The difference between night vision device and thermal imaging device

2020-10-29

Night vision device is our traditional infrared low light level night vision device. This kind of night vision device amplifies the signal through an image intensifier and converts the low light level information into visible information. Therefore, in principle, it needs a light source. In the case of total darkness, if there is no infrared auxiliary light source, the target cannot be seen. Passive night vision device is a thermal imaging night vision device, which produces visible images through the principle of thermal imaging. Thermal imaging night vision device does not need light source, only need to observe the temperature difference of the object. It is necessary to make use of starlight and moonlight, but to make use of the difference of thermal radiation. The brightness of the screen indicates that the temperature is high, and the dark place indicates that the temperature is low. The infrared thermal imaging night vision device with good performance can reflect the temperature difference of one thousandth of a degree. Therefore, it can find vehicles, personnel and even buried objects hidden in trees and grass through smoke, rain, snow and camouflage. Many people have been choosing night vision devices, but they have been unable to choose between infrared night vision devices and thermal imaging night vision devices. What kind of night vision devices should they choose and which night vision devices work well? I believe you should have some understanding after reading the following.

In terms of classification, night vision devices can be divided into two categories: image enhancement tube night vision devices (traditional night vision devices) and infrared thermal imaging night vision devices.
1、 The imaging principle of infrared thermal imaging night vision device and infrared low light level night vision device.
Basically speaking, ordinary infrared night vision device is called active night vision device, and infrared thermal imaging night vision device is called passive night vision device. From the literal understanding, we know that the target of ordinary infrared night vision device, which is an active infrared night vision device, needs light. Therefore, the traditional name is low light level night vision device. Its principle is that the weak light of the target is amplified into the light that can be observed by the human eye through its internal core component image intensifier. Therefore, this kind of active night vision device can not see any target in the case of all black, so this night vision device is equipped with infrared transmitter, in the case of all black, the invisible infrared lamp is used to irradiate the target to make the target visible. However, the passive thermal imaging night vision device is totally different from the former. It uses infrared detector, optical imaging objective lens and optical mechanical scanning system (the advanced focal plane technology omits the optical mechanical scanning system) to receive the measured target

The infrared radiation energy distribution pattern is reflected on the photosensitive element of the infrared detector. Between the optical system and the infrared detector, there is an optical mechanical scanning mechanism (the focal plane thermal imager has no such mechanism) to scan the infrared thermal imager of the object to be measured, and focus on the unit or optical detector, and the infrared radiation energy is converted into electricity by the detector The signal is amplified and converted into standard video signal, and the infrared thermal image is displayed on the TV screen or monitor. This kind of thermal imaging night vision device, in all black and daytime observation target is exactly the same, without the influence of light.


1. Infrared low light level night vision device is the infrared low light level night vision device, which can be divided into one generation to four generations according to the generation of image intensifiers. Because the first generation night vision device can not meet the needs of people in terms of image brightness enhancement and clarity. Therefore, in foreign countries have rarely seen a generation and a + night vision device. Therefore, if you want to achieve real use, you need to buy the second generation and above image tube night vision device.

2、 Difference of observation effect between infrared thermal imaging night vision device and infrared low light level 2 + night vision device

The field of view of infrared LLL night vision device is round, and that of thermal imager is square. If you have used the ordinary digital night vision device, you will find that the observation feeling of the digital night vision device is completely different from that of the ordinary infrared night vision device. This is because the general infrared night vision device directly observes the target through the lens, so the field of view is as round as the telescope. The digital night vision device is electronic. In fact, what your eyes see is the image on the internal LCD screen, rather than directly seeing the target, so the field of view is square. Thermal imaging night vision device is the same as digital night vision device in this respect. Whether it is hand-held thermal imaging night vision device (liquid crystal screen is outside the machine) or telescope type thermal imaging night vision device, the field of vision is square. It is not to directly see the target, but to see the image on the LCD screen. So thermal imagers are all digital.


The effect of ordinary digital night vision device can not be compared with thermal imager, nor can it be compared with ordinary night vision device of generation 2 +. But the effect of the third generation digital night vision device is the real Three Generation night vision device, and the viewing field is the same as that of the thermal imager. The display effect is different between the two.


1. Generally speaking, the imaging of ordinary generation 2 + infrared night vision device is green, more like positive effect. The thermal imaging night vision system is colorful.


Therefore, from this point of view, you can choose the instrument suitable for your own use.

Generation 2 + night vision device can see who this person belongs to. In terms of effect, the observation effect of different brands of the second generation infrared low light level night vision device is very different.