摘要 |
In an apparatus and a method for detecting impurities in a material, infrared rays or a plurality of specific wavelength components of the infrared rays are applied to a material on a conveyor, the respective reflection intensities of the specific wavelength components reflected by the material are measured, the measured reflection intensities and the reflection intensities of specific wavelength components inherent to the material are compared, and impurities in the material are detected according to the result of the comparison. |