A Study on Development of Optimal Noise Filter Algorithm for Laser Vision System in GMA Welding

Abstract

In recent years, noise filter of image processing have been widely used in automated manufacturing processes in noisy environment, such as removal of noise in arc welding process, because such filters are robust even in the presence of extreme noise. Since arc, soot and splash etc., salt noise which has certain noise amplitude at random location was found in captured image. It is important to employ a noise filter to intensify the laser lines and ultimately remove or reduce the noise. In this study, the welding seam image captured from the CCD camera was processed by noise filters to remove the noise due to the complexity of welding environment. Comparison of three noise filters (Gaussian filter, Median filter and Wiener filter) was made to find out the optimal noise filtering algorithm. The result showed that the Median filter algorithm is the preferred method, as not only this algorithm performance provided lower MSE (Mean Square Error) and RMSE (Root Mean Square Error) values than those of Gaussian filter and Wiener filter, but also the values of the PSNR (Peak Signal-to-Noise Ratio) and SNR (Signal-to-Noise Ratio) were higher. Therefore, the Median filter can be considered to have a better enhancement effect than the other two filters.