A Methodology for Non Destructive Reconstruction of Multilayer PCBs Using Thermal Waves

This paper proposes a new active thermogra-phy methodology for the non-destructive investigation and reconstruction of internal structures in multilayered printed circuit boards through the digital image processing of superficial thermal records. The methodology relies on the sequential composition of three digital signal processing techniques standing for the raw-data signal reconstruction, the transformation of the thermal information in a virtual acoustic wave, and the virtual wave analysis for the source spatial reconstruction. The methodology is validated through finite element simulations which proves that this imaging methodology is capable of localizing and reconstructing the shape of the traces. The main novelty is the application of a recent new algorithm for thermal imaging for the monitoring of internal traces in multilayered printed circuits and the design-from-PCB.