Active thermal NDT is a promising technique for the detection of structural defects in solids. In this paper, the results of the first-stage research devoted to infrared thermographic detection of cracks in titanium alloys are presented. The test results obtained show that the Fourier analysis is a convenient data processing technique in active thermal NDT. Images of phase are more noise-resistant and able to reveal deeper defects compared to images of amplitude. In application to the inspection of bottom-hole defects in 9.6 mm-thick Ti6Al4V titanium alloy samples, it has been found that a minimum detected defect should have diameter from one to two times greater than its depth.