Digital vs Thermal Night Vision

Graphics of Digital vs Thermal Night Vision comparison

Night vision is where you can see in low light conditions or complete darkness. Humans use devices such as night vision monoculars, binoculars and scopes to see in the dark. This is because our eyes are very limited in seeing in the dark. There are two types of nigh vision; Digital Night Vision and Thermal Imaging Night Vision. Continue reading to find out the differences between Digital vs Thermal Night Vision and what purposes you can use them for.

Digital Night Vision

Digital night vision devices use a CCD or CMOS sensor to convert an optical image into a electrical signal by collecting incoming light. Then, the sensor enhances the image and gives the pixels a digital value. Finally, the sensor coverts the signal into an image, displaying it on a LCD or OLED screen. Digital night vision devices can generally see distances of up to 300 meters. They can also identify certain details or characteristics of an object such physical features or gender. The quality of the image, however, is dependent on how good the sensor is.

Graphic of midnight Optics Explorer digital night vision binoculars

Midnight Optics Explorer

Digital night vision devices come with various colour palettes. The most common palette is black and white. This shows night time images in a black and white gray scale, allowing the brain to pick up specific details of the object. You will also find green is another common palette. It brings out more detail in objects. This leads to increased detection and detail recognition. With different devices you will get specific colour palettes. For example the Midnight Optics Explorer has a purple viewing mode. Likewise the Sionyx Aurora Black has full colour night vision mode.

Graphic of grey colour palette from Midnight Optics Explorer
Graphic of Green colour palette from Midnight Optics Explorer
Graphic of Purple colour palette from Midnight Optics Explorer

Observing a cat with the three colour palettes of the Midnight Optics Explorer

Thermal Imaging Night Vision

The second category of night vision is thermal night vision. These devices use an infrared sensor to identify the differences in heat signatures of targets. Then, the sensor transfers this information into a viewable image image on an OLED screen. High heat signatures will appear to be yellow, red or orange in colour.

A major factor that determines the effectiveness of thermal devices are the pixel resolution, pixel pitch and NETD or the sensor. Pixel resolution determine the image quality and the bigger the pixel resolution the better the image quality. A pixel resolution of 640×480 will yield high-definition images. Pixel pitch refers to the distance between the centers of two pixels. It is measured in microns (µm) and the lower the value the better the sensor performs. Similarly, Noise Equivalent Temperature Difference (NETD) measures how effective a thermal sensor is at identifying temperature differences. NETD value will be expressed in milli-kelvins (mK). Just like Pixel Pitch, the lower the value the better it performs. For example, a thermal device with 12 µm and a NETD <25mK sensor is ideal. This is because it can pick even the smallest temperature differences even in harsh weather conditions. It will also generate a high quality image which makes detection and detail recognition easier.

Graphic of HIKMICRO Thunder Pro TE25 thermal nigth vision monocular and mountable scope.

HIKMICRO Thunder Pro TE25

Another outstanding feature of thermal night vision are the colour palettes. The different palettes aren’t just a filter, but serves to further enhance the image and bring out detail. The most common palettes are white hot, black hot, red hot and rainbow. These are ideal for object detection and detail recognition. Other palettes include ultramarine, sepia, red monochrome and violet which are suitable for long night time observations.

Bellow shows images taken from the Hikmicro Thunder TE25

White Hot

Black Hot

Red Hot

Rainbow

Uses For Digital Night Vision

Digital night vision can be integrated for a variety of different uses. It aids law enforcement and security personnel to identify persons of interest at night and perform surveillance operations. First responders can rely on them to perform night time search and recue operations and hunters can use them to spot targets.

Uses For Thermal Night Vision

Thermal devices are ideal for outdoor use. Users can mount them on cars when driving through rough terrain or hiking at night time. You can also use them for wild life detection such as hunting or looking for a lost pet. Due to the sensor being able to pick up small temperature differences, detection will be seamless in heavy rain or dense fog.

In addition, firefighters use thermal devices, such as thermographs, to detect fires of high temperature areas. Likewise, Law enforcement can rely on them to identify suspects or heat signatures of concealed firearms.

So Which Is Superior?

Both devices allow users to see in the dark and each have their strengths and weaknesses. Digital night vision is generally more affordable than thermal devices and gives a more natural image. They are also more durable as the sensor wears slowly over time. However, smoke can obstruct a clear image which will hinder the ability of users to spot targets. Users may also experience lag due to frames are refreshing when a viewing a moving target. Moreover, these devices require a source of light to work. If there is no source of light, it will rely on the IR illuminator which drains the battery.

On the other hand, Thermal devices are masters of detection. They can detect small temperature differences to identify live objects. Some devices even have detection ranges over 2000 meters which increases the chances of spotting a target. Furthermore, thermal devices can be used at any time of day and generate higher quality images. Nevertheless, there are some drawbacks. Thermal devices are generally more expensive than digital night vision. You also will not be able to see through glass or water and they tend to be heavier as well.

Conclusion

the differences between Digital vs Thermal Night Vision are important to consider as they are two uniquely different devices. Each device can be optimised for different tasks and both have advantages and drawbacks. However, both devices will allow you to see in the dark.

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