Microwave phase-locked thermal imaging system and method

The invention discloses a microwave phase-locked thermal imaging system and method. The method comprises the following steps: periodically heating a detected object by adopting continuous microwaves subjected to amplitude modulation by a periodic phase-locked signal, generating thermal waves with periodic change inside the detected object, and recording a temperature signal with the periodic change on the surface of the detected object by adopting a thermal imager, wherein the temperature signal can reflect thermal wave abnormality caused by defects; setting a reference signal according to the phase-locked signal or a temperature signal without a defect area; performing fast Fourier transform on the temperature signal and the reference signal, and extracting the amplitude and the phase of specific frequency such as phase-locked frequency as characteristic values; performing phase-locked association on the temperature signal and the reference signal, and extracting the amplitude and the phase of the phase-locked frequency as characteristic values; and performing reconstruction imaging on the characteristic values of all pixel points of a detected area. The method and the system have the advantages of high signal to noise ratio, capacity of suppressing the emissivity change, large detection depth and the like and can be widely applied to the fields of nondestructive testing, medical imaging, target detection and the like.