The difference between night vision and thermal vision

If you've ever wondered how animals see in the dark, or considered improving your own vision at night, you've come to the right place. In this article, we'll explore the differences between night vision and thermal vision, two fascinating technologies that allow us to see in low light conditions.

What type of night vision do animals use?

Humans are naturally equipped for daytime vision, with a retina composed of cones for detecting colored light and rods for perceiving dim light. However, our night vision remains limited. Nocturnal animals, on the other hand, have evolved special adaptations for seeing in the dark. Their pupils are often larger to let in more light, and some species have a tapetum, a natural mirror that reflects light through the retina for better perception.

How was infrared night vision invented?

The idea of ​​seeing in the dark has always fascinated inventors. Infrared night vision was developed using light amplification principles. Rather than simply focusing light, these devices transform dim ambient light into a bright image we can see.

How do night vision goggles work?

Night vision goggles amplify the available light in several stages. Light from the environment enters the lens on the front of the glasses. This light is made up of photons, which strike a light-sensitive surface called a photocathode. The photocathode converts photons into electrons, which are then amplified by a photomultiplier. These electrons hit a phosphor screen, producing a bright image of the original scene, much brighter than our eyes could perceive naturally.

Why is night vision often displayed in green?

Although ambient light contains all colors, night vision goggles typically convert this light to black and white. However, the display is often green because our eyes are more sensitive to green light, making prolonged viewing easier. Just like, early computer screens were generally green for visual comfort.

Does infrared equipment allow you to see in total darkness?

Night vision goggles, as light intensifiers, only work when there is sufficient ambient light. In conditions of complete darkness, they are ineffective. This is where thermal vision comes in. Instead of relying on visible light, thermal vision detects heat emissions from objects, allowing you to see even when light is absent.

How does a thermal image sensor work?

Thermal image sensors, used in thermal vision, detect temperature variations of objects. Hot objects emit infrared radiation, similar to light, but with a slightly longer wavelength. Thermal cameras capture this radiation and convert it into a visible image, usually in shades of green, yellow and red, to represent temperature differences.

Are there other ways to see in the dark?

In addition to night vision and thermal vision, there are other navigation and sensing technologies for seeing in the dark. Self-driving planes, ships, cars use sophisticated sensors such as radar, sonar, GPS, compasses, and lidar (a laser radar) to orient and navigate in the dark.

What is the difference between thermal imaging and night vision?

Thermal imaging relies on detecting heat emissions, while night vision amplifies the weak available light. Thermal cameras are capable of operating in complete darkness conditions, not relying on visible light, unlike night vision which requires a certain amount of light. Additionally, thermal cameras offer better ability to detect temperature differences, which can be useful in many situations, including security and surveillance.

In conclusion

Night vision and thermal vision are two distinct technologies, each with their specific benefits and applications. Night vision is ideal for use in low light conditions, while thermal vision excels in complete darkness and provides heat-based detection capabilities. The choice between these two technologies will depend on the particular needs of the user and the environment in which they will be used.