Rapid THz nondestructive inspection of medicine capsules

In this study, we developed a screening tool for the rapid identification of defects in two-piece medicine capsules. We used THz time-of-flight (ToF) imaging by incorporating motorized rubber rollers, which allows rapid inspection of the capsules along their cylindrical surface. We obtained 3D images with the cross-sectional information, including the folded area. In particular, THz-ToF images are useful for identifying defects induced by moisture, alien substances, and holes in a nondestructive manner. The statistics for the layer thickness along capsule surfaces enable the rapid quality assessment of capsule quality, while the details on the types of defects can be determined by analyzing the 3D imaging data.