Bilateral filter. Filtering can be used in various engineering and scientific problems such as signal processing, image processing/analysis, electronic, physics electronic, chemistry and etc. In image processing and analysis, filters are used for de-blurring and smoothing. In addition, with the help of the filters some facts which are clear in the original image will be blurred and the final image will be enhanced. With considering the best sigma value for bilateral filter, after comparing all these four filters we will find out that the bilateral filter is the best.