heat, most merely use image or light enhancement technology. This involves collecting what little light is left in a dark area, such as starlight or moonlight on the bottom end of the spectrum of infrared light, then amplifying that light so that it can be seen.
The path from darkness to light, in scientific terms: The photons of available light are cast by an objective lens upon a image intensifier called a photocathode. Electrons are emitted from this cathode, which then multiply and become intensified by a "microchannel plate" until finally passing through a phosphor screen, which allows the viewer to see a more robust version of those original scant photons of light.
The result of consumer night vision is what is commonly known as a green output image. These images have greatly improved in vibrancy and cost-effectiveness since the technology emerged on the market in the 1950s. A person without night vision can see in the dark about 250 yards under a full moon and about 50 yards under a quarter moon. Now, with consumer-level night vision technology, that person can see 890 and 850 yards, respectively. Even with overcast skies, dimming out even starlight, night vision can let the average person see more than 200 yards away.
Depending on the quality of the camera and conscientiousness of its manufacturer, night vision binoculars can vary widely in their effectiveness. The military-model ATN PS23-4 night-vision, helmet-mounted binoculars -- sell for upwards of $11,000 (USD; November 2012) but allow for visibility of up to 200 yards in total darkness, an infrared "illuminator" component, high-resolution auto-focus, and can be dropped in water.
On the other end of the spectrum, toys like the Spy Net Night Vision Surveillance Goggles cost about $40 (USD; November 2012) -- and at least allow for about 50 feet of nighttime visibility. How much more does a brother need to torment a little sibling? Not to mention, this toy lets owners record up to 20 minutes of video or 2,000 photographic images on a USB device that allows for later access via computer or TV.
Most of the night vision goggles manufactured in 2012 retail somewhere between these two extremes, in the $200-$500 (USD) price range. Some forego buying a dedicated set of goggles anyway, and just get a video camera instead. Since the 1990s, many home video cameras have come with standard with a night vision mode. In 2009, Samsung became the first to make a cell phone capable of recording video in night vision, the SCH-W760. Night vision technology is now an integral part of many home security systems too. For upwards of $100 (USD) each, wireless cameras capable of infrared, night vision and regular spectrum capture are helping regular civilians perform surveillance on their properties with military proficiency. These wireless feeds can be monitored day or night, with motion-detection alerts, from a master terminal displayed on the laptop of a property owner who's sipping margaritas thousands of miles away.