The existing infrared imaging mainly uses the amplitude information of infrared radiation, and the basic principle of infrared phase thermal imaging is to establish the phase information algorithm model of the target infrared radiation and the distance algorithm between the target and the detector by analyzing the received target radiation signal. The model obtains the distance image of the target, and combines it with the two-dimensional image to obtain the stereoscopic image of the detected target. Infrared phase thermal imaging breaks through the previous idea of only using the amplitude information of infrared radiation, and uses the phase characteristics of infrared radiation to image, which is a new infrared imaging mechanism. The relationship between distance and phase can be derived from the following relationship between phase and distance.

D=ct

It can be obtained from the above two formulas:

In the formula, N is the number of whole cycles in the full stroke of the light wave; Δφ is the phase value of less than one cycle. If the wavelength is known, the relationship between the distance and the phase can be found. Infrared phase imaging is to use this principle to obtain the distance information of the infrared image, and combine it with the two-dimensional information of the infrared target to reconstruct a three-dimensional image.