Thin-films are the main component of many green technologies, such as solar panels or LED lights. The scientific process of measuring thin-film is photovoltaic metrology. It is used in university and commercial labs as well as in most production facilities, especially for the purpose of monitoring a variety of quality parameters such as thickness and roughness during the manufacturing of thin-film in large, industrial quantities. This in-line monitoring helps manufacturers to meet quality standards at all times. This real-time approach also keeps cost down, because anomalies can be discovered and corrected before large quantities of materials are wasted.