| 摘要 |
Apparatus for determining faults in strip material is disclosed in this application which enables both color defects and distortions of the surface of the strip material to be recognized. It its general form the apparatus illuminates the material surface at a specific angle with white light and an optical system directs the light leaving the surface to a number of photodetection devices which detect the various angles at which light leaves the surface. The deviations of these angles from the direction of specular reflection, or unimpeded transmission, are characteristic of the nature of the distortion of the surface of the strip material. At least the photodetection device which receives the specularly reflected or normally transmitted light and preferably all the photodetection devices, includes two photodetectors, which detect light in different spectral ranges by means of associated beam splitting and filtering devices. In this way color defects such as stains or spots on the surface can also be recognized. |
