Preliminary Experiments for Detecting Soft Foreign Materials in Seaweed using Sub-Terahertz Radar

Abstract

Hygiene management of processed food is very important for human health. Many food manufacturers perform surface inspections for separation of food and foreign materials during manufacturing phase. However, many kinds of foreign materials are also found inside food. For this problem, a method of penetration inspection for packaged products is required. The conventional penetration inspection using X-ray and metal detector can only detect metals and hard materials while soft foreign materials such as worms, cannot be detected. In this paper, we propose a method of penetrating packaged food using sub-terahertz radar which can detect even soft foreign materials. The signal of 0.1 THz(Terahertz) frequency radar module in the proposed system can penetrate both food and foreign materials in low moisture environments. Since the signals acquired by sub-THz radar are not uniform in intensity and contain a lot of noise, we also provide a preprocessing solution to mitigate them. Through an experiment, it was proved that the worms in 100 pieces of packaged seaweed were successfully detected.