X-ray inspection is used to detect foreign objects and to identify quality issues during production. It works by detecting contaminants or defects on the basis of variation in density from the standard product. Inspection systems based on X-rays can also be used to detect the fill level in opaque containers and to locate air bubbles, breakage and other manufacturing defects. Choosing a suitable X-ray inspection system requires consideration of the physical form of the product, the type of product container, desired sensitivity, production line speed, and the specific inspection objectives.