In order to eliminate impulse noise and preserve the fine structure features of the image

a method of the image denoising based on monotony set operator is presented. This method

firstly

uses the threshold decomposition principle to decompose the image into a bank of level sets

and then apply a special set operator to filter the level sets

finally restructure a image with the level sets filtered. To compare with traditional medial filter and Gaussian filter

the image denoising method based on set operator has the characteristics of shape preserving and contrast invariant. In addition

Fast algorithm based on Heap data structure is presented in order to increase the efficient of the filter algorithm. According to connection

the algorithm can find maximum and minimum regions

and if the area of the regions is less than a special value

then they will be cut. So the small peaks and small vales in the image can be eliminated. Experimental results show that the efficient of the algorithm is obvious over the method used one by one threshold

and set operator has remarkable advantages in terms of eliminating impulse noise

shape preserving and contrast invariant.