The invention relates to a non-destructive detection method of pulse-excited
infrared thermal wave phase of a fixed viewing field. The non-destructive detection method comprises the following steps: comprehensively applying a multiple-modulation
Zoom-FFT refining spectrum method, a thermal-wave data fitting
extension method and a zero-phase
digital filter method, and carrying out high-accuracy
spectral analysis on acquired continuous equally-spaced
infrared thermal-wave image sequences before and after thermal excitation, thus quickly obtaining precise ultralow-frequency thermal-image
phase diagram and amplitude diagram, and further realizing detection and recognition for defects or damages of equipment. Compared with the prior art, the non-destructive detection method has the beneficial effects that not only can the acquisition frequency, the
acquisition time, the acquisition frame number and the refining degree of analysis of thermal images be flexibly set, but also the detection speed, the refining degree and the precision degree can be increased by ten times respectively, the multiplied increase of the detection effect and the detection depth of the defects also can be realized, simultaneously the requirement for
computer hardware is also reduced, so that the method is flexible in use, is especially suitable for non-destructive detection of the
infrared thermal wave on site and has a wide application prospect.