Application Of Fourier Optical Signal Processing To Detect Surface Flaws In Transmissive And Reflective Materials

The use of two-dimensional Fourier optical signal processing has been applied to the field of surface defect detection. Both transmissive and reflective objects can be analyzed using this system. The object is placed in a coherent optical processing system. By selectively blocking information in the frequency spectrum which contribute to background light and noise levels, only information relating to physical defects in the test object will be observed at the output plane of the system. The system has been observed to be relatively impervious to mechanical vibration, allows for the inspection of large areas instantaneously, and has relatively good resolution.