When it comes to ratios, we can only know the exact proportion by measurement, or, precise measurement. The related study and activities of measuring is generally called “Metrology”.
One of the most common filed is surface measuring. The more precise the ratio you want, the better equipments you will need. Especially for the roughness surface measurement, it is difficult to detect any detail angle by using a random machine. The optical profiler, on the other hand, providing a better working place and measuring result for the technicians. Before the appearing of non-contact measurement, the metrologists use the traditional profilometer, which is a device to measure the surface by contacting the object. With the invention of non contact profiler, the different usages are separated to meet the needs. If you are looking for quick and precise measurement, and at the same time avoid the careless damage to the device, the new measuring equipment might be your first choice.