Feature Article Figure 7. Vacuum level and honeycomb core pressure during ply lay-up (P) and de-bulking (D). Figure 8. Measured vacuum level and honeycomb core pressure during the vacuum hold prior to cure. Insert shows close-up of the pressure signals. Figure 9. Cure temperature and pressure data. interfaces of the coronal micro-CT images and the thermography images was observed. An example of the correlation between micro-CT and thermography images is shown in Figure 6. Satisfactory linear correlations were found between the mean grey value of ROIs at specific time stamps on the thermographs and the areal void content on the micro-CT coronal views at the three interfaces. As voids were mainly located at the ply interfaces, 14 knowing the areal void content of the three interfaces directly led to the total volumetric void content. The void content estimated from the thermography was 85% likely to predict the volumetric void content measured by micro-CT. Thus, it is possible to estimate the void content of large composite sandwich panels when considering a grid of 400 mm2 ROIs. This approach was used to estimate the voidage of the demonstrator. SAMPE Journal, Volume 52, No. 3, May/June 2016