Detection of foreign bodies in grain with terahertz reflection imaging

Abstract

Foreign bodies embedded in grain are difficult to detect with conventional measurement methods. In this paper, terahertz time-domain spectroscopy (THz-TDS) reflection imaging is proposed as a non-destructive and deeply penetrating technique for detecting the foreign bodies found in wheat grain with different depths below the surface. Image preprocessing and threshold segment algorithm are employed to improve the THz images. In contrast to the behavior of wheat grains, foreign bodies embedded in flour are also detected and analyzed. The results indicate that the THz reflection imaging technology promises to be a useful tool for observing the presence of foreign bodies in grain.