This study utilizes infrared thermography (IRT) and terahertz (THz) imaging techniques to conduct a non-invasive inspection of marqueteries. Specifically, two experimental investigations and image processing methods have been carried out, and their advantages and disadvantages have been highlighted. To cross-reference with the experimental results, a finite element simulation was performed for both IRT and THz, which validate the experimental outcomes and providing instructions to the experimental set-up and parameters. Then, an ad-hoc fusion imaging method has been applied to the experimental results to identify defects and features. Such a reverse engineering procedure integrating numerical and experimental images acquired at different wavelengths may be considered an interesting step forward for the optimization of cultural heritage nondestructive testing (NDT).