The difference between night vision and thermal imaging

(1) The working principle is different: the night vision device actively receives the light source through the image enhancement system. Until the external light source shines on the object and is reflected to the night vision device for multiple receptions, the night vision device can image. The thermal imager will not emit the light emitted by the object. Visible infrared energy is converted into a visible thermal image.

(2) Different effects: General night vision devices directly observe the target through the lens, so the field of view is the same as that seen through the telescope lens, which is circular, and the picture is green. When the clarity is sufficient, it can To distinguish a person's facial features, the infrared night vision thermal imager sees the image on the internal LCD screen, rather than directly seeing the target, so the field of view is square, and the image of the infrared night vision thermal imager will be According to the temperature distribution, the higher the temperature, the greater the brightness, and conversely, the lower the temperature, the darker the color.

(3) The influence of light factors is different: Due to the imaging principle, the second-generation night vision device is greatly affected by the environment, especially the influence of light. When the light becomes darker, the observation distance will be shortened, while the infrared thermal imaging night vision device will not. Affected by light, the target object can be clearly observed no matter it is day or night or in rainy, snowy or foggy days.

(4) Different properties: The night vision device is a nighttime external sight with an image intensifier as the core component. It does not use infrared searchlights to illuminate the target. The infrared thermal imager uses infrared thermal imaging technology to detect the infrared radiation of the target object. Detect, and use signal processing, photoelectric conversion and other means to convert the temperature distribution of the image into a visual image.

Low-light night vision equipment, also known as image intensification technology, actually enhances and amplifies the electronic signals of tiny light sources to make them visible. In an extremely low-brightness environment, the image intensifier can be used to illuminate objects with weak light such as moonlight or starlight or emit infrared detection light. The light reflected by the object is amplified by the image intensifier and converted into an image that can be clearly observed by the human eye, thereby achieving Observe the target at night. Therefore, the image intensifier tube is a key component of the low-light night vision device, and its quality directly determines the effect of the night vision device.

The real advantage of thermal imaging lies in target observation and identification. As long as the target's surface emissivity is different from the background, or it has its own temperature, thermal imaging can easily distinguish the target through the temperature difference. For example, thermal imaging in the woods can only see Even if they are covered by grass or other things, as long as a little shadow is exposed, the user can detect them with infrared and low light. It's very difficult to do.

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