The difference between thermal imaging camera and night vision device
One, image intensifier tube night vision device
In terms of classification, night vision devices can be divided into two categories: image intensifier tube night vision devices (traditional night vision devices) and infrared night vision thermal imagers.
Active night vision devices such as ordinary infrared night vision devices require light for the target, so they are traditionally called low-light night vision devices. Light that can be seen by the eye. In total darkness, no target can be seen, so this night vision device is equipped with an infrared transmitter, which uses invisible infrared lights to illuminate the target in total darkness to make the target visible.
According to the algebra of image enhancing tubes, night vision devices can be divided into one to four generations. Because the first generation of night vision devices cannot meet people's needs in terms of image brightness enhancement and clarity. Therefore, it is rare to see first-generation and first-generation + night vision devices abroad. If you want to achieve real use, you need to buy a second-generation and above image-increasing tube night vision device. In the traditional second-generation and above night vision devices, the well-known brands are ORPHA and ASI. These two brands have a common background of developing top-of-the-line night vision products with the US and NATO military.
Two, infrared night vision thermal imager
Basically, thermal imaging night vision devices are called passive night vision devices. The passive thermal imaging night vision device uses infrared detectors, optical imaging objective lenses and optical-mechanical scanning systems (the current advanced focal plane technology omits the optical-mechanical scanning system) to receive the infrared radiation energy distribution pattern of the measured target and reflect it into the infrared image. On the photosensitive element of the detector, between the optical system and the infrared detector, there is an optical-mechanical scanning mechanism (the focal plane thermal imager does not have this mechanism) to scan the infrared thermal imager of the measured object and focus on the unit or On the spectroscopic detector, the infrared radiation energy is converted into an electrical signal by the detector, which is amplified and converted into a standard video signal to display the infrared thermal image on a TV screen or monitor. This kind of thermal imaging night vision device observes the same target in total darkness and daytime, and is not affected by light.
At the end of the last century, with the development of thermal imaging technology, due to the technical advantages of thermal imaging technology over traditional night vision devices, the US military gradually began to equip infrared night vision thermal imagers. Infrared night vision thermal imagers have been continuously developed in the past 10 years, and the cooperation between RNO and the US military has also promoted the development of infrared night vision thermal imagers in civilian applications. RNO, a well-known military enterprise in the United States, can be said to have contributed a lot.
The difference between Three, night vision and thermal imager
1. Effectiveness and effect
1) If you have used ordinary night vision devices, you will find that the observation feeling of night vision devices is completely different from ordinary infrared thermal imagers. This is because the general night vision device directly observes the target through the lens, so the field of view seen is the same as that seen by the telescope lens, which is circular and the picture is green. If the clarity is enough, it is possible to identify who the target of the character is and to see the facial features of the person clearly.
2) The infrared night vision thermal imager sees the image on the internal LCD screen instead of seeing the target directly, so the field of view is square. The imaging of the infrared night vision thermal imager will be based on the temperature distribution. The higher the temperature, the brighter the brightness. On the contrary, the lower the temperature, the darker the color. The main purpose is to find the target and identify the target category, such as the target is a person, an animal, etc.
2. The influence of light factors
1) The second-generation + night vision device is greatly affected by the environment due to the imaging principle. Especially under the influence of light, when the light is dimmed, the observation distance will be shortened. In the case of total darkness, the auxiliary infrared light source must be used, and the distance of the auxiliary infrared light source is generally only up to 100 meters. At the same time, they will also be afraid of strong light, although many traditional night vision devices have strong light protection. However, if the ambient brightness changes greatly, it will have a great impact on the observation.
2) Infrared thermal imaging night vision device will not be affected by light. Whether it is day or night or rainy, snowy or foggy days, the target object can be clearly observed. It is for this reason that top car night vision devices, such as Mercedes-Benz and BMW, use infrared thermal imagers.
