A New Improved Filtering Algorithm Based On Median Filter Algorithm

Whth the development of computer technology, the technologies of image processing gained great interests and wide applications, many new theories and new processing methods were proposed in recent years. Because of communication channel and so on, the signal pixels are always with noise pixels together. Image filter algorithm is always study focus in the field of image processing and analysis, which is still unresolved well till now.Salt and pepper noise is a kind of common noises which can be eliminated by image filtering algorithms. The standard median filter is one of the most popular nonlinear fiters. Because standard median filter is simple and effective, it was widely used in many domains, but it had a very clear deficiency. The filter effects are influenced by the length of template window. Small template will lead to bad effects and big template will lead to image blurring. On the other hand, all the pixels are replaced with the median value of their neighborhood. Although the noise pixels are replaced, the signal pixels are also replaced that lead to the uncorrect spread of noise.This paper presents a new improved median-based filtering algorithm to improve standard median filter algorithm. This algorithm gives a new decision criterion. Firstly, this decision citerion calculates the correlation value with its neighbors. And then the value is worked as the measure that we determine whether this pixel is a noise pixel. The simulation experiment shows that this algorithm can protect image signal detail as much as possible when effectively eliminates salt and pepper noise.Firstly, this paper introduces the basic knowledge of digital image. And then introduces the principle of the standard median filter method, analyzes its deficiency and compares the standard median filter with many other new improved median filters. This paper presents an innovative improved median algorithm, makes a detailed exposition of the implementation method and gives simulation experiment data. At last, the simulation experiment shows that ISM filter can detect noise pixel effectively, get higher SNR and lower omission rate and lower false drop rate. So the ISM algorithm has better filtering performance than standard median filter.