Night vision means that you will be able to see in total darkness. Whether you are being biological or technical, night vision is made possible by a combination of two approaches: sufficient intensity range and sufficient spectral range. Animals have better night vision than humans, partially because human eyes do not have a tapetum lucidum. Active infrared night vision merges two things. They are infrared illumination of spectral range 700nm-1000nm, which is just a bit further than the visible spectrum of the human eye, with specially designed CCD cameras sensitive to infrared light. The final result appears on a normal display device as a monochrome image. To a human observer this result is darkness. Since active infrared night vision systems can incorporate high level of infrared light illuminator, the results are normally a higher resolution than other types of night vision technologies. Active infrared night vision is found in many common places these days. It is found in commercials as well as in government and residential security applications, or anywhere else it can provide effective night time viewing under any low light environment. Active infrared light can be detected by night vision goggles so it is not used or needed in tactical military operations or anywhere else these goggles may be used. A night vision device, or an NVD, comprises an IR image intensifier tube in a rigid casing. This is often used by military forces. Night vision goggles are a type of NVD that has dual eyepieces Night Vision goggles can utilize either one intensifier tube with one image sent to both of your eyes, or two separate images intensifier tubes, one for each individual eye.