Surface inspection for quality control is the most important part of today's highly competitive industrial production. There are a great number of manufacturing processes where inspection for surface finishing or surface defects is attempted: steel strip

hot steel slabs

plastic plates

painted surfaces

wooden surfaces

profiles and etc. But the surface inspection is usually a bottleneck in many production processes. Reliable and effective detection of machined surface defects is of great importance in automatic industry that needs high surface aesthetics and machined precision

it can obviously enhance the entire efficiency for the automatic manufacturing. A novel image filter has been developed in this paper

it transforms the original image via FFT and then filters out those Fourier areas which Fourier energy concentrates on. These Fourier areas correspond to the background texture on machined directions. The method can enhance the texture defects and reduce the effect of background texture by analyzing the texture features of machined surfaces. Then the texture defects can be easily detected through the segmentation of defects and background. The experimental results have shown that the method can obtain precise results and high detection speed.