Metrology-MSA (measurement system analysis) measurement system: it is a collection of operations, procedures, measurement tools, software, operators and environments used to assign values to the measured characteristics; The whole process for obtaining measurement results.
Ancient Metrology: Metrology was called "Metrology" in the history of China. In ancient China, a certain part of the human body or the fruits of other natural objects and plants were taken as the standard of measurement, such as "measuring by hand", "lifting", "focusing on strength", "measuring by stepping on an acre of land" and "measuring by dripping water".