  Inspired by the extensive application of terahertz imaging technologies in
the field of aerospace, we exploit a terahertz frequency modulated continuous
wave imaging method with continuous wavelet transform algorithm to detect a
multilayer heat shield made of special materials. This method uses the
frequency modulation continuous wave system to catch the reflected terahertz
signal and then processing the image data by the continuous wavelet transform
with different basis functions. By calculating the sizes of the defects area in
the final images and then comparing the results with real samples, a novel and
practical high-precision terahertz imaging method are demonstrated. Our method
can be an effective tool for the terahertz nondestructive testing of
composites, drugs and some cultural heritages.
