METHOD AND APPARATUS FOR NON-CONTACT ONLINE MEASUREMENT

PURPOSE: To measure surface conditions subjected to the weight of oxide and the surface conditions of the thickness of the layer of a surface layer or the thickness of a material by a simple method based on a basis of reflection features of radiation heading for the material surface. CONSTITUTION: A measurement region, 4 on a material surface is thermally irradiated with an incident ray having an inclined angle by an infrared radiation device 2 and the temperature of reflecting thermal radiation is measured by an infrared thermometer 3. Change in the radiation measurement temperature reflected according to the surface conditions of the material is stored in a comparator 7. A set value for desired surface conditions is fed to this comparator 7. At first, the infrared ray temperature unknown of its material conditions of the surface conditions is measured so as to be compared with the stored temperature change. A differential signal which is generated from a value obtained and a set value fed in this way is fed to a control part 9 of a processor of the material via an output terminal 8 of the comparator 7.