Can infrared thermal imaging penetrate walls and partitions to see people?

Can infrared thermal imaging penetrate walls and partitions to see people?


At present, science and technology are constantly advancing, and technological products are changing with each passing day. In recent years, infrared thermal imaging night vision devices have been widely used in civil fields with an increasing trend in nature observation, outdoor hunting, outdoor adventure, security and theft, marine operations, night patrols and other occasions! Infrared thermal imaging can be seen clearly in a dark environment due to its special performance in principle and can clearly find high-temperature targets!

Infrared thermal imaging camera has the characteristics of not being interfered by low illuminance and strong sunlight, and can penetrate smoke and haze. You can see from the above that thick clothes cannot be penetrated, so don't worry about your privacy. Infrared thermal imaging camera realizes imaging of objects by collecting the thermal radiation of different objects, so that it can be reflected by certain materials less than visible light, and can pass through thin and thin fabrics and be reflected back by objects hidden under the fabric. Through the fabric, some special fabrics (pure nylon and silk) can be made translucent, but the perspective effect is relatively limited.

The principle of infrared thermal imaging is similar to that of a camera, except that the difference is in the infrared wavelength band that is longer than the wavelength of visible light. That is, like visible light, infrared rays travel in a straight line without turning, and naturally they will not spread when the wall is blocked, and there is no penetrating through the wall to see people. All objects above absolute zero emit infrared radiation, and the radiation emitted by each band is different depending on the temperature. According to the law of black body radiation, the frequency spectrum at different temperatures:

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Infrared is a part of these electromagnetic waves. Together with visible light, ultraviolet rays, X-rays, gamma rays and radio waves, it forms a complete and continuous electromagnetic spectrum. As shown in the figure above, electromagnetic radiation with a wavelength range of 0.76μm to 1000μm is called infrared radiation. Any object whose temperature is higher than absolute zero (-273.15°C) is constantly emitting infrared radiation (thermal radiation). It is invisible to the human eye, and the wavelength of external radiation is different at different temperatures. For the human body, the body temperature is relatively constant (specific content: anal temperature: 36.6°C~38°C; oral temperature: 35.5°C~37.5°C; armpit temperature: 34.7*C~37.3°C; cochlea Temperature: 35.8°C~38°C; forehead temperature: 35.8°C~37.8°C). Thermal imaging measures the temperature by detecting the thermal radiation on the human surface. Based on the big data of human body temperature measurement, it is mapped to the internal temperature of the human body through a temperature measurement algorithm.

The infrared radiation in daily life is about 300K to 500K, that is, the main radiation frequency is 1μm to 10μm.

However, comparing the penetration of most glasses, it can be found that the penetration has been greatly reduced at around 2.2μm.

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That is, to see things through glass, the working wavelength of the infrared camera should not be higher than 3μm at least.

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For infrared cameras that work in the MWIR and LWIR bands, the glass is opaque to it, just like a wall. Only infrared cameras in the SWIR band can see people through the glass.

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Can infrared thermal imaging penetrate walls and partitions to see people?-Safeagle

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