It was when the Second World War broke out that night vision technology was first utilized. It came as night glasses with 56-mm diameter lenses and seven to eight times magnification. Many decades later, infrared waves were applied to night vision technology. This article identifies the differences and similarities between night vision vs infrared.
The information contained here is especially necessary when purchasing a night vision device. Everyone should be aware that there are two primary options for night vision technology: light-dependent and temperature-dependent.
Night vision refers to the technology that enables humans to see objects or scenes in low-light conditions. It is made possible by two approaches: sufficient intensity range and sufficient spectral range. Night vision also refers to the natural ability to see or live in the dark.
The naked human eye does not have enough rods and cones in the retina to detect movement and see colored light in the night. However, some creatures, such as tarsiers and cats, have more rods and more prominent pupils to allow more light to enter through their retina.
Meanwhile, infrared is a kind of electromagnetic radiation with extended wavelengths. It is invisible to the human eye, but the wavelengths up to 1050 nanometers can only be seen under particular circumstances. Similar to night vision, infrared is also utilized for surveillance, night monitoring, and tracking.
Although they are called cameras, they are actually sensors. To understand how they work, you first need to forget everything you know about how cameras take photos.
Light and heat are both parts of the electromagnetic spectrum. A regular camera that detects light will not see thermal energy, and the same is true for a thermal camera; it won’t catch the light. Thermal cameras take photos from the heat bounced off by the surrounding objects, not from the available light.
The thermal waves may come from combinations of various sources in the area being monitored or captured. They may come from engines and machines that emit heat mechanically, or from warm-blooded animals, including humans. Some objects, such as stones, vegetation, and buoys, absorb heat during the day and emit it off during the night.
Aside from heat, a thermal camera also determines the variances in temperature even as little as 0.01 degrees Celsius. It can show this difference as shades of grade in a black and white video. Some concepts of thermal cameras are hard to comprehend. However, modern thermal cameras are much easier to use than light-dependent cameras like DSLRs.
The green images or videos seen in movies and computer games come from night vision devices that utilize night vision technology. As stated earlier, these devices capture the light, amplify it, and show it on the monitor or display.
Similar to the human eye, night vision devices (NVDs) are limited to the lack of light. The quality and clarity of images taken using NVDs depend on the quantity and strength of the reflected light. Hence, taking photographs during the twilight hours is not ideal because there is too much light.
The comparison between night vision vs infrared can be shown in night vision goggles. Initially, these devices work by gathering any meager amount of light available in the surroundings and amplifying this light so that the naked eye can recognize it. Among its primary applications are military and surveillance.
Infrared is the newest technology applied to night goggles. Instead of light, these goggles depend on the infrared waves produced by any heat-emitting objects. The contrast in temperatures among the objects provides the identification of each object in the dark.
Since night vision goggles rely on the available light that reflects off of objects, the absence of light means no amplified image. In contrast, infrared goggles do not depend on light, so they don’t encounter a similar issue. As objects produce infrared light, infrared goggles can always reflect an image in any low-light condition.
In most cases, infrared light is better than night vision goggles because infrared goggles can recognize objects that are totally or partially hidden. For example, if a person hides inside a box, a night vision goggle will not be able to see him. In infrared technology, the body heat of the person will penetrate through the box and will be seen in the infrared device.
Infrared and night vision devices both function well in many applications. If you are torn between the two, here are several factors that you need to consider:
Remember that night vision devices depend on the light source. If you monitor or hunt in areas where natural light is not available, infrared devices may be the more suitable choice.
Being aware of the climate before-hand will help you make a wiser decision. Will you install the device in front of your gate? Will you be hunting in thick bushes? Is the area foggy? In these situations, an infrared device is probably the better option.
On the other hand, infrared devices will not work in a cold environment. Since there is a lack of heat, thermal optics will not be able to produce an image. Icy conditions affect the quality of the image or footage.
For most people, the cost of a device is a significant consideration. Generally, night vision devices are a lot cheaper than the infrared devices. They also come with additional features such as colored display and zooming capacities. The more features a device has, the more likely it will be more expensive.
Night vision devices are generally cheaper than infrared devices. However, they have some disadvantages: they need enough light source and enough contrast to capture a good image in low-light conditions. They are also not ideal for capturing pictures or footages during twilight hours or dawn.
On the other hand, infrared or thermal devices tend to be more expensive. However, they have more advantage in capturing images in any light condition, day or night. They generate their own contrast.
In conclusion, we have found that infrared devices are the better option when it comes to monitoring or taking footages in the dark or low-light conditions.