A new image correction method based on projection sinograms is proposed to remove ring artifacts in industrial Computerized Tomography (CT) and to improve the precisions of post processing and quantitative analysis. An S-L filter is adopted to filter original projection data and to enhance artifact information. Then

the filtered projection data are processed by line integral and difference to further increase the difference between artifact edges and work piece contours. Furthermore

the differenced projection data are averaged according to the number of interpolations

and the artifact location is automatically searched according to the threshold selected by normal distribution. Finally

the projection data of ring artifacts are corrected by combining the linear interpolation and linear extrapolation. A correction experiment is carried out in the actual CT images including ring artifacts. The result indicates that the SNR of gray image using the proposed method has increased by 1.688 dB

which shows that proposed method effectively eliminates the ring artifacts and keeps the image edges and resolution as compared with the methods of polar coordinate transformation or Wave-FFT. The proposed method is suitable for correcting the discontinuous ring artifacts caused by detector faults and unstable performance.