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Nonlinear filter plays an important role in the field of image processing due to their ability to perform noise cancellation effectively. The median filter is one of the best known nonlinear filters. In median filtering, a pixel is replaced with the median within a window even if the pixel is not corrupted. Some filters based on a detection-estimation strategy are proposed to solve this problem. Even though the performance of the detection-estimation style filters are better than the conventional filters, the filtering result of these detection-estimation style filters still can be affected by the corrupted elements in the input vector. In this paper, a novel nonlinear filter is proposed to solve this problem. The new filter, called the error- trimmed median filter, trims the corrupted elements in an input vector before feeding it into the median filter. In this way the filtering capability of the filter is increased significantly. To detect the corrupted elements in the input vector the technique of the adaptive fuzzy linear regression is used. The adaptive fuzzy linear regression is a new method proposed in this paper to approximate the optimal solution of the fuzzy linear regression. The computer simulations based on the MSE and MAE error criterion show that the filtering capability of the error-trimmed median filter is good even when the noise ratio is high.
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