Night+Vision

=**Night Vision**=


 * Night vision** is the ability to see at night or places with low light conditions. Animals have more ability to see at low light conditions compare to humans. It is because us humans lack the presence of tapetum (a layer of tissue in the eye of multiple vertebrates) in our eyes. However, we were able to increase our ability to see in the dark with the help of technology. Different devices were made to improve our ability to see things in darkness. Night visions were made possible by the combination of two approaches: sufficient spectral range, and sufficient intensity range.

1. Types of Range 1.1. Spectral range 1.2. Intensity range 2. Night vision technologies 3. Relation to light or optics 4. Application/How it works 5. Video about Night Vision

Types of Range
These ranges enhances our vision when enhanced or improved. Ranges vary among animals and humans due to disimmilar components of the eyes.

__Spectral range__

 * Spectral range** techniques able the viewer to see different types of light that are invisible to humans. Humans' vision is limited only to a small portion of electromagnetic spectrum called visible light. However, with enhanced spectral range, it ables us to see non-visible sources of electromagnetic radiation (such as near-infrared or ultraviolet radiation). Unlike humans, there are animals that requires more infrared or/and ultraviolet spectrum.

__Intensity range__

 * Intensity range** is the ability of being able to see things with low light. Humans have less ability to see at night or at dark compare to other animals like dogs and cats because of the difference between their eyes. Some animals have unique characteristics or parts in their eyes which ables them to see in the dark naturally (one of these is tapetum, which was said earlier). However, with the help of technology, humans are able to enhance their intensity range which gives them more ability to see at darkness.

Night Vision Technologies
Night vision technologies can be basically divided into three different categories: __**Image Intensification**__ Technologies in this category aid us to see in the dark by enhancing the amount of received photons from various natural sources such as moonlight and starlight. Examples of technologies in these category are low light cameras and night glasses __**Active Illumination**__ Active illumination technologies work by coupling imaging intensification technology with an active source of illumination in the near infrared (NIR) or shortwave infrared (SWIR) band. Example from this category is low light cameras. __**Thermal Imaging**__ Thermal imaging technologies work by determining the difference of temperature between the background and the foreground objects. Example from this category is thermal imaging camera

Relation to Optics
Night vision is obviously related to optics because it is about seeing things at night or with low amounts of light. Optics is the branch of physics which involves the study the behavior and properties of light and how we see them. It is also related to our eyesight/vision. Therefore, night vision is truly related to optics since it is about seeing light at night or at dark places.

Application
As said earlier, night vision was made possible by enhancing our spectral and intensity range which gives us the ability of seeing with low amount of light. In animals, some of them have the tapetum which is located in the back of the eye which made them able to see at night. You can acquire night vision with the help of technology or through natural means like animals.

Video
Here is a video which compares night vision cameras and thermal imaging. media type="youtube" key="rAvnMYqj2c0" height="315" width="560" align="center"

-Carlo