In the past, it was necessary for inspectors to visually detect minute foreign substances that rarely got mixed in with raw materials (plants) flowing down the production line.The challenges are:1. difficult to detect visually by inspectors - It was necessary for inspectors to visually inspect foreign objects as small as 1mm, which made it difficult to detect them.2. existing inspection devices cannot cope with the problem - In addition to the fact that the foreign matter is microscopic, both the raw material and the foreign matter come in multiple types and colours and have unspecified shapes, so rule-based image inspection systems could not handle them.3. different conditions for each factory and line - The customer has multiple factories and lines, each with different types of foreign matter, different conveyor speeds, and different inspector skills.