Thermal Night Vision Devices

Thermal Night Vision Devices

In certain cases when you are sitting in total darkness, you may consider having thermal and night vision devices. Thus, later, when going to the specialized store the variety of available options will definitely confuse you. As a result, nothing will be bought. Thus, you should prepare for such a purchase in advance. So the below information will help you to know more about such a tricky device.

What types of night vision are there?

It’s obvious that night vision technology allows us to see in total darkness without an auxiliary light. However, the principle of the work of modern products differs a lot. Let’s have a look at each method more closely.

  1. The simplest devices are those that use image intensifier. It comes in the form of a vacuum-sealed tube. And, its principle is based on magnifying the emittance of photons from natural sources such as the moon or stars. Then, it renders the image, even if the amount of photons is limited.
  2. The next is an upgraded version of the previous method. Or, more correctly, using the image intensifier in a conjunction with the active source of light. In other words, both technologies work together simultaneously. Thus, there is supposed to be a special device that produces infrared waves and a camera that is sensitive to such radiation. Altogether, they produce a more precise picture than it was with the previous method. The alternative to the IR could be a laser. However, it required an additional range gate controller that adjusted the laser impulses so the camera can catch them.
  3. The advanced version of night vision devices is those that are thermo-sensitive. In particular, there is a camera that recognizes an infrared emittance from objects and renders the high-precision image as a contrast of ambient and object’s temperature.

Why is the thermal imaging night vision principle better?

The thermal imaging night vision principle is a way better than the predecessors. It’s because of their huge drawback that they required additional light sources to render the image. As a result, they either produce a low-precision image or come with an additional device that makes the whole unit heavier and bulky.

Meanwhile, the thermal night vision camera produces fine or, even, HD pictures. The quality of the image doesn’t depend on the ambient light, so there doesn't need to be additional equipment. Moreover, unlike the other methods, this one allows you to see the minimal temperature changes even though the obstacles such as rain, fog, etc.

How far can you see with thermal night vision devices?

Despite the fact that night vision with thermal overlay provides high-resolution pictures, the result that you may expect may be absolutely terrible. Thus, there occurs the question, how far does the night optics thermal camera see.

In fact, there is no particular answer. The reason is that there are lots of variables that influence the result. The main is the lenses, the type of camera, weather conditions, the size of the object, etc. That is why there was developed a list of criteria that helps to define how good the comprehension is. The author was a scientist in chief of Night Vision and Electronic Sensors — John Johnson.

The first stage is “detection” which refers to understanding whether the object is present or not. In order to do that, the object should be covered at least with 1.5*1.5 pixels.

Lens Target 320*240 pixels cameras 640*480 pixels cameras
9mm Human 205m  
Vehicle (min 2.5m long) 590m  
13mm Human 300m 390m
Vehicle (min 2.5m long) 840m 1.08km
19mm Human 450m  
Vehicle (min 2.5m long) 1.3km  
25mm Human - 820m
Vehicle (min 2.5m long)   2.2 km
35mm Human 780m  
Vehicle (min 2.5m long) 2.15km  
50mm Human 1.0km  
Vehicle (min 2.5m long) 2.6m  
65mm Human 1.45km  
Vehicle (min 2.5m long) 3.9km  
100mm Human 2.1km  
Vehicle (min 2.5m long) 5.3km  

The second stage is “recognition” which refers to understanding what this object is. In particular, whether it is a person, animal, or vehicle. For this purpose, the object should be subtended by at least 6 pixels

Lens Target 320*240 pixels cameras 640*480 pixels cameras
9mm Human 52m  
Vehicle (min 2.5m long) 150m  
13mm Human 74m 95m
Vehicle (min 2.5m long) 215m 275m
19mm Human 112m  
Vehicle (min 2.5m long) 330m  
25mm Human   210m
Vehicle (min 2.5m long)   580m
35mm Human 190m  
Vehicle (min 2.5m long) 560m  
50mm Human 250m  
Vehicle (min 2.5m long) 700m  
65mm Human 370m  
Vehicle (min 2.5m long) 1.0km  
100mm Human 540m  
Vehicle (min 2.5m long) 1.5km  

The “identification” stage means that the object is not clearly seen yet but it’s possible to understand who is in front of you by recognizing particular things. In order to do that, the object should be subtended by a minimal scope of 12 pixels.

Lens Target 320*240 pixels cameras 640*480 pixels cameras
9mm Human 26m  
Vehicle (min 2.5m long) 74m  
13mm Human 37m 47m
Vehicle (min 2.5m long) 108m 14m
19mm Human 56m  
Vehicle (min 2.5m long) 165m  
25mm Human   104m
Vehicle (min 2.5m long)   290m
35mm Human 97m  
Vehicle (min 2.5m long) 280m  
50mm Human 128m  
Vehicle (min 2.5m long) 350m  
65mm Human 170m  
Vehicle (min 2.5m long) 530m  
100mm Human 270m  
Vehicle (min 2.5m long) 760m  

As it was already mentioned, these digits are approximate. Because there may be lots of obstacles that will distort the final result. Thus, these tables are just a recommendation for potential users.

What available forms of thermal night vision devices are there?

The thermal night vision devices are now digital-only. However, there is a huge variety of shapes and forms. In particular, there can be thermal night vision goggles or binoculars. At the same time, the monoculars, or tubes, are also popular among users. On a separate note, there can be stationary thermal overlay night vision cameras attached to the buildings, too.

What are thermal night vision goggles with heat sensor used for?

Luckily, thanks to technical progress, now we can have unbelievable skills. For example, thermal imaging goggles with night vision allow us to have an animal’s sharp sights. So, so now, people can go on hunting at night without any difficulties.

However, still, the major consumer of night-vision goggles with heat sensors is the military. This is an effective instrument against illegal migration at the borders that usually intensifies at night, and, against potential enemies.

Meanwhile, the civilians also apply thermal night vision glasses at work. For example, it’s quite important to use such devices when building. Or, this is an irreplaceable thing in rescuing people or firefighting.

Besides, there may occur an idea of where thermal night vision can be applied. And you may need a reliable partner who can bring the abstract into life. Then, it’s better to drop a message to the Axonim company, who can do it really quickly and with no fuss at all!

Read in Russian: проектирование и конструирование электронных устройств в Аксоним

Back to the list of articles
1